How to Make In stant Ice Cream at Home

 Overview 

The Homemade Ice Cream is a super fun child-parent interactive stem activity. After you have fun with this science experiment, you can also eat up your outcome, ice cream. Can not wait to get started? Let’s go.

Age: 5+     Time: <30mins

 Safety 

1. Adult supervision.
2. Be careful with the fragile glassware.
3. Wear protective gloves and goggles.
4. Be careful frostbite.

 Materials list 

• 60g Cream
• 30g Pure milk
• 10g Sugar 
• 0.5g Vanilla Flavor
• 1200g Crushed ice
• 400g Rock salt (Rock salt is better than normal salt here)
• Small zip lock bag
• Large zip lock bag
• Insulation gloves

 Instruction 

Step 1/4 – Choose the ingredients to make the ice cream according to your own taste. The formula used in this experiment is 60g cream, 30g pure milk, 10g sugar, and 0.5g vanilla extract. Put the mixture into the small zip lock bag.

Step 2/4 – Push as much air out of the bag as possible before sealing it tightly. Protect it with another bag of the same size.

Step 3/4 – Put 900g of crushed ice and 300g of salt in a big ziplock and shake it a little.

Step 4/4 – Put the first bag into the second bag, push out the air as well, and shake the bag until the ice cream is hard enough. It usually needs to be shaken for 15-20 minutes. And then enjoy your self-brand ice cream.

 Troubleshooting 

Why is the ice cream not solidified?

– There is not enough salt or ice added. The ratio ice cube mass: salt mass = 3:1 is perfect. It probably needs to be shaken for a longer time.

 Question to ask 

1. What makes the ice cream solidify?
2. Why do you need to shake the bag?
3. Is the principle of making ice cream the same as the ice cream made in a refrigerator?

 Scientific description 

Both the ice cream made by the refrigerator and the ice cream made by the ice cream machine is formed by freezing the ice cream solution (milk, cream, and other materials). The same is true for the ice cream formation process in this experiment. Salt causes the ice to melt and in this process, it absorbs the heat about so that the temperature goes down. NaCl in the rock salt can lower the freezing point of water, that is, lower the temperature of the water when freezing.  Normal water will freeze at 0 °C under standard atmospheric pressure while the saltwater will freeze at a lower temperature. The more salt in the water, the lower the freezing point. The freezing point of the 10% NaCl-water solution is -6.56 °C, and 20% NaCl-water solution is -16.46 °C. Therefore, when the rock salt is sprinkled on the ice, the rock salt dissolves, so that the ice begins to melt due to the lower freezing point. The melting cubes absorb heat from the surrounding environment, including the ice cream solution contained in the ziplock bag. Thereby it freezes the ice cream solution to form ice cream. The same principle applies to sprinkle salt to melt the ice on the road in winter.

 Extensions 

Instead of shaking the bag, you can replace the bag with a small size iron or plastic can, so that it is more interesting. You can kick it like a soccer as well as throw it like a volleyball. I am sure you will have fun with it.

 Disposal 

Pour the liquid with water into the sink, and do not forget washing what you have used.