Over the weekend, I was out with my eldest daughter Lily when we came to a pedestrian crossing. She pressed the button, waited for the green man to flash up and then we crossed. As we were crossing she asked me how blind people know when to cross if there isn't a noise.

Would you believe it? I knew the answer!!

In May this year there was an article on this very subject on the BBC News website. Under the pedestrian crossing is a 'secret button'. A small cone with a ridged surface that spins when the green man comes on. This allows blind people to know when to cross.

Not all pedestrian crossings 'bleep'. For example, when there are two together in case anyone gets confused.

I think this is a fantastic example to show students that sometimes the most simple and smallest innovations can be life changing.

A link to the article is here.