Shaking It Up With Science

My daughter loves Always Ice Cream (it was a TOS review earlier in the year)!  (If you are looking for a safe, fun, and educational online community for your girls, Always Ice Cream is it!)  One of the things I love best about her time spent on Always Ice Cream is she comes up with great ideas after watching videos on the site.    Last week it was how to make freezer bag ice cream.

This was a very fun activity, with neat science concepts involved.    I found a "formal" activity at Teachnet that guided me through the lesson with the kids.

Who knew that the Emperor Nero invented ice cream?  Those Romans were responsible for SO MANY things we have today.  

 We mixed milk, sugar, and vanilla in a quart size freezer bag.   Then, we added crushed ice and salt in a gallon size bag and put the quart sized bag inside of that.

Since the weather was great we did this activity outside... it was pretty messy, so being on the deck was convenient.     

The kids had to SHAKE their bags for at least 10 minutes -- even then the ice cream was a little slushy, but they loved it.   

We learned (thanks to Teachnet):

Just like we use salt on icy roads in the winter, salt mixed with ice in this case also causes the ice to melt. When salt comes into contact with ice, the freezing point of the ice is lowered. Water will normally freeze at 32 degrees F. A 10% salt solution freezes at 20 degrees F, and a 20% solution freezes at 2 degrees F. By lowering the temperature at which ice is frozen, we are able to create an environment in which the milk mixture can freeze at a temperature below 32 degrees F into ice cream.

We made some hypotheses about how we could make the ice cream thicker next time, and how we could also add cocoa powder or different types of extracts (peppermint, almond, etc...) to get different flavors. 


Next week I'm going to revisit this experiment and let the kids design their own ice cream flavor.  I also found some additional teaching resources here to delve further into the science of salt and water.   

All in all - a fun science activity that doubled as snack time!