## Ice cream science:  Learn some chemistry while cooling off

### Learn chemistry with your youth while cooling off this summer with ice cream science.

When it is a hot and humid summer day, ice cream always seems to be a treat enjoyed by everyone.  Michigan State University Extension recommends using this perfect opportunity to teach some basic chemistry to your youth while cooling off with ice cream. Do not use a fancy ice cream maker; make it interesting, educational and fun by using a recipe utilizing a Ziploc bag.

Servings: 1

• 1 cup of milk or half-and-half
• 1-2 tablespoons sugar  (1 teaspoon will be less sweet)
• 1 or 1/2 teaspoon vanilla extract
• 1 pint-size Ziploc bag
• 1 tablespoon salt or 1/2 cup salt
• The bigger the granules, the better. Rock salt works the best, but table salt works.
• The amount of salt used depends on the bag or can size.
• Ice – large or small cubes – enough to fill the bag or can at least half way
• 1 gallon-size Ziploc bag, coffee can or other round metal can

Set the educational stage by explaining and showing the difference between liquids and solids.  As you put the ingredients into the Ziploc bag explain how the milk and vanilla are liquids and the sugar is a solid.  Next you can explain how ice changes from a liquid to a solid as you put the ice and the salt into the can or larger Ziploc bag.  Put the tightly sealed bag of ingredients into the can or bag.  The fun and educational conversation can continue as the can is rolled back and forth. If using Ziploc bags, shake them for at least 10 to15 minutes or feels hardened.  Will the liquid mixture turn into ice cream?  Will it become a solid when it is cold and a liquid when it is warm?  Did the metal can make a difference and work better than a bag? Was mathematics used in the measuring process?  Do the amounts matter?  Why does salt go with the ice cubes?   After this inquiry based conversation enjoy the rewards of your work.  You can even try a scientific ice cream experiment by being creative and adding other ingredients to your treat such as fruits, chocolate chips, etc.  See which combination tastes the best.

Skip the long lines at the ice cream stand, cranking on the ice cream maker handle or staring at the electric ice cream maker.  Have fun and learn something new making your own soft serve ice cream.   You can find many recipes online for homemade ice cream. Some great examples include ice cream science on the education.com website, Disney ice cream in a bag or the Best Ice-cream Recipes Gallery.  Stay cool this summer and have fun with science!