hot ice cream experiment

How to Make Hot Ice Cream

by Science Explorers | Oct 15, 2019 | Blog | 0 comments

There’s no doubt about it — children of all ages love ice cream. While you can make a strong case that ice cream is a wonderful treat year-round, you can make an equally compelling argument that ice cream is even more enjoyable when it’s warm outside.

Even neat “freaks” will likely admit sticky hands are a small price to pay for the pure joy that often accompanies eating an ice cream cone and we heartily agree. While there’s no denying how enjoyable ice cream is, there’s also no way to ignore the learning opportunities that go hand-in-hand with making a new version of the familiar treat — hot ice cream.

Did You Say “Hot Ice Cream?”

We know, we know — you’re probably thinking we’re trying to trick you, but we’re not. Hot ice cream is a real thing that’s just as mouth-watering as regular ice cream. Once you know how to make hot ice cream, you’ll realize making it is a great way to teach children about math and science while having a ton of fun in the kitchen.

Unlike traditional ice cream, hot ice cream is made with methylcellulose, which is a thickener that works at high cooking temperatures. Hot ice cream is poached, which also differs from the way conventional ice cream gets made. Whereas regular ice cream melts as it gets warm, hot ice cream melts when it cools down.

The Math and Measurements Behind Hot Ice Cream

As you know, you can measure ingredients in various ways. Two typical units of measure are grams and ounces. One gram is the equivalent of 0.03527396195 U.S. ounces. In our hot ice cream recipe, we’ll present measurements in both grams and U.S. ounces although we’ll round the gram to ounce ratio to 1:0.0353. You can have them do the math to convert the measurements on their own to give the kids you’re cooking with a chance to practice or improve their math skills

The Ingredients for Hot Ice Cream

You can make hot ice cream in just about any flavor imaginable. While you may want to experience with different varieties as you perfect the art of making hot ice cream, it’s wise to start with a basic flavor such as vanilla. Here are the ingredients you’ll need to prepare a tasty batch of hot vanilla ice cream:

• 306 grams or 10.8 ounces flavorless yogurt
• 230 grams or 8 oz softened cream cheese
• 80 g or 2.8 ounces honey or, preferably, agave nectar
• 154 grams or 5.4 oz water
• One teaspoon (or more, depending on your preferences) vanilla extract
• A tiny pinch of salt (optional for kids on a low sodium diet)
• 11.55 grams or 0.4 ounces methylcellulose

Steps to Make Hot Ice Cream

Once you gather your ingredients, here’s what you’ll do next:

• Combine the yogurt, cream cheese, honey or agave nectar and vanilla extract in a bowl. Mix the ingredients using a spoon, whisk or handheld immersion blender to make a base for your ice cream.
• Bring the water to a boil and then reduce the heat to medium.
• Add the methylcellulose to the hot water and whisk non-stop until the mixture is uniform.
• Remove the hot mixture from the stove, carefully pour it into your ice cream base and whisk to combine everything.
• Pour your combined based into a cup and cover it tightly using plastic wrap.
• Put the filled cup in an ice bath for a minimum of one hour. If you’re going to chill your ice cream base overnight, put the ice bath and the cup of base it contains in the refrigerator.
• When your base is sufficiently chilled, bring a pot of water to a boil and then reduce the heat to simmer.
• Carefully lower a spoon or scoop full of your base into the water, wait 3-5 seconds and turn your kitchen tool to the side to release the base into the warm water.
• Allow the ice cream to cook in the water for a minute or two or until it feels a bit spongy like prepared Jell-O.
• Use a slotted spoon to remove your cooked ice cream balls from the water and put the balls on a paper towel for a few seconds, just long enough for them to shed any excess water.
• Transfer the ice cream balls to a plate or bowl.
• Top your ice cream with a sauce or sprinkles if desired.
• Grab a spoon and enjoy your freshly prepared hot ice cream.

Give Kids the Chance to Learn More Cool Stuff With Science Explorers

While you’re now well-prepared to teach your children or students how to make hot ice cream, you can give them the chance to learn even more through the   summer science camps   and   after-school science clubs   hosted by Science Explorers. Give us a call or contact us online to learn more today.

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Why Does Ice Cream Melt On A Hot Day? The Answer: Heat Conduction.

By -->jeremy watt -->, posted june 2, 2010.

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Live a single day on planet Earth, or anywhere else in the universe for that matter, and you will experience the natural phenomenon of heat conduction, which is the term used to describe the natural flow of heat from warmer objects to cooler ones.

Your favorite scoop of ice cream melting on a hot summer day is a perfect example of heat conduction where heat from the air is naturally drawn to the much colder ice cream scoop.

Heat Conduction

Because it is so commonly experienced in our daily lives, humankind has certainly had some understanding of heat conduction for a very long time.

But not until the 19th century was this understanding sharpened by a French politician and scientist named Joseph Fourier who made a single equation, now known as " Fourier's law " or the "Law of Heat Conduction," that models heat conduction so well it has been little altered since its creation.

To get a handle on the value of this model equation let's go back to the ice cream scoop.

The end result is obvious to our intuition, that the ice cream will eventually melt completely, because we know heat naturally flows from warm to cold. But what is not so obvious is the exact amount of time it will take that ice cream to melt all the way.

Time Needed

Taking some additional information into account like the size of the scoop, as well as the kind of bowl or ice cream cone it's held in, Fourier's law gives us a good estimation for the time it takes the ice cream to melt.

This makes it very useful not just for ice cream lovers, but for anyone interested in keeping something cool in a hot environment or vice versa. Such as computer chip manufacturers or airplane insulation designers.

About A Moment of Science

A Moment of Science is a daily audio podcast, public radio program and video series providing the scientific story behind some of life's most perplexing mysteries. Learn More »

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Supercool theory solves hot ice cream puzzle

By Marcus Chown

2 December 1995

HOW is it possible for hot water to freeze more quickly than cold? This peculiar phenomenon, first noticed by Aristotle in the 4th century BC, has baffled scientists for generations. But a South African physicist now claims that the answer lies in water’s ability to remain liquid below its normal freezing point. “It’s all to do with supercooling,” says David Auerbach, who works at the Max Planck Institute for Fluid Dynamics in Göttingen, Germany.

The phenomenon is today known as the Mpemba effect, after the Tanzanian schoolboy Erasto Mpemba. In the 1960s, Mpemba became a laughing stock after telling his science teacher he could make ice-cream mixture freeze faster by warming it before putting it into the freezer.

Since then, many explanations have been proposed (see The Last Word, this issue). Mpemba himself ruled out two of the most obvious. One suggestion was that the hot mixture melted a layer of loosely packed frost under its container, which then refroze as a solid layer of ice which conducted heat away more rapidly. The other was that strong evaporation both cooled the hot mixture and left less water to freeze. But Mpemba found the hot mixture froze first even when it was placed on a block of wood and covered with a lid.

Auerbach turned his attention to the Mpemba effect last year while on sabbatical at the Institute for Water Research in Perth, Australia. He plunged two sealed 100-millilitre beakers – one containing water at 18 °C and the other at 90 °C – into a bath of cold ethanol and monitored their temperature with a thermistor pasted to the wall of each.

Over the course of 103 experiments, Auerbach found that the Mpemba effect was not a hard-and-fast rule. Sometimes the hot water appeared to freeze first, sometimes the cold. Invariably, however, Auerbach found that the water in each beaker did not start to freeze until its temperature was well below 0 °C. When freezing began, branching “ferns” of ice shot out from the walls of the beaker into the water as the temperature jumped back to 0 °C. “You can see the same effect when frost forms on the inside of a bedroom window,” says Auerbach. “It’s an unmistakable signature of freezing after supercooling.”

The ice crystals grew to fill the beaker in less than a second, leaving a mush of ice and water (American Journal of Physics, vol 63, p 882). “This is also typical of supercooling,” says Auerbach. “If the water is close to zero when it freezes, the mush is mostly water; if it is much below zero, it is mostly ice.”

Auerbach says that the temperature at which a supercooled liquid starts to freeze is inherently unpredictable. When the Mpemba effect occurs, says Auerbach, it is because the sudden appearance of ice crystals from the supercooled liquid occurs at a higher temperature in the water that was formerly hot. Nevertheless, he says, the apparently solid mass of ice that results is still largely composed of water. Even if the hot water starts to freeze first, the cold water is always the first to freeze completely.

Auerbach found that the Mpemba effect seemed more frequent if the ethanol bath was held between −5 °C and −10 °C. He has no explanation for this apparent bias, and adds that more experiments are needed to confirm that it was not a statistical fluke. If the bias is real, however, it could explain why Mpemba’s hot ice-cream mixture usually appeared to freeze first.

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Hot Ice For Summer

Creating Hot Ice: A Great STEM Experiment For Summer

There’s a Dad joke waiting in this project.  Make sure to grab it while you can!

“Son, it’s been so hot this summer that even the ICE is hot!”  

You can buy ice in the supermarket but hot ice you’ll have to make yourself.  Making hot ice is an easy fun experiment three to eight-year-old  kids can try with ingredients you have at home.  It takes about  1-2 hours  to conduct the experiment.    Your children will be amazed as the “ice” forms yet isn’t cold at all!

Hot ice is used in hand   warmers, heating pads, for a buffer in laboratory settings, and for pickling and tanning of food.  It’s chemical name is sodium acetate.

You also may be interested in:

• Kiwi Co Reviews
• Fireproof Balloon Science Experiment
• Dancing Raisins

Supplies Needed

• A heat safe measuring jar or glass cup  
• 4 Cups of white vinegar which is  acetic acid
• 4 Tablespoons of baking soda which is  sodium  bicarbonate
• Hot plate  
• A spoon or spatula
• A pot or saucepan  (do not use a copper pot)

What Mystery Are We Solving?

Make hot ice and when you put your hand in the liquid the hot ice is formed around your fingers. It looks like your fingers are frozen, but it is hot to the touch.   

How does to everyday ingredients create ice that is hot to the  touch ? Isn’t ice supposed to be cold?

Safety Issues

Although young kids can create their own hot ice, adult supervision is recommended when the liquid is boiled.   

Hot ice isn’t the same as dry ice! Dry ice may cause severe burns when touched but hot ice is mostly harmless. For some people, hot ice may  irritate skin and eyes in the same manner vinegar would.  

How To Make Hot Ice

• Pour 4 cups of white vinegar into the saucepan or pot.
• Slowly add 4 tablespoons of baking soda a little at a time to the vinegar.  The liquid fizzes when the baking soda is added.  Stir with the spoon to mix the two ingredients as you add the baking soda.
• Wait for the fizzing to stop before you continue. 
• Place the pot on the hot plate  and boil at medium heat  until the fluid  evaporates  and you’re left with a dry sol vent .  It should take about 30 -60 minutes for all the liquid to disappear. 
• When the liquid starts forming a crusty film on the surface, turn the heat down immediately to prevent it forming a thick crust.  (Scrape some of the crystals off the side of the pot to use later)
• If the solution is brown and cloudy, add more vinegar. Boil again.  
• Break up the lumps in the powder solution.
• Place the powder in the glass container  with a lid  and add water until it dissolves into a liquid.  (66 g of water for every 100 g of powder) Cover with the lid to prevent more evaporation. 
• Place the glass jar in a container with ice water to cool down. It takes about 15 minutes. You may also cool it in the fridge , but it will take longer than the ice water. 
• When you put your hand in the glass jar, the hot ice forms crystals around your hand and it is frozen to the touch.   

What Just Happened Here?

The chemical reaction is also exothermically creating the hot feeling when touching the ice.   

The physical change is noticeable when the liquid mixture releases gas and changes into a solid form.  When water is added the powder dissolves.   

The solution  is a supercooled liquid that  stays liquid when cooled down below its freezing point in the ice water.    

The  unstable supersaturated  liquid will freeze forming crystals at the slightest trigger  when adding some of the crystals to the solution. For a cool effect dip your fingers  into  the liquid .   Crystallization  forms at the nucleation site whe n  solute molecules that bump into each other overcome the power of the sol vent that keeps molecules apart .   

More Resources

https://www.wikihow.com/Make-Hot-Ice  

https://www.youtube.com/watch?v=XiAv9GE_2o4  

https://www.playdoughtoplato.com/kids-science-experiment-hot-ice/  

https://www.thoughtco.com/hot-ice-or-sodium-acetate-607822  

Retha Groenewald is a professional writer working for FractusLearning. When not working with Fractus, she is web copywriter for the Christian market. Her writing is featured at Christian Web Copywriter and at Writing That Breathes Life.

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Summer Science for Hot Days

June 12, 2023 By Emma Vanstone 11 Comments

The UK is hot, hot, hot at the moment, so today, I’m sharing some fun and cooling summer science experiments that are great for kids of all ages on a sunny day!

Sometimes science experiments outside feel so much easier than making a mess inside, and they are a great way to keep kids entertained through the school holidays.

Make your own slushy drinks with ice and salt, track the movement of the sun with a DIY sundial , make a solar oven, and LOTS more easy summer science and STEM challenges!

Summer science for hot days

Science experiments with ice, summer 5-minute slushy drink.

One of our favourite summer activities is exploring the melting and mixing of colours by making slushy drinks with fruity ice.

You’ll need salt, ice, two sealable plastic food bags and various different fruit juices to make a colourful slushy drink in minutes!

Paint on ice

Can you make some summer-themed ice? Try adding flower petals or shells to your creations.

Painting on a sheet of ice is great fun too. The paint slips beautifully over the ice, making it a lovely sensory activity.

Melting ice cubes

How about making some ice cubes and investigating where they melt the fastest . Try them inside, in the fridge, outdoors in the sunshine and outdoors in the shade.

Or, try creating an ice excavation. You could go all out and make a huge one or lots of mini ones icy rescues.

Make ice cream in a bag

Find out why salt melts ice , and use your new knowledge to make ice cream in a bag or cool a drink down quickly.

Science in the paddling pool

If you have a paddling pool, I have 5 paddling pool science activities that make playing in the pool even more fun than usual!

Lolly stick races

Challenge your friends to a  lolly stick race . These are great fun and an unusual water table or paddling pool activity.

Once you’ve finished racing, use the soapy water to clean outdoor toys!

Sink or float experiments

Finally, testing objects to see whether they sink or float is always fun! Older children can try wrapping objects that sink in bubble wrap to find out if reducing their density helps them float or make mini boats for sinking objects.

Science in the kitchen

Do you love ice cream? How about making some ice cream soup like Rainy Day Mum.

Or make s’mores in an easy garden solar oven ?

Cool a drink quickly using the cooling power of ice and salt. This uses the same science concept as ice cream in a bag.

Adding salt to a mixture of ice and water lowers the freezing point of the ice. The melting ice draws heat from the drink, cooling it down!

Outdoor summer science activities

Diy sundial.

Track the movement of the sun with a sundial made with a stick .

Water Wall Ideas

Little ones love a water wall, we’ve got some easy homemade water wall ideas for you to try. Water walls are a great design challenge for older children and fun to play with for little ones.

Shadow frames

Shadow frames are brilliant fun. Another idea is to make an empty frame and draw a picture in the middle to cast a shadow!

You can also try drawing the shadow a toy creates. Does the shape of the shadow change throughout the day?

More summer science for kids

Our 50 fun summer science activities will keep you busy all summer long!

If you prefer a challenge, our summer science challenges could be just what you’re looking for! NOW with FREE printable challenges!

Last Updated on June 13, 2023 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

July 10, 2013 at 2:16 pm

I have to try and freeze water balloons too. I just posted about our water and ice experiment (weighing ice and water) at http://learningwithmouse.blogspot.com/2013/07/ice-and-watervolume-and-weight.html

July 15, 2013 at 1:31 pm

Some brilliant ideas, thanks for linking up to our Parenting Pin It Party.

July 19, 2013 at 8:25 pm

Thanks for hosting Cat x

July 15, 2013 at 5:23 pm

Great ideas i love them all particltaly the balloon ice

July 19, 2013 at 8:17 pm

Aww thanks Becky 🙂

July 16, 2013 at 1:01 pm

I can’t think of anything better for a hot day!

Thanks Helen. x

July 16, 2013 at 8:30 pm

These are great ideas for hot days. Pinning these on my August pinboard. Thanks!

Thank you. x

July 21, 2013 at 5:29 pm

Hi – great post, we’re going to feature this on the parenting pin i party tomorrow- hope that’s OK

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Make Hot Ice From Baking Soda and Vinegar

Hot ice is another name for sodium acetate (CH 3 COONa or NaOAc). It is the sodium salt of acetic acid, which is the key component of vinegar. Hot ice gets its name from the way it solidifies. A solution of sodium acetate supercooled below its melting point suddenly crystallizes. Heat is released and the crystal resemble ice so… “hot ice.” All you need to make sodium acetate and crystallize it into hot ice is baking soda and vinegar. It’s a great chemistry demonstration because it illustrates chemical reactions, supercooling, crystallization, and exothermic processes . From start to finish, the project takes less than an hour. Once you have the sodium acetate, you can melt and crystallize it over and over again.

You only need two ingredients, plus a pan and stove:

• 1 liter Vinegar (weak acetic acid)
• 4 tablespoons Baking soda (sodium bicarbonate)

The quantities of baking soda and vinegar are not critical so long as all of the baking soda dissolves. If measuring the ingredients isn’t an option, just dissolve baking soda in vinegar until no more dissolves, filter off the liquid using a coffee filter or paper towel to remove any solids, and proceed from there.

Be sure to use plain white (clear) vinegar and not cider, red wine, or some other colored vinegar. You can substitute sodium carbonate (washing soda) or sodium hydroxide (caustic soda or lye) for the baking soda. If you have access to pure sodium acetate (inexpensive online), you can skip the procedure to make it and go directly to the step for re-using it.

• The first step is reacting the baking soda and vinegar . Stir baking soda into vinegar a little at a time. If you add it all at once, you’ll basically get the classic baking soda and vinegar volcano and could overflow your pan! The reaction between baking soda and vinegar produces sodium acetate, water, and carbon dioxide gas: Na + [HCO 3 ] –  + CH 3 –COOH → CH 3 –COO –  Na +  + H 2 O + CO 2 However, at this point there’s too much water for the sodium acetate to crystallize.
• Next, concentrate the solution by boiling it. It took me about an hour at medium heat to reduce the volume from a liter to about 100-150 milliliters. Don’t use high heat because you may get discoloration (golden or brown). The discoloration doesn’t ruin the sodium acetate, but the hot ice will look a bit like you made it from yellow snow. You’ll know you’ve boiled off enough water when a crystalline skin starts to form on the surface of the liquid.
• Once you see a skin, immediately remove the pan from the heat. Carefully pour the liquid into a clean container and cover the new container with plastic wrap or a lid to prevent further evaporation. You should get crystals in the pan, which you can use as seed crystals for activities, but the liquid in the new container should not contain any crystals. If you do have crystals, stir in a very small volume of water or vinegar to dissolve the crystals. If the entire solution crystallizes, add more water and go back to the stove to boil it down again.
• Place the covered container of sodium acetate solution in the refrigerator to chill it. It’s also fine to let the solution cool to room temperature on its own, but this takes longer. Either way, reducing the temperature produces a supercooled liquid. That is, the sodium acetate remains liquid below its freezing point.

Hot Ice Activities

Solidification of sodium acetate is the basis for one type of hot pack , but it’s also great for crystallization demonstrations. Three popular activities are the “sea urchin,” “flower,” and “tower.”

• Sea Urchin : Pour the cooled liquid into a clear container. Use a toothpick or bamboo skewer to scrape a few sodium acetate crystals from the pan used to make the solution. Dip the toothpick into the liquid so the tip with crystals are in the middle of the container. Needle-like crystals immediately grow out from the center. Also, crystallization releases heat as chemical bonds form to make the solid. The final structure resembles a spiny sea urchin.
• Flower : Pour the cooled sodium acetate liquid into a flat dish (preferably a dark-colored one). Scrape one or more crystals from the pan and drop them onto the liquid. The crystals act as seeds . The hot ice crystals spread out radially and form structures that resemble flowers.
• Tower : Place a few crystals onto a surface. Slowly pour the liquid onto the crystals. The hot ice solidifies as you pour the liquid, forming a tower (or whatever shape you can manage).

Re-Using Hot Ice

Save the solid sodium acetate so you can use it again without going through the whole baking soda-and-vinegar process. Simply dissolve the hot ice in water and boil off the smaller amount of excess water.

Safety Information

Sodium acetate is a safe, non-toxic chemical, so it’s perfect for chemistry demonstrations. It is used as a food additive to enhance flavor and is a key ingredient in some chemical hot packs. The heat released by hot ice crystallization of a refrigerated solution doesn’t present a burn hazard. However, making hot ice from baking soda and vinegar does involve boiling liquid on a stove, so adult supervision is required. If you use sodium hydroxide in place of baking soda, heed the cautions on the product label.

• ChemEd Xchange (2019). “ Crystallization of Supersaturated Sodium Acetate – Demonstration .”
• Clayden, Jonathan; Greeves, Nick; Warren, Stuart; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. ISBN 978-0-19-850346-0.
• Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds . Van Nostrand.

Related Posts

STEM Challenge of the Month: Shake It Up Ice Cream!

Published by stem like a girl on november 26, 2018 november 26, 2018.

Stop what you are doing, grab your daughter, and try this STEM challenge RIGHT NOW!  What better way to learn about physics and chemistry than with a tasty home made ice cream challenge?  We had so much fun testing (and tasting!) this out and know you will love it too!

Ever wonder why people put salt on icy roads in the winter?  Salt lowers the freezing point of water.  Water melts at 32 degrees Fahrenheit so if the road temperature is below that, ice will form.  But when you add salt to water, the freezing point can drop down to 0 degrees Fahrenheit meaning that it takes a lower temperature to keep the ice frozen.  This means that even if the road temperature is below 32 degrees but you add salt, the ice will start to melt.

Having a hard time visualizing this?  Take two ice cubes and sprinkle salt on one of them.  Watch what happens and you’ll see how the addition of salt makes the ice melt faster.  Both ice cubes will eventually melt at room temperature but the salty ice cube melts faster due to the lower freezing/melting point.

So how can we use this to make ice cream?  In order to make cream freeze, the temperature would need to be below 32 degrees Fahrenheit.  By adding salt to ice and conducting this experiment at room temperature (~67 degrees), the salt will begin to melt the ice making a solution that is less than 32 degrees allowing the cream to freeze faster.

Now sure, you could put cream into the freezer at 32 degrees and it will eventually freeze but that would take much longer and result in a pretty hard and icy bowl of ice cream.  To get that creamy texture we all love about ice cream, we need to introduce air into the cream.  This can be done by stirring or shaking.  Moving the cream particles around while being exposed to the cold temperature gives it that creamy texture while also allowing for better heat transfer between the salty ice and the cream.

So let’s give it a try!  Grab the ingredients and get ready to shake it up for an edible ice cream treat!

• 1/2 cup heavy cream or half and half
• 1/4 tsp vanilla extract
• 1 TBS sugar
• 1/3 cup kosher salt or table salt
• Large ziplock bags
• Small ziplock bags
• Shake It Up Ice Cream Experiment Test Sheet

• Download and print the Shake It Up Ice Cream Experiment Test Sheet .
• Combine the heavy cream or half and half, vanilla extract, and sugar.  Pour this mixture into one of your small ziplock bags.  Make one bag for each variable you are testing.  We tested ice alone, ice + table salt, and ice + kosher salt.
• Fill the large ziplock bags about 1/2 fill with ice cubes.
• Dump salt into the bags and then place your small cream-filled bag inside it.  Make sure both bags are sealed up well.
• Start shaking!  We suggest putting on some music and having a dance party while you shake.  Make some observations about what is happening inside your bags.  How do they look and feel with or without salt?  What is happening to the cream inside the small bag?
• After about 5 minutes of shaking, open your bags and scoop the contents of the small bag into a bowl.  Do you notice any difference between the bags that contained salt and the one with just ice?
• Add sprinkles, chocolate syrup, or your favorite topping and enjoy your home-made science experiment!

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Ice Cream Lab

Introduction: Ice Cream Lab

What a fun way to learn! Make up some ice cream to discuss solutions, mixtures, saturation points, melting point, freezing point and physical changes.

The ice cream lab can be used at several grade levels. I use it in the fourth grade to discuss physical changes. I also used this activity in 5th, 6th, and 8th grade over my 25 years teaching. For older grade levels we discuss solutions, mixtures, saturations, ... along with the physical changes that are taking place in this tasty activity.

Step 1: Materials

Heavy Cream

Tablespoons x3

Permanent Marker

Dropper or Pipette

Pint Size Freezer Bags

Quart Size Freezer Bags

Light Cream (Half and Half)

Print directions and Signs.

Attachments

Step 2: Post Directions

I have been doing the ice cream lab for over 20 years and found that posting the directions is best. I no longer have students asking me 20 times what is next (even when they had a paper with directions in their hand). I now just point to the wall. Use the directions provided with this instructable or make your own.

Print Directions

Laminate - It is a good idea to laminate directions so they can be reused year after year and the lamination prevents the signs from getting wet.

Post to wall

Step 3: Assebly Line

I have an assembly line procedure where kids work with partners.

I have an assignment for students to work on during class. As students work at their desks I pick two students that are working well. This keeps down on the chaos as more and more kids come up to make their ice-cream. Once students are done making and eating, they can go back to their seat work.

Step 4: Add Ingredients

The first sign has the recipe of 6 Tbsp of Heavy Cream, 6 Tbsp Half and Half, 2 Tbsp of sugar, 2 drops of vanilla.

Have all ingredients and supplies out and ready. Put the ingredients and supplies in the order the students will need them.

Pick two students to come back to the ingredients.

Right at the beginning of the assembly line students are provided with one pint size freezer bag. The kids pick it up and move to the next "station".

In the following stations students "add all ingredients to the small bag" (sign two). Refer students to the first sign for the ingredients.

Seal bag completely (sign three). I have found that getting out as much air as possible helps with the mixture freezing more effectively and cuts back on bags popping open.

Step 5: Ice Time

Put the smaller bag (pint size freezer back) into a quart size freezer bag (sign four).

Fill large bag with ice (sign five).

Step 6: Add Salt

Add 2 Tbsp of ice cream salt (sign six). Seal bag.

Using the permanent marker put name on bag and set to the side.

Go back through the assembly line with partner to make their bag up.

Step 7: Shake

Once both partners have gone through the assembly line, shake the bag continuously for 10 min (seventh sign).

Have the kids watch the clock and stop after 10 minutes. No need for them to go longer. I have found that several kids have had great frozen ice cream but continued to shake past the 10 minutes and end up with a milk shake instead.

Step 8: Enjoy!

The ice cream was well set up and clearly went through a physical change. Freezing and melting are wonderful examples of a physical change and phase change.

Step 9: Ohio's Learning Standards

The standard that I want to focus on is - 4.PS.1: When objects break into smaller pieces, dissolve, or change state, the total amount of matter is conserved.

PHYSICAL SCIENCE (PS) Topic: Electricity, Heat and Matter

This topic focuses on the conservation of matter and the processes of energy transfer and transformation, especially as they apply to heat and electrical energy.

CONTENT STATEMENT4.PS.1 When objects break into smaller pieces, dissolve, or change state, the total amount of matter is conserved. When an object is broken into smaller pieces, when a solid is dissolved in a liquid or when matter changes state (solid, liquid, gas), the total amount of matter remains constant. Note:Differentiation between mass and weight is not necessary at this grade level.

CONTENT ELABORATION

Prior Concepts Related to Changes of Matter

PreK-2: Simple measuring instruments are used to observe and compare properties of objects. Changes in objects are investigated.

Grade 3: Objects are composed of matter, which has mass and takes up space. Matter includes solids, liquids and gases (air). Phase changes are explored. Heating and cooling is one way to change the state of matter.

Grade 4 Concepts: Some properties of objects may stay the same even when other properties change. For example, water can change from a liquid to a solid, but the mass of the water remains the same. Parts of an object or material may be assembled in different configurations but the mass remains the same. The sum of the mass of all parts in an object equals the mass of the object. When a solid is dissolved in a liquid, the mass of the mixture is equal to the sum of the masses of the liquid and solid. At this grade level, the discussion of conservation of matter should be limited to a macroscopic, observable level. Conservation of matter should be developed from experimental evidence collected in the classroom. After the concept has been well established with experimental data and evidence using closed systems (i.e., systems where matter cannot enter or leave the system), investigations can include interactions that are more complex where the mass may not appear to stay constant (e.g., fizzing tablets in water). Mass is an additive property of objects and volume is usually an additive property for the same material at the same conditions. However, volume is not always an additive property, especially if different substances are involved. For example, mixing alcohol with water results in a volume that is significantly less than the sum of the volumes.

Future Application of Concepts

Grades 6-8: Conservation of matter in phase changes and chemical reactions is explained by the number and type of atoms remaining constant. The idea of conservation of energy is introduced.

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Use Engineering To Design The Perfect Ice Cream

Grade level, general science, stem practices, analyzing and interpreting data , constructing explanations and designing solutions , planning and carrying out investigations, activity type:, experimental design , engineering , physical science , food science.

How quickly will an ice cream sandwich melt? Well, that depends on a lot of factors, including the weather. A few years ago, Walmart started selling an ice cream sandwich that did not melt, even when it was left outside in the sun for an hour on a 100-degree day. Someone even put one of the Walmart ice cream sandwiches on a grill and it didn’t melt for 10 minutes !

Why didn’t the Walmart ice cream melt? Pretty strange, right? Why does it seem like different ice creams melt differently?

Some may think a melt-resistant ice cream is a scientific achievement, especially if they prefer a firmer, longer-lasting ice cream. Others may prefer a softer, meltier ice cream experience. What do you like in a frozen treat?

In this activity, you’ll design your perfect ice cream. To do this, you’ll take on the role of a  food scientist and engineer, using experimental design to test the melting rate of different batches of ice cream, each with slightly different mixtures. Then, you’ll perfect your ice cream recipe to engineer your ideal ice cream experience. We’ll use the engineering and design process to guide our work.

This resource was created as part of the Science Friday Educator Collaborative .

The engineering design process.

You’ll use the engineering design process  to create a few batches of ice cream, each with different melting speeds. Then, you’ll perfect your recipe to achieve your ideal ice cream experience. Research, testing, and more testing are at the heart of food engineering.

Even in a food as seemingly simple as ice cream, there are several variables that can have a big effect on the final product: quantity and quality of ingredients, timing and temperatures, and more. How do we know what variables to adjust, how much to adjust, and what kind of impact those changes will have on our ice cream?

To understand all these variables, and to test them in a scientific way, food engineers apply the engineering design process. The first step in that process is research.

Activity 1: Research The Science Of Ice Cream

Ice cream is super cool (get it?)! Think about all the different ice creams you’ve eaten in your life. Flavors aside, how were they different? How were they the same? Can you recall some that melted faster than others?

These kinds of observations may be all you know about ice cream at the moment; with research, food engineers start to fill in the gap between observing that different ice creams melt at different rates, and being able to create an ice cream that melts in a specific way. Through research , you can familiarize yourself with background knowledge, ideas, problems and solutions that already exist. This saves you time in the future, and may even shape what and how you test.

For our activity, we’ll need to understand what ice cream is made of, how it’s made, and how its components can be changed to alter its properties. Let’s take a look at a couple of resources and answer some key questions about each, listed below and in the “ Research ” section of the Resource Handout .

Listen to the first six minutes of this Science Friday segment, Total Meltdown: The Rate of Ice Cream Collapse .

• What are the basic steps to make ice cream?
• What are the ingredients in ice cream?
• What are the parts of ice cream’s chemical structure?
• What are some things that affect melting rate? What is something free we can add to ice cream to change how fast it melts? How do scientists change how ice cream melts?
• What is overrun? What does having a big overrun cause?
• Do ice creams with more air cost more or less?
• Why is it important to use the same size of scoops when conducting your experiment?

Watch How Science Affects Your Ice Cream.

• What did you learn about the process of making ice cream from this video? What affects the rate of melt?
• What determines the consistency of the ice cream? How do ice crystals affect consistency?
• Ice cream is a mixture of what two things?
• What do the water and fats want to do naturally? How do you make sure the water and fat mix?
• What is another way of preventing your ice cream from melting faster?

Read the “Air is Important” and “Sugar and Fat” sections of this American Chemistry Society article, Ice, Cream …and Chemistry .

• What did you learn about the process of making ice cream from this reading? What affects the rate of melt?
• Questions for “Air is Important” – What ice cream ingredient do most people not see or know about? – What percentage of the volume of ice cream does air make up? – What is the amount of air added to an ice cream called? How does it affect the ice cream? – Ice cream is an emulsion. Explain what an emulsion is. – What two liquids are mixed together to make ice cream?
• Questions for “Sugars and Fats” – What is the purpose of sugar in ice cream? What is the purpose of fat in ice cream? – What is the problem with using fat as an ingredient? – Why don’t fat and water like to mix? How can you prevent the fat and water mixture from separating? – What is an emulsifier and how does it work? What is the emulsifier in basic ice cream?

Brainstorm Based On What You Have Learned

Discuss what you have learned with others. Compare the information from the three resources you used for your research. Did you notice any commonalities? What were the most important ingredients or techniques that affects the ice cream?

Putting together everything from your research, here are a couple of key facts you’ll want to keep in mind for the next activities:

• Ice cream is a special kind of substance because it is a combination of things that usually don’t stay mixed together—milk, fat, water, and air. This is called an emulsion .
• Emulsifiers, such as lecithin, allow the fat and ice to stay mixed together longer.
• The amount of air injected into ice cream plays a role in how fast it melts.
• Air and stabilizers are examples of variables that, as you adjust them, change the finished ice cream.

So, if you plan to make your own ice cream, how will you know which ingredients to adjust? Your research can get you part of the way to that answer, but what you’ll need to figure out how much to adjust the ingredients to get the results you want? You’ll do that by prototyping your ice cream and testing how it melts.

Total Meltdown: The Rate of Ice Cream Collapse

• 1 10 mL graduated cylinder Note: If you do not have access to a graduated cylinder, also gather these materials: – Tall glass – Teaspoon – Water – Dry erase or washable marker
• 1 funnel ( how to make a homemade funnel )
• Materials for at least 1 batch of ice cream Note: You will need additional materials for each test of a new recipe. – ½ cup of half-and-half – 1 tablespoon of sugar – ¼ teaspoon of vanilla – 1 sandwich plastic zipper bag – 1 gallon plastic zipper bag – 3 cups of ice – ⅓ cup rock salt – 1 roll of paper towels – Measuring cup – 1 lb coffee can (optional)
• Ice cream scoop
• Drinking straws
• Tapioca flour (optional)

Safety Note: Check for dairy allergies before beginning the experiment.

Activity 2: Prototype And Test A Basic Ice Cream Recipe

How do we determine what a fast melt and slow melt look like? What do we compare our ice cream to that will help us gauge whether the ice cream is melting quickly or slowly? For that, you will need to make a batch of “baseline” ice cream that is fairly average, like a tub of vanilla you’d pick up at the grocery store. This will serve as the baseline batch in your tests. Baseline data is data that is measured before anything has been adjusted, and it allows you to compare data before and after any changes you make.

With your baseline batch of ice cream, you’ll collect data on how fast it melts. Based on the differences you see between the baseline batch data and the data from your experimental batches, you’ll be able to see how your changes to the ice cream recipe affected the rate of melt.

Make Your Batch Of Baseline Ice Cream

To begin, copy down the recipe in the “ Baseline Recipe ” section of the Resource Handout from the slides below.

• Place ½ cup of half-and-half, 1 tablespoon of sugar, ¼ teaspoon of vanilla in the plastic zipper bag.
• Squeeze out as much air as possible and seal tightly. Make sure there are no leaks before moving onto the next step.
• Place 3 cups of ice and ⅓ cup of rock salt in the gallon plastic zipper bag.
• Place the sandwich bag inside the gallon bag and wrap the gallon bag in paper towels to protect from the cold.
• Shake the bag until ice cream is hardened. This will take roughly 15-20 minutes. Note: You may also place the bag in a 1 lb coffee can and roll the can on the floor.

You will need:

• ½ cup of half-and-half
• 1 tablespoon of sugar
• ¼ teaspoon of vanilla
• 1 sandwich plastic zipper bag
• 1 gallon plastic zipper bag
• 3 cups of ice
• ⅓ cup rock salt
• 1 roll of paper towels
• Measuring cup
• 1lb. Coffee can (optional)

Place ½ cup of half-and-half, 1 tablespoon of sugar, ¼ teaspoon of vanilla in the sandwich plastic zipper bag and close tightly.

Place 3 cups of ice and ⅓ cup of rock salt in the gallon plastic zipper bag.  

Place the sandwich bag inside the gallon bag and wrap gallon bag in paper towels to protect from the cold.

Shake the bag until ice cream is hardened. This will take roughly 15-20 minutes.

You may also place the bag in a 1 lb coffee can and role the ban on the floor.

Measure The Melt Rate Of Ice Cream

You will now collect data about how fast your baseline batch melts, which will give you a way to understand how fast or slow your experimental batches melt. Record your data in the “ Collecting Baseline Data ” section of the Resource Handout .

• Place a funnel on top of a 10 mL graduated cylinder.*
• Place one scoop of ice cream on the funnel (about ½ cup or 2 oz).
• Start the stopwatch.
• When the melted ice cream has filled the graduated cylinder to the 5 mL mark, stop the watch.
• In the “ Collecting Baseline Data ” section of the Resource Handout , record how long it took for 5 mL (1 teaspoon) of ice cream to melt.
• If you are working on your own, you may want to repeat this test a few times to make sure your results are consistent.

*If using the tall glass instead of the graduated cylinder, before you set up the funnel, measure 1 teaspoon of water and pour it into the glass. Take your marker and mark the side of the glass at the level of the water. Since 1 teaspoon of water is about equal to 5 mL, you have just marked 5mL on your glass. Next, dump out the water, dry the inside of the glass, and set up your funnel.

Reflection Questions

• In your opinion, did the ice cream melt slowly or quickly?
• What are some changes you can implement—AKA, variables—to make the ice cream melt faster or slower?
• Did you notice differences between this recipe and what you learned about ice cream in your research?

Activity 3: Improve The Ice Cream Recipe

Now the kitchen is yours! Do you like your ice cream to melt fast or slow? It’s time to create a recipe using as much or as little of any base ingredient. As you develop your recipe, carefully consider the results you want and adjust the recipe accordingly.

Think back to your research and the ice cream you just made.

• What went into the mixture?
• Which of those ingredients do you think will impact meltiness?
• Which do you think affects the melt the most?
• Based on your research, is there anything you can add to affect how fast ice cream melts.

Plan Your Variables For Your Ice Cream Recipe

Before you get brain freeze thinking about all the ingredients that could change an ice cream’s melting point, let’s take a minute to review the different kinds of variables we are working with to make sure we’re focusing on the right ones:

• The independent variable is the thing in the experiment you will change. That could be any of the ingredients in your ice cream recipe. It is best to only change one independent variable at a time to avoid confusing which variable is responsible for changes in your experiment
• The dependent variable is the item that will be measured and will change depending on the independent variable , in this case, how fast the ice cream melts.
• The control variables are all the other things that might change the dependent variable but that are not under investigation. These control variables need to stay the same for every trial or experiment , so that you can clearly tell how the independent variable is affecting the outcome. Your control variables could be the environmental temperature, the size of the ice cream sample, and all the rest of the ingredient amounts.

To keep things simple, let’s focus on two easy to change independent variables for an ice cream recipe: the amount of air and the presence of a stabilizer. These variables affect the size of the ice crystals in ice cream. The size of the ice crystals affects the creamy texture of the ice cream and how fast it melts. Changing one of these variables will change your ice cream overall.

Test Your Variables To Find The Meltiest Melter

Select one variable to change and decide how much you will adjust it. Write out your experimental ice cream recipe and the reasoning for your recipe changes in the Resource Handout . Hint : the reasoning behind your recipe changes should be based on the results of your research and your baseline trials.

Follow the procedure you used to make your baseline batch , changing only one variable at a time. For example, you might change the amount of air in the bag when you make your ice cream, but then you wouldn’t want to add stabilizer for that batch, because doing so would make it difficult to determine whether changes in your final ice cream were the result of the air, or the stabilizer. As you create your batches, you want to keep all the control variables the same (starting temperature, size of scoop, environmental temperature, etc).

Helpful Tip: To adjust the amount of air, insert the straw into the Ziplock sandwich bag. Close the bag around the straw. Suck out or blow in air to change how much air is in the bag. Then remove the straw and seal the bag.

Using the same procedure you used for your baseline batch of ice cream, test your new ice cream recipe. In the “ Data Collection for Experimental Trials ” section of the Resource Handout , record how long it takes for 5 mL (1 teaspoon) of ice cream to melt.

Share And Reflect On Your Findings

Look at the results from your baseline and experimental batches. Compare them with others, if possible. For this experiment, define “melts fast” as any batch that melts one minute faster than the baseline batch; define “melts slow” as any batch that melts one minute slower than the baseline batch.

• What were the amounts of air or stabilizer in the fastest melting batch?
• What were the amounts of air or stabilizer in the slowest melting batch?

Don’t forget to test the most important aspect of your ice cream! How did it taste?

Keep Iterating

Iteration is the repetition of a process in order to generate more outcomes. Keep iterating with new batches of ice cream, changing variables as you go. Now that you’ve had some practice as a food engineer, check out these other ways to learn more:

• Since you know the size of the ice cream scoop you used in each melting trial, you can plot out the relationship between the volume of ice cream and how long it takes to melt.
• What was the percent difference in melting rate between the baseline ice cream and your new designs?
• Think about how human errors might have affected your experimental design, and how to prevent them in future experiments.
• Consider more conditions and variables. For example, add more stabilizers, change the type of sweetener, or vary the amount of fat. Would skim milk work as well as half-and-half?
• Add fruit chunks, chocolate or strawberry syrup, or any other ingredient you can think of. Does it change the melt time? How?
• How could you test two independent variables at a time? Explore factorial experimental design to learn how scientists and engineers do so.

Food Failures: The Scoop On Perfecting Your Ice Cream And Frozen Desserts

The wide world of food engineering.

Food engineers are behind for all sorts of food we find on our grocery store shelves. So the next time you wonder why your cereal crackles in milk, or how that potato chip flavor came to be, imagine a food engineer at work, researching, testing and collecting data until they can create the perfect crunch, snap, melt, or tingle for your tongue. And the next time it’s your turn to cook a meal, think about how you could adjust a few independent variables to make the dish your own! You are already well on your way to becoming a food engineer yourself.

Next Generation Science Standards

This resource works toward the following performance expectations:

• MS-ETS1-3 : Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
• MS-ETS1-4 : Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
• HS-ETS1-2 : Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.

Credits: Written by Sergio Estrada Draft Development by Xochitl Garcia and Sandy Roberts Copyedits by Ariel Zych and Abigail Holstein Reviews by Jose Rivas and Stacey George Digital production by Xochitl Garcia and Sandy Roberts

Educator's Toolbox

Meet the writer.

About Sergio Estrada

Sergio Estrada is a physics and engineering teacher in El Paso, Texas, and a Science Friday Educator Collaborator. He teaches using a signature blend of real-world phenomena, applied physics, and enthusiasm. He hopes to inspire his students to change the world by learning how it works.

Explore More

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Hack your food with materials science as you use water-loving hydrogels to grow vegetables from scraps and make a batch of "hot" ice cream.

Change Up Your Homemade Ice Cream Recipe With Chemistry

Looking for dairy-free or low-sugar ice cream recipes? A chemist gives tips and substitutes to customize your favorite frozen treats.

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How to Make Hot Ice

Last Updated: January 15, 2023 Fact Checked

This article was reviewed by Anne Schmidt . Anne Schmidt is a Chemistry Instructor in Wisconsin. Anne has been teaching high school chemistry for over 20 years and is passionate about providing accessible and educational chemistry content. She has over 9,000 subscribers to her educational chemistry YouTube channel. She has presented at the American Association of Chemistry Teachers (AATC) and was an Adjunct General Chemistry Instructor at Northeast Wisconsin Technical College. Anne was published in the Journal of Chemical Education as a Co-Author, has an article in ChemEdX, and has presented twice and was published with the AACT. Anne has a BS in Chemistry from the University of Wisconsin, Oshkosh, and an MA in Secondary Education and Teaching from Viterbo University. There are 8 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 878,036 times.

How can ice be hot? When it's not ordinary ice. Using the same ingredients as a baking soda volcano, [1] X Research source you can create sodium acetate. By cooling this below its freezing point, you get a liquid that's ready to freeze at the slightest trigger. In the process of forming a solid crystal, it releases a burst of heat. And that's how you get "hot ice."

Making Sodium Acetate At Home

• Do not use a copper pot.

• You cannot use baking powder, which contains other chemicals that interfere with the process.

• This measurement assumes you're using 5% acetic acid, which is a common concentration for commercial vinegar. This doesn't need to be a precise measurement, though.

• If it does get very brown and cloudy, add a bit more vinegar and boil again.
• The sodium acetate starts out as "sodium acetate trihydrate," meaning it contains water. Once all the water around it is gone, those water molecules start to evaporate and the sodium acetate becomes "sodium acetate anhydrous," meaning "without water."

• It's a good idea to add 1 or 2 tablespoons (15–30 mL) of vinegar. The vinegar will help keep the solution in its aqueous state, instead of forming that crust again.

• If the liquid freezes during this stage, there might be a solid piece of crystal in it, or some other impurity. Add more vinegar, return to the stovetop, and try again. This is a difficult process, so it's rare that you'll get it on your first try.

• If this does not happen, there is a problem with your solution. Add more vinegar and boil again — or try the more reliable store-bought method below.

Using Store-Bought Sodium Acetate

• Sodium acetate is also sold as "sodium acetate anhydrous," and some vendors do not specify which form they mean. The instructions below cover both forms.

• If the sodium acetate does not melt, you've bought sodium acetate anhydrous. To turn it into sodium acetate trihydrate, add hot water while it's still in the boiling water bath. It will take about 2 mL water for every 3 grams of sodium acetate to fully dissolve the substance.
• Don't use all of your sodium acetate. You'll need a little for later.

• Other impurities can trigger the freezing if they happen to be the right shape. This means you can sometimes trigger it by touching it with a toothpick or your finger, but solid sodium acetate is the only reliable way.

Expert Q&A

• You can melt the solid "hot ice" and repeat the show by cooling it again. You can melt it easily in the microwave, since you no longer need to boil away any water. Thanks Helpful 4 Not Helpful 1
• You can make ice sculptures if you pour the solution onto a pinch of the solid crystals. The solution will turn into a solid when it comes in contact with the crystals, and will continue to solidify while you pour. The ice will soon tower up! Thanks Helpful 1 Not Helpful 1
• The home-made hot ice is more difficult to use and gives less impressive results than the store-bought method. If you have any problems with it, your best bet is to add more vinegar, boil away the water, and try again. Thanks Helpful 0 Not Helpful 0

• Do not touch the solution until it's cooled! Thanks Helpful 45 Not Helpful 13

Things You'll Need

• Sodium acetate trihydrate (or white vinegar and baking soda)
• Medium to large pot (steel or Pyrex)
• Clean container
• Ice bath (or refrigerator)

You Might Also Like

• ↑ http://www.rsc.org/learn-chemistry/resource/res00002026/bubble-volcanoes?cmpid=CMP00006775
• ↑ http://smile.cosi.org/cooking-with-chemistry-teacher-packet-and-classroom-activities.pdf#page=10
• ↑ https://youtu.be/g584hrAIMKc?t=40
• ↑ https://youtu.be/AedL_NCv1Pw?t=82
• ↑ https://www.raisingmemories.com/2014/05/homemade-hot-ice-sodium-acetate.html
• ↑ https://youtu.be/pzHiVGeevZE?t=60
• ↑ https://www.fleet.org.au/blog/hot-ice/
• https://www.raisingmemories.com/2014/05/homemade-hot-ice-sodium-acetate.html

About This Article

To make hot ice, combine baking soda and white vinegar in a large steel pot. When the mixture stops fizzing, put the pot on a stovetop and bring the mixture to a boil. Right when a crusty film starts to form on top of the mixture, turn the stovetop off. Scrape off the powdery crystals on the side of the pot with a spoon and put them in a separate container. Then, transfer the liquid mixture into a heat-resistant container, seal it shut, and chill it in an ice bath for 15 minutes. Finally, sprinkle some of the powdery crystals into the mixture to create hot ice! If you want to learn how to use store-bought sodium acetate for hot ice from our Biochemistry Ph.D. co-author, keep reading! Did this summary help you? Yes No

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Homemade Ice Cream in a Bag | STEAM Experiment for Kids

by Emily | Jun 20, 2019 | Recipes , STEAM Experiments , STEAM for Kids | 0 comments

In my opinion, there is no better sweet treat than ice cream on a hot summer day. My kids definitely agree and would eat ice cream all day everyday (probably in the winter too).

We’ve had our fair share of trips to the ice cream shop this summer, but I thought it would be fun to make ice cream at home with the kids and turn it into a STEAM activity too!

I saw an Instagram post about making ice cream in a bag from Systematic Motivation a few months ago and thought it was a great idea. We’re using her post as inspiration and a few Pintrest posts I found for the recipe in today’s experiment.

Our ice cream turned out great, and I know I’m going to have to keep lots of half-and-half on hand this summer because we are going to be making this a lot! I’ll get to the recipe and experiment soon, but first – the science!

Let’s talk about the STEAM concepts behind homemade ice cream

There are several STEAM principles involved in making this ice cream. In the science category there is a change of state and volume change due to bubbles involved, in the engineering category there is heat transfer, and in the math category there is measuring, counting, and adding ingredients.

I’ve talked about change of state several times on the blog, and I talked about it in most detail in my only other previous STEAM for Kids post that involved cooking: our Rice Krispies Treats experiment . If you like this post, I highly recommend checking out that post too! 🙂

Change of state happens when matter changes from liquid to gas or solid, and vise versa due to being heated or cooled. Water is always a great example because it changes state between liquid, solid and gas. Water is liquid at room temperature. If it is cooled to a temperature below freezing it becomes ice, a solid. If the ice is heated it will melt and change state back to a liquid, water. If the liquid water it is heated to above boiling point it changes steam, a gas. If the gas is cooled to room temperature it will condensate back to liquid water.

In this experiment heat transfer is occurring during our change of state. Ice absorbs energy in order to melt (this is an endothermic process). Heat is transferred from the cream solution to the ice, making the ice melt and the cream colder. Eventually as the ice absorbs more and more energy from the cream mixture it will begin to freeze.

This heat transfer is causing two changes of state: the ice is melting to become liquid water, and the cream mixture is freezing to become ice cream.

Salt lowers the freezing point of the ice. Since ice cream is not pure water (it contains fats and other ingredients), it needs a temperature lower than 32degF to freeze. Salt lowers the freezing point of ice from 32degF to 20degF in a 10% salt solution. Adding salt will make the ice take longer to melt, thus absorbing more energy from the ice cream mixture and freezing the mixture as it pulls away the heat.

The amount of salt added affects the quality of the ice cream. Too much salt can make the ice cream freeze too fast, causing it to be grainy, and too little salt can can make the ice cream freeze too slow, making it too soft.

Volume is the amount of space a three dimensional object occupies. In this experiment, when we make the ice cream the 1/2 cup liquid cream mixture turns into 1 cup of frozen ice cream. Why does the volume double?

The volume increases partially due to air being added into the mixture when we are tossing it around and shaking it. Also, when water (which is present in half-and-half) changes state from liquid to solid it expands due to the crystalline structure of the solid water molecule (think about when you put a full bottle of water in the freezer and it bursts or expands to the full limits of the bottle when frozen).

There are plenty of opportunities to practice basic math with your kids as you do this experiment. You can have your child help you measure and pour the ingredients into the bags. As you measure they will learn about the importance of accuracy in cooking and science, and how to read measurements on the measuring cup.

When adding ice to the gallon size bag, have your child count each cup as your add it into the bag to help them practice counting and adding skills. Keep adding until the gallon size bag is full and count how many cups it takes!

As you toss the bag around, try some math games. You can have them count how many times you can throw it back and forth with out dropping it! Keep going to see how high you can get (can you get to 20, 50, or 100?), starting over every time you drop it.

You can have a bag shaking competition. Count how many times each child can shake it before they need to stop. Who can do the most shakes at a time?

Vanilla Ice Cream in a Bag Recipe and Experiment

This is a fun summer (or anytime really…) STEAM activity for anyone from toddlers to adults. It’s simple, easy, fun, and delicious! You won’t be disappointed with this perfect summer treat.

Be sure to alway instruct your children to never put a plastic bag near their face, and especially never over their head. This is a suffocation hazard, so make sure you are observing young children at all times when you have empty plastic bags out.

The ice is very cold and prolonged exposure can cause freezer burn to your children’s hands. To avoid this, I recommend sharing the task of shaking the bag (each person only hold it for 30 seconds max), and using a towel and/or wearing gloves while handling the bag of ice.

Materials Needed:

• 1 Gallon size Ziplock freezer bag
• 1 Quart size Ziplock freezer bag
• 1/2 Cup half-and-half or whole milk
• 1 Tbs sugar
• 1 tsp vanilla extract
• 1/2 Cup salt (rock salt makes smoother ice cream)
• Ice (about 8-10 cups)
• Towel and/or gloves (optional, but recommended)

Note: It’s worth buying the brand-name Ziplock freezer bags for use in the experiment. They are stronger and more durable to hold up to the tossing and shaking involved to make the ice cream. I recommend double-bagging both the bags, because if the inner bag leaks, the ice cream is ruined (we’ve learned from experience!).

• Take out all your ingredients. Ask your child to form a hypothesis about this experiment. What will happen when we place these ingredients in a bag and shake it?

2. Add the half-and-half, sugar and vanilla (and any other flavors you like in your ice cream) to the quart size freezer bag, and tightly seal it.

3. Put the ice and salt inside the gallon size freezer bag.

4. Place the filled smaller bag inside the larger bag, and tightly seal the larger bag.

5. Vigorously shake and toss the bags for about 10 minutes, or until the ice cream is frozen. Try some of the counting games I described in the section above.

Remember, the bags have to be constantly moving the whole time for best results! We enjoyed tossing it around to each other, shaking it to the beat of music, and dancing with it.

On our first try we mostly tossed (and dropped) the bag. When it dropped it caused the outer bag and eventually the inner bag to leak, which ruined the ice cream.

6. Open the large bag and remove the smaller bag.

7. Dry the small bag (making sure to wipe off all salt, especially around the top so none gets into the ice cream)

8. Open the smaller bag and observe and discuss the change that happened to the ice cream (see discussion notes below in What Happened section).

9. Grab some spoons, dig in and enjoy your homemade ice cream!

You can eat it straight out of the bag or transfer to bowls to enjoy. We topped our vanilla ice cream with sprinkles. 🙂

What Happened:

The liquid half-and-half mixture changed state from liquid to solid, meanwhile the ice changed state from solid to liquid. Heat transfer occurred between the two substances – the ice melted because it absorbed energy from the cream mixture, turning the cream mixture into frozen ice cream.

You should have noticed that the volume of the ice cream is now close to 1 cup. The volume increased from 1/2 cream to 1 cup ice cream due to air bubbles being added as we tossed the bags around, and due to the ice crystals expanding as they formed in the ice cream.

We added salt to decrease the temperature at which the ice melts. The more salt you add, the faster the ice cream will freeze. But be careful, because if ice cream freezes too fast it is grainy. If it freezes too slow it will be soft. Try it making several batches with varying amounts of salt like they did on From Engineer To SAHM’s post .

This is a new family favorite activity for us that I am sure we will continue doing all summer long, and beyond! Nothing tastes better or is more fun than homemade ice cream that you get to shake and throw around in a bag to make!

Have you ever tried making homemade ice cream like this before? How did yours come out? Do you have any suggestions for tweaking the recipe or adding flavors?

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Hi, I’m Emily. I’m an engineer, mom, and wife. I encourage kids to love STEAM and motivate women to find personal happiness in their career and motherhood journeys.

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Some of the links below are affiliate links, which means that if you click on a product link I may receive compensation at no additional cost to you. I only link to products and pages I personally use and highly recommend. As an Amazon Associate I earn from qualifying purchases. Thank you for your support!