From Lucian McLellan
Sebastian Hayes asks science teachers, “What evidence do I see around me of relativity or quantum mechanics?” (31 January, p 25). I whirl round a bucket of water on a rope over my school’s laptop. Relativity shows that gravity and centripetal acceleration are giving and taking in the same currency: the water stays in and the laptop is saved.
Quantised energy in photons and in electron levels in atoms mean that when I sprinkle black copper oxide into a metal dustbin full of methane and light it, the metre-wide fireball that roars out is green. Red copper (I) oxide gives the same green flame. The reverse process to the bin fire prints photos, puts energy into plants (crisps burn nicely to prove it) and makes retinal cells fire; if this New Scientist is brought to you in colour, that shows the world is quantised.
Bristol, UK
