TABLE OF CONTENTS This chapter describes a number of experiments on or relating to ice cream. The first seven illustrate some of the physical phenomena that have been discussed in the preceding chapters. Experiment 8 gives two recipes for ice cream mix and Experiments 9 12 demonstrate four different methods of freezing, aeration and agitation to turn the mix into ice cream. Experiment 13 describes how to make water ices. The final four describe some methods of evaluating the results. Most of the experiments use only standard kitchen equipment, but a few need more specialized laboratory apparatus. In carrying out these experiments the appropriate safety precautions must be taken, especially when using glass, heat or liquid nitrogen. Making ice cream in a classroom or your kitchen not only allows you to test the underlying scientific principles, but also to eat the results, provided of course that the ice cream has been prepared hygienically.
Aim:
To show how your freezer works.
Apparatus:
A balloon
Procedure:
Your freezer works by compressing a gas so that it liquefies. The gas warms up as it is compressed, and this heat is lost to the outside via the tubes at the back. Once the liquefied gas has cooled down to room temperature it is allowed to expand, and in doing so takes in heat from the freezer compartment. You can demonstrate this effect with an uninflated balloon. First hold the balloon at either end and feel its temperature by touching it to your upper...
