To explain the seasons to the boys when they asked about them, I got out an orange and a ping-pong ball.
'This orange is the sun,' I told them, 'and this ping-pong ball is the Earth. The Earth revolves around the sun'--here I moved my models, delighted to see the boys entranced, their wide eyes fixed on my substitute sun.
'Now--can you see how it goes?' I asked proudly, convinced I’d given them the gift of wonder.