This photo is downriver from the dam on the Colorado River at Page, Arizona. Both the dam and the bridge support are curved. Why?


Often, as you watch a fireworks display, you will see a large burst that starts as one color, and then the entire burst changes to a different color. How do they do that?

Sail Fans

I got the idea for this experiment while driving around town. We were driving across the Bridge of Lions in St. Augustine, and I pointed out a sailboat that had a large fan-like propeller sticking up behind the sail. The propeller is attached to a generator, using the wind to recharge the batteries. We joked about it being a fan to provide wind if the breeze died down, which lead to a discussion about what would happen if you tried that. That lead to this experiment.

To find out what would happen if you did mount a big fan to blow on the sails, you will need:

Making a Solar Still

Imagine for a moment that you are stranded in the desert, and running short on water. Or imagine that you are in a boat far out at sea, surrounded by salt water, but no fresh water to drink. Is there any way you could use some science to get something to drink? Of course there is!