This is a fun project to do with students or with the children in your family on a vacation day. I used this as a Science activity with my seventh grade students in Hawaii. The instructions and ingredients are simple enough that this ice cream project can also be used with younger age children. My students did this particular ice cream activity outside to minimize the mess. As an added bonus students can bring their favorite ice cream topping in a ziploc bag to add into the ice cream mixture as it is firming up.
Here are links to three options for Homemade Ice Cream in a Bag.
http://familyfun.go.com/recipes/homemade-ice-cream-in-a-bag-684806/ (This one uses half and half.)
http://homeparents.about.com/od/recipesandcrafts/r/zip_icecream.htm (This one uses milk rather than half and half.)
http://www.teachnet.com/lesson/science/icecream051999.html (This one offers the option of making the ice cream in a coffee can.)
Ingredients and Materials to Make Ice Cream in a Bag
1 C half and half
2 Tbsp sugar
1/2 tsp vanilla
1/2 C rock salt
ziploc bags (One gallon size bag and one quart size bag will be needed for each recipe made)
permanent marker to put names on the ice cream bags
Divide your ice cream mixture into individual ziploc bags and then place the sealed bag of ice cream mixture into a larger gallon sized bag filled partially with ice. Add rock salt to the outer bag and seal it carefully. Have the students toss the ziploc bag back and forth within their hands, using the towels as needed, when the bags become too cold. I remember this project taking about 10-15 minutes. We then took the ice cream out of the exterior bag and placed it in the freezer for a firmer freeze. When you are taking the ice cream bag out of the larger bag to put it in the freezer wipe it off and then add in your individual ice cream toppings. When the ice cream is firm the kids can eat it directly from their individual bags which have been labeled with their name.