Page 59 - BBC Knowledge - October 2017 IN

THE UNPOPPABLE

BALLOON
You don’t need a planet-sized brain to understand that a balloon plus
a sharp pointy object equals a big bang. But, when you up the ante, the sums
don’t always seem to add up, as this entertaining experiment shows…

YOU WILL NEED:
l A packet of drawing pins
l An inflated balloon (have one on
standby, just in case)

METHOD:
1. Scatter a handful of drawing pins evenly over a flat surface,
all pointing upwards.
2. Push an inflated balloon down onto the bed of pins.
3. Be amazed as it doesn’t pop!

WHAT’S GOING ON? eggs without them cracking! Place two large
We intuitively think that more spikes mean boxes of eggs on the floor, making sure all
more damage, but this isn’t true. One drawing the eggs are uncracked, about the same size
and with their ‘pointy’ ends facing down.
PHOTOGRAPH: JYOTHY KARAT pin would burst a balloon easily, but, when Put down some plastic sheeting if you’re Dr Stuart Farrimond is a science
the balloon is pressed down over many small
points, pressure is spread between each one,
worried about making a mess. Take off your
writer, presenter and educator,
shoes and socks and, with someone to help you
so you need to push down much harder before
any one point has the force to pierce the taut
balance, ease your weight down onto both sets
and hosts a weekly science
rubber. This principle also explains how circus
He has written The Science
possible.The lighter you are, the easier it will
performers can lie on a bed of nails.
of Cooking.
You can even test the theory by walking on of eggs, spreading your weight as evenly as segment on BBC Radio Wiltshire.
be, so perhaps this is one just for the kids…