Question: what is you favourite experiment?

Richard Simons answered on 13 Mar 2015:

Favourite to demo: Marshmallows in liquid nitrogen – the sugar crystalises and goes a weird mix of crunchy but light – super tasty 🙂

Favourite because of what it means: I’d say Isaac Newton’s work with prisms and different colours of light. At this time it wasn’t known that white light contained all the different colours, so when it was shone through a prism (which splits light by its wavelength) it was though that the clear glass prism was adding the colour to the white light. Newton showed that the colour was always in the light by splitting red from sunlight using a prism, and then shining that red light into another prism with the intention or reversing the process (red-white light), but it didn’t work. So Newton had created a very simple and elegant logic test to show that white light contained all colours of light. This work on separating the wavelengths of light from white is the basis of almost all of our astronomy methods (which use the colour of light from a start to determine its age, temperature, size and composition) and allowed for the development of quantum mechanics, which is the basis of our modern society (allowing the development of the semiconductors which power our computers, as well as the LEDs which I’m using for my project!)

Sorry for the long answer 😛
If you want some more information, here’s a great resource:
https://www.khanacademy.org/partner-content/mit-k12/mit-k12-physics/v/newtons-prism-experiment