From Hugh Simpson-Wells
Discovering the reason behind the counter-intuitive effect of damage to the brain as it floats in its saline solution was brilliant work (5 April, p 21). However, there is a very simple experiment anyone can do to give the same fascinating result.
Buy a helium balloon with a ribbon, tie it down in a car (so that it isn’t touching a seat or the roof) and (with the windows closed) drive around – or preferably get someone else to drive around and make sure their view is not obscured and that they are concentrating on the road, not your balloon. Better still, do it on a bus.
When you accelerate, it moves forwards in the car, when you go around a left hand corner, it moves left and so on (the opposite of what happens to, say, something dangling from the roof). I have been fascinated by this for years, but never imagined there was a practical issue associated with it. And most people don’t understand why I drive with a balloon in the car.
Oxford, UK
