I received an email from Emma Taylor of Accredited Online Colleges. On their blog they have a list of links they call Kitchen Chemistry: 100 Cool Food Science Experiments for Kids (and Cooks).
Science is awesome. Food is awesome. Blending the two together rocks faces off. Teachers and parents looking for some projects to introduce their students to the basic principles of chemistry, physics, biology and more can easily turn to the kitchen for inspiration. The following experiments vary when it comes to materials, difficulty levels and cost, so read them over thoroughly before making any commitments. Always practice proper safety precautions as well, most especially when tooling around with fire and acids and other lovely things.
The first 20 links go to experiments on Milk, Yogurt & Cheese. They include "DIY Yogurt: Making yogurt at home or in class makes for an excellent way to illustrate how helpful bacteria work — and all the good things they can do for the human body." and "Milk Glue: A brew of milk, vinegar and baking soda makes for a viable, sustainable adhesive for minor projects."
True, except for the yogurt one, the page is not really relevant to lactose intolerance, let alone avoiding milk. Well, tough. I like science. And the more you know about all aspects of milk, the better off you are. Besides, most kids and most people with LI can have most forms of dairy.
I'm going to reinforce the statement in the quoted paragraph. Because the links go to other websites, the quality, the presentation, and the age range of the experiments varies considerably. Check them out first before getting your kids involved. I haven't tried any of them and I can't vouch for their accuracy or practicality.