Phillip, my youngest is really into the hands on science experiments, always has been. When I saw this book, 101 Cool Science Experiments, I had to get it. I thought he would enjoy it and he has, we are having such a great time doing these quick, fun experiments. Most use things you already have around the house, and usually take only 20-30 minutes, instant gratification, we are learning so much, having fun, and really connecting.
Today we did one called "Hot Stuff"
small glass bottle
larger glass jar (has to be big enough to hold the smaller bottle)
You cut a long piece of string and tie each end around the neck of the small glass bottle. In that small glass bottle you put hot water and a few drops of food coloring. In the large glass jar you put cold water about 2/3 full. Then you use the loop of string to lower the glass bottle into the jar of cold water and watch what happens. It was too cool watching the hot, colored water drift out of the bottle, looked like smoke rising.
This isn't the same experiment (although pretty cool too) but explains what happens clearly, in case you want to replicate this at home:
When you heat up water, the molecules start moving around faster. They bounce off each other and move farther apart. Because they are farther apart a volume of hot water will have fewer molecules than the same volume of cold water. The hot water will weigh less and be less dense. When mixed with the cold water, the hot water will rise to the top, cold water will sink to the bottom.