St Mary's C of E (Aided) Primary School, Pulborough

Science - Whizz, bang, popcorn!

More experiments from Yrs 5 and 6 during Science Week - this time showing the effects of heat when applied to something...

We placed popcorn kernels into a sieve and watched as Mrs Parsons held them over the fire at Forest School. After a short while, we began to hear some mini explosions as the kernels started to puff out. We learnt that the kernels turned into popcorn as a result of a change in pressure. Inside each kernel is a tiny area of moist plant tissue surrounded by a hard shell, called a hull. When the kernels are heated up, the water inside them (a liquid) turns into steam (a gas) which causes a build-up of pressure inside them. When the hard shell cannot take the pressure any more, it goes 'pop' and turns into the white fluffy pieces of popcorn that we eat.