Using a laser and some boiling water,

you can show why planets do not appear to twinkle in the night sky. 


Watch Video: 

Here's how to show your students why stars twinkle in the night sky!


Watch Video:

A not-all-together sane way of showing a class how retrograde motion works!


WATCH VIDEO

This demonstration shows how atmospheric scattering filters 

the colour of the sun during a sunset.


Watch Video:

 

Read more: Why Are Sunsets Red?

Three ways to show how the space between objects - like galaxies -

is slowly increasing due to the universal expansion. 


Watch Video: