In this article we investigate the force of friction which opposes the forward motion of objects; we look at the force that needs to be applied to an object before friction can be overcome and forward motion can occur. We explain static and kinetic friction, how friction comes in pairs and represents the interaction between two different surfaces; what happens when a surface is frictionless, how friction can help or harm.
Early theories about the motion of falling objects; characteristics of objects in freefall; how the shape,cross sectional area and mass of different objects affect the speed of objects in freefall; the hammer and feather experiment as carried out on the Moon in 1971; two different types of freefall ; Felix Baumgartner’s incredible jump from the edge of space; reaching terminal velocity.
How amber is fossilized tree resin; how the ancient Greek philosopher Thalus of Miletes was the first recorded person to observe static electricity in action in 600BC; how he used amber in an ancient static electricity experiment; the meaning of the ‘triboelectric’ series; what the triboelectric series tells us; which materials have a tendency to become positively or negatively charged.
The legend of Magnes and the discovery of lodestone; ancient superstitions about lodestone; early compasses and their limitations; a description of a sixteenth century maritime compass; explanation of symbols used on a sixteenth century maritime compass including symbols used to indicate north and east; original science project ideas for making colorful compass roses.