If you look at the label of any food, you will probably find that it lists the Calorie content. Calories tell us how much energy you will get by consuming the food. How do scientists measure that energy?

I got the idea for this experiment while working on the rocks we collected recently. When we got home last weekend, we unloaded the 750 pounds of quartz crystals from our Arkansas trip onto the back patio. Then I left for Philadelphia to present some electricity shows. Today, I went out to unpack some of the boxes. We had wrapped the best crystals in newspaper, and all the newspaper that was exposed to sunlight had turned yellow. Cool! A chemical color change that happens fairly quickly, and is caused by exposure to light!

This experiment is a simple one, but it should make you think a bit. It might also change the way you think about egg shells.

One of the fun things about thinking up new science experiments is combining two or more old ideas into one new one. This time, we will combine the Dancing Raisins activity with the Cartesian Diver.

This experiment comes from my neighbors at the Malibu Creek State Park campground. While taking my morning walk, I heard a lady bragging to her husband that she started the campfire with only one match. That made me think of the fellow that I watched the night before as he poured two bottles of charcoal lighter fluid onto a pile of wood and still failed to get the fire going. He would pour on the liquid and get a huge blaze, which quickly died. How could the heat of one match work better than a gallon of blazing lighter fluid?