They are a teaching aid for showing students how the various planets revolve and rotate. With an Earth/Moon/Sun system model you can answer all these questions by just turning the handle.. 1  Why we have day and night.  What a year is.
1. Static electricity is caused by the build up of electrical charges on the surface of objects, while current electricity is a phenomenon from the flow of electrons along a conductor. 2. When objects are rubbed, a loss and/or gain of electrons occurs, which results in the phenomenon of static electricity.
Lightning is a sudden high-voltage discharge of electricity that occurs within a cloud, between clouds, or between a cloud and the ground. Globally, there are about 40 to 50 flashes of lightning every second, or nearly 1.4 billion flashes per year.