Students are able to turn milk into mozzarella cheese in one class period.  This is a great way to demonstrate lactic acid fermentation and the food making process- one of the original biotechnology examples!  Rennet can be purchased online, or you can talk to your local cheese plant to see if they will donate the small amount you will need.  Other ingredients are supplies can easily be purchased in your local grocery store.  

This video is a good resource to keep the student's attention and give an overview of Wisconsin facts  that are leaned in 4th grade to meet the standards.

" This seminar is designed to be an experimental and hands-on approach to applied chemistry (as seen in cooking). Cooking may be the oldest and most widespread application of chemistry and recipes may be the oldest practical result of chemical research. We shall do some cooking experiments to illustrate some chemical principles, including extraction, denaturation, and phase changes."