If the light source is too far way form the photovoltaic cell then not enough energy is converted to power the fan that blows the ball up the tube. If the light source is too close it wont work either, this is because the entire surface of the photovoltaic cell must receive the light. Atmospheric conditions also play a role in harnessing solar energy, this is demonstrated by the slightly opaque film that can be slid back and forth simulating cloud cover. Natural Forces Turning the knobs on Magnetic Circus brings the exhibit to life. Visitors manipulate magnets to get the circus going.
Magnets move a cart-wheeling clown, roll out the barrels, ring bells and more.
The colored magnets make it easy for visitors to identify polarities and recognize attraction and repulsion. When first sizing up the Velocity Tracks , visitors make a prediction of which of the tracks they think will be fastest and why. But not too long because now the brightly colored balls are rolling. Keeping an eye on the finish line, visitors determine if their predictions were correct and ponder potential versus kinetic energy. Round and round and round it goes.