Bus stop science

Wobble Do we use our eyes to balance? Find a safe place and stand on your tiptoes. Now shut your eyes. Does that make it trickier? You'll find that it does. This is because your brain uses what you can see, what your muscles are doing, and an organ inside your ear to keep you balanced. So if you take one of these away you start to wobble.

Finger Can you make your finger float in mid-air? Point your left and right index fingers towards each other so they’re almost touching. Now look through them at something in the distance and another finger will appear. The reason you can see a third finger is that the two images from your eyes only merge as a single sharp image for the point you are focussing on. Nearer or further objects (in this case your fingers) appear doubled and so a floating finger appears.

Tickle Is it possible to tickle yourself? Have a try. It’s harder than you think. Try stroking the roof of your mouth with your finger. It tickles because skin with no hair is sensitive to a light touch, whereas your brain tells your body not to react when you tickle yourself hard.

Pinch Can you pinch yourself without it hurting? Pinch the skin on your elbow as hard as you can. It barely hurts because different areas of your skin have different nerve endings. Tough skin, like that on elbows, has fewer pain detectors. Parts of your body at a higher risk from being damaged have more nerve endings, so are more sensitive.

Apple Can you eat an apple without tasting it? Hold your nose and take a bite out of an apple. It won’t taste of much. Your tongue can only taste five things: sweet, sour, bitter, salty and 'umami' - a savoury flavour found in meats. Your brain gets the rest of the flavour information from your sense of smell. Pinching your nose stops that information from getting through and forcing your brain to rely solely on the information from your tastebuds.