I picked up this in a toy shop. Students are fascinated by it and always wonder how it works. Once they learn about density, they figure it out pretty easily.
Eggs have an arch design in which compression forces are diverted from the top and bottom of the egg down to the sides. How much compression force can an egg take before it's smashed? Watch the video!
Two things I love: chocolate and science. This video shows you how to make chocolate pop rocks. Pop rocks was a crazy new candy when I was a kid. Put them in your mouth and let the crackling begin. Pop rocks is basically a mixture made when sugar and water are heated and then injected with carbon dioxide gas. The cooled mixture is the pop rocks. Put them into your mouth, the sugar disolves and the carbon dioxide gas gets released (the pop). Chocolate is a complex mixture of many ingredients, primarily sugar, cocoa butter, cocoa liquor, milk or milk powder (for milk chocolate), and vanilla. Chocolate can be melted and mixed in with other ingredients to make many different flavor combinations. Basically this demo shows how to properly melt (temper) milk chocolate and mix in flavorless pop rocks (called pastry rocks). The results are delicious pieces of chocolate that melt in your mouth which lead to a suprise crackling of the pastry rocks. Science topics that are covered include energy in phase changes, properties of mixtures, and crystalization (chocolate has to reach specific temperatures in the melting process so that cocoa butter crystals form evenly).