Trees can weigh hundreds or even thousands of tons, but where do they get this mass from? A few common answers are: the soil, water, and sunlight. But the truth is the vast majority of a dry tree’s mass comes from the air – it originated as carbon dioxide
Aerogels are the world’s lightest (least dense) solids. They are also excellent thermal insulators and have been used in numerous Mars missions and the Stardust comet particle-return mission. The focus of this video is silica aerogels, though graphene aerogels are now technically the lightest. Continue reading
When physics students first learn about Newton’s law and momentum, they get the impression that it’s all about mass. If that’s true, how can mass-less light have momentum? It’s because mass isn’t actually required.
The kilogram, mole, kelvin, and ampere will be redefined by physical constants. Continue reading
Contributed by: Derek Totten
…a good balance of science and fun!
- Simple machines help objects to move.
- Simple machines and mechanisms make life easier and/or more enjoyable for humans.
Curriculum Connection: Grade 3: Structures and Mechanisms Continue reading
You botched your forward double somersault and biffed it hard on the water. Why does it have to hurt so bad? Continue reading
I have been obsessed with measurement for a long time and I’m not sure quite how it happened. The world’s roundest object played a role in this. I guess I’m just fascinated by how difficult it is to pin down a quantity like a kilogram. Continue reading