Where would we be without light? In the dark, that's where... Without light, life would never have evolved on Earth. And without colour… well, Lawrence Llewellyn-Bowen would be out of a job for a start. The question is: are you switched-on enough to get 10 out of 10 in the following quiz? If so, you could win one of three groovitating Double Disco Balls from the Gadget Shop. And never be short of a party atmosphere again! Hit the Lights! GOOD LUCK! >>>
	01 How does a mirror work? It is a porthole into a parallel universe where everything is identical but the opposite way round. It is like a webcam that instantly projects the picture it takes. The light bouncing off you and other objects placed in front of the mirror hits the mirror's surface and is reflected back into your eyes. Mirrors create an image of everything alive, which is why Dracula has no reflection in a mirror. 02 Why does a pencil appear to bend when you put it in a glass of water? The pencil quickly absorbs the water and it becomes wobbly – you can see this by moving it around. The light reflected off the pencil in the water is bent as it passes from water to air. The bending is caused by the light travelling more slowly in water than in air. The water gives the light a push so it gets to our eyes quicker. This makes the bit of the pencil in the water seem nearer and therefore the pencil appears bent. The pencil is made of wood so the end in the water starts to float towards the surface. 03 Where does all the light go when you turn a light bulb off? The light bulb sucks the light back in to conserve energy – energy saving light bulbs do this much faster than normal. All the light quickly escapes from the room through the gap beneath the door. Light waves are all connected like strings to the light bulb when it is switched on. When the bulb is switched off it is like cutting the string and all the light waves fall to the floor. All the surfaces in the room rapidly absorb light. With the light bulb off no new light is given out so the room goes dark. 04 Why are soap bubbles always white no matter what colour the soap? Soap is designed to wash colour away - add water and it disappears. All colours of light are reflected by the bubbles, which are two thin films of soap with water in between. All the colours of light add up to give white light which is why the soap bubble appears to be white. Soap contains acid which burns away all colour when put in contact with skin. All soap is really white but there is a thin plastic film around the soap bar to make it look coloured. This plastic film sticks to the bar even when some of the soap is used up when you wash your hands. 05 Which one of the following is not an optical instrument? A picoscope. A microscope. An endoscope. A telescope. 06 What does LASER stand for? Light And Sound Energy Reduction. Light Amplified Signal that Emits Red. Light Amplification by Stimulated Emission of Radiation. Loud Amplified Sound at an Enormous Rate. 07 A fire can be started using a magnifying glass. Why? The glass can be rubbed with a stick and the sparks created can start a fire. Light and heat is focused to a specific point called the focal point and this heat can make dried leaves or paper ignite. Magnifying glasses have a battery in them to keep the glass warm. Sometimes the glass can overheat and start a fire. Magnifying glasses suck the light from objects making them appear bigger – but they also suck the coldness from an object too. If they are used for long enough all cold will be removed and the object becomes hot enough to burst into flames. 08 Fibre optics are used in communications – what else are they used for? For keeping an eye on babies while they are asleep. Having a look to see what is in your stomach. Estimating the population numbers of tiny insects called shinies. Cutting through incredibly soft cheese. 09 Who will only see in 2D rather than 3D? Anyone older than 111 years of age. A one-eyed pirate. Dalmatian dogs. Three-toed sloths. 10 For humans, the spectrum of visible light is made up of all the colours we see in a rainbow from red to violet. Bees are able to see a different spectrum of light. What would a rainbow look like to a bee? They would see a rainbow as red, orange and yellow. They only see the colours of bright flowers and each other’s stripy bodies. They would see a rainbow as green, blue, indigo, violet and ultraviolet. Green is the most important colour to them as they need to recognise plants, but they can't see red light. They would see a rainbow similar to the way we do, red, orange, yellow, green, blue, indigo and violet but they also see ultraviolet. They would see a rainbow the opposite way around; they see red where we see violet and violet where we see red. Back to Quizzes & Competitions