Nina investigates why people have two ears, with the help of Belle, her hearing neuron.

Experimenters Eve, Finlay and Lana visit Nina in her lab. They do a listening experiment and discover that in a noisy place, when there are lots of different sounds happening at once, it is easier to make out what someone is saying when you use both ears.

Next the children go outside and prepare to cross the road safely with Nina. They find out that it is important to listen carefully when crossing a road as you can sometimes hear a car before you can see it. And they notice that they can also hear which direction the car noise is coming from.

Back in the lab, they do an experiment and discover that the brain is able to work out where a noise is coming from because people have two ears. Nina explains that this is because a sound reaches the ear closest to it first. Show less