Find More  Science Experiments
- Your Favorite Drink (Soda, orange juice, lemonade, etc.)
- Quart-size zip-lock bag
- Gallon-size zip-lock bag
- 2 cups ice
- 1/4 cup salt
Fill the quart size bag with your favorite drink and zip it closed. HINT: Make sure the bag is zipped really good or your slushie will taste bad when some of the salt leaks into your bag. Put the quart size bag inside the gallon bag. Add the ice and salt to the gallon bag. Zip the gallon size bag closed. Now shake the bag a lot – even play catch with it…gently. In about 15 minutes you will feel the ingredients in the quart size bag starting to firm up. What started out as a liquid is changing to a solid. When it feels done take the quart size bag out of the gallon size bag. Rinse it off good in clean water. Then open the bag, squeeze the slushie into a glass and enjoy!
TIP: It’s OK for a dog to lick the ice, it won’t be in your drink anyway. Tip for the dog…lick the ice BEFORE the salt goes in!
And if you’re feeling like something with a few more ingredients, try this, ziploc bag ice cream!:
Your favorite drink is a liquid until it gets really cold. Your liquid drink would be pretty good with ice just floating in it…the ice cubes would make the drink colder…but the ice cubes would not make the drink freeze into a slushie.
Ice forms when the temperature of water is 32 degrees or colder. You don’t want the ice cubes to melt IN your drink, you want your DRINK to turn slushie. In order to make your drink turn slushie you have to get it really cold. Salt lowers the melting point of water. To make a slushie you want the temperature around the bag of your favorite drink to be lower than 32 degrees so your drink will freeze. When you add salt to the ice cubes you lower the melting point of the ice cubes by several degrees. The ice cubes stay colder, longer – long enough to turn your drink slushie. Your salt/ice mixture will make your slushie faster than your freezer! That secret is the catalyst – the salt.
Science Experiment Idea: Make 3 different quart size bags each filled with the exact same amount of your favorite drink. Fill each of three gallon size bag with the exact same number of ice cubes. Add 1/8 cup of salt to the first gallon size bag and label it with a sharpie, “1/8”. Add 1/4 cup of salt to the second gallon size bag and label it “1/4”. Add 1/3 cup of salt to the third gallon size bag and label it “1/3”. Have a couple friends help you shake and smoosh the bags to make the slushies. Time how long it takes each of the bags to turn into a slushie. Which amount of salt makes a slushie the fastest?
Here are some websites and books that will help you understand the thermodynamics of slushies…and ice cream too!
- PBS Kids: Fetch Ice Cream Shake 
Words to Know:
Heat – To increase in temperature.
Melting Point – The temperature at which a substance will change from a solid to a liquid.
Thermodynamics – The study of the transfer of heat.
Catalyst – Something that makes a change happen faster.