Why do we weigh less in water? plus 9 more videos..

Archimedes Principle - Why do we weigh less in water?
Newton's Third Law of Motion - Why does a swimmer push the water backward?
Convex Mirror - Why is a convex mirror used as a rear-view mirror?
Heat - Why do woolen clothes keep us warm?
Atmospheric Refraction - Why do stars seem higher than they actually are?
Gravitational Force - Why do you weigh less on the moon?
Pressure - Why is it difficult to cut with a blunt knife?
Density - Why do firemen crawl in smoke filled rooms?
Ultrasound - Why is ultrasound used in sonar?
Refraction of Light - Why does a pencil look bent in water?