A Hologram for All Theories

When I am not editing Holography News for Reconnaissance International, I volunteer as an online maths and science tutor. Nowadays, I tutor students from age 15 to 18, but I have previously taught children as young as 11.

One of the strangest experiences I am constantly amazed by is the ease with which students accept the idea of gravity. In the UK, the concept of gravity is introduced through the story of Sir Isaac Newton (1642-1727) sitting underneath a tree, when suddenly, without any apparent projectile being thrown, an apple falls from the tree and lands on his head.

Its gravity – stupid!

And that’s it. From that point on if you ask a child what is the non-contact force that acts between two masses at a distance, you should get the answer ‘gravity’ – that is if the student has been paying attention! If you get a question in an exam ‘what is the force that holds the Earth in orbit around the Sun’ – you should answer ‘gravity’: ‘what holds a person to the surface of the Earth’ – answer ‘gravity’ (although I did get one answer from a student that it is the force of ‘atmospheric pressure’ pressing us to the surface which got me thinking that it wasn’t such a silly counter-hypothesis – but even then it is gravity that holds the atmosphere to the Earth).