Do You Know?

1. How are buildings designed to withstand earthquakes?

2: Can a blood test reveal if one has cancer?

3. If your broken arm or leg has been in a plaster cast for a long time,
the limb feels weak when the plaster is removed. Why?

4: I understand that water boils at 100 degrees C and becomes vapour.
But why does water, in the form of falling rain, turn into vapour at a much
lower temperature after it strikes a hot surface, such as a paved road
during hot summer?

5: When electricity comes out of the plugpoint in the wall and through 
a lamp, where does the circuit loop complete ? Does the circuit go all 
the way back to the power plant?