Grade school was fun, do you remember? Most of us would be lucky to remember a single thing from high-school or college algebra. Did you ever make a blue tornado? It is often a vivid memory for many people, but in case you didn't or don't remember, you can teach your kids about the earth's rotation and make a fun "toy" at the same time.
Even if you don't have kids, feel free to try this fun activity (even by yourself). Tornadoes aren't usually blue (not that I shake hands with them and ask about it), and you can make yours whatever color you want, but blue shows the tornado's vortex quite vividly, as you can see.
A tornado forms between a certain type of thunderstorm and the ground, and the swirling spiral forms due to things called updrafts and many other complex factors that I don't even understand completed. To read more on tornadoes and why they form, visit HowStuffWorks
5-10 drops of food coloring (blue or green work best)
1 liter of water (approx half a bottle, doesn't have to be measured)
2 clear or green soda bottles (2 liter size, clear work the best, but green bottles can be used as well)
duct tape or packing tape
10 minutes or less
Rip all the labels off your soda bottles, and rinse them out
Drop in about 5-10 drops of food coloring into one bottle, then fill it half way up with water. Putting the coloring in first will make the water mix it together for you.
Flip the second bottle upside down and match up the neck of this bottle with the neck on the bottle that contains the blue water.
Carefully tape the bottles together, being sure to get a good seal by laying the tape flat across the joint, and sealing any potential leaks before you attempt to use the blue tornado. You may want to put a few layers of tape on the joint, but just enough until you feel like it will hold.
Test it out by flipping the entire "hourglass" over on a cleanable surface, like a bathtub or kitchen floor. If it doesn't leak just from flipping it over, you are home free! If it does leak, you may need to dry the joint and
Gather some small children for extra fun, or just enjoy this yourself, then flip it over and swirl the bottles in a circular motion to get the vortex spinning. It will spin very quickly and empty the bottle fast. It is a good idea to let kids help you swirl it, which gets their imaginative juices flowing (no pun intended), but be sure to hold onto the hourglass right around the center where the joint is, especially if kids help. This will ensure the joint doesn't burst or leak, and will help support all the weight that is in the top bottle when the liquid is present.
Some stores actually sell a small plastic object (a connector for two bottles) you can screw the two bottles into, and have the same effect, but where is the fun in that?
This simple activity can be supplemented by scientific info from the Internet, or can be changed in different ways to further discuss tornadoes and weather with kids, so have fun with it.