TOYS TOYS TOYS!
TOY #2: GEYSER!
Principle: This toy is based on the laws for gasses under pressure.

How it works:
GEYSER! would be an interactive board game. The setup is a waterproof board, where players travel around a path in Yellowstone National Park. In the center would be the GEYSER! which is a model of Old Faithful.
As players circle the board, they encounter "Hazards", (i.e. "Park bear ATTACKS!!) and for each hazard would have to pump the tree. The tree is actually designed the same as the pumping mechanism of a super soaker.
Some squares would be labeled "GEYSER!",where they would have to press the trigger button. If the GEYSER! had been pumped enough, the board would shoot out water, and that player would loose.
The object of the game would be to make it around the board without setting off the GEYSER!

1. As you pump the tree, it increases the pressure in the bottle(3)
2. When you press the trigger (2), the pressure in the bottle is greater than the air outside, it wants to reach equilibrium and pushes water out of the way (5).
Construction Cost:
This game would be slightly expensive. The pumping system included and all the pieces would make it more expensive than a Super-Soaker, ($20). So my estimation would be $25-30. All materials are plastic.
Durability:
I am unsure about the durability due to the number of moving and workable parts. But again since this toy is designed for older children, I expect the wear and tear to be less.
Safety:
I set the age on this toy at 8+. This is due to small pieces and dealing with liquids. If this is adhered to, I find the toy very safe.
Stacie Hogya smh@andrew.cmu.edu