Test the assertion that we all love chocolate and design a questionnaire that will reveal likes and dislikes. Produce bar charts and graphs to illustrate your findings, replacing the usual pie chart with a chocolate slab design.
Set up a chocolate tasting experiment to discover the most popular "straight" chocolate. Many interesting varieties can be obtained from the Chocolate Society such as Guanaja, a very dark and strong chocolate, Caraibe, a single bean chocolate and Ivoire, a white chocolate.
Make some chocolate-based items using simple recipes such as a chocolate loaf, chocolate babycakes or chocolate macaroons (Nigella Lawson recipes are perfect). Share them with other classes.
Watch some chocolate advertisements. What imagery is used to promote a desire for chocolate? Produce advertisements for different audiences. Make a presentation to an imaginary company you hope will market a chocolate product you've made. What is it called? What does it contain? How is it different from items already available? Design a wrapper for it and write a promotional slogan.
Set up an experiment to discover chocolate's melting temperature. Show how the melting point is just below body temperature, meaning that chocolate will melt immediately it is placed in the mouth.