Mirrors are made from a piece of glass which is backed with a very thin layer of shiny metal, usually silver. When light hits the shiny surface it is reflected at a very precise angle. Because there are no dips or grooves in the silver layer all light beams are reflected in the same way and so a coherent image will form. If the glass is curved the image will be distorted, making a person look taller or smaller, thinner or fatter. When you look at yourself in the concave part of a spoon (the bit that holds your food!) you appear to be upside down - why is this? Think about what is happening to light from your forehead and light from your chin. Light from your forehead travels straight to the spoon, but because of the curvature of the spoon, it is reflected downwards. Similarly light from your chin strikes the spoon and is reflected upwards. These light rays cross at a point quite close to the spoon and then carry on towards you – chin light heading up and forehead light heading down! When this light hits your eyes you see your image upside down. All that Glitters … sparkles. Why? Glitter sparkles because it is made from lots of very tiny mirroring pieces of plastic. The light bounces off each piece in a different direction, so sometimes light will bounce back straight into your eyes and sometimes it will bounce back in a different direction. As you – or the glittery object - moves, the different light beams will hit your eyes, giving the effect of a shimmering surface.

	Make your own periscope
	Periscopes can be used to see round corners and over high objects. Submarines use periscopes to see above the water without having to surface and give themselves away. To make a periscope you need a long thin box (which can be made from two – clean - orange juice cartons, minus the ends, taped together). And two square mirrors – the same size if possible.
	Cut a hole in the side of the box, right at the very end. The hole should be a similar size to your mirrors.
	Next cut a hole in the side of the box at the other end, on the opposite side of the box as your original hole. Again this should be about the size of your mirrors.
	The tricky bit is to insert the mirrors. The mirroring surface needs to face outwards and it should sit at an angle of 45 degrees to the hole. Tape the first mirror into place.
	The other mirror goes in the other hole, again facing outwards and at an angle of 45 degrees to the hole. This way light hits the top mirror, is reflected down the box, hitting the second mirror and then is reflected out the bottom end.
	You may need to adjust each mirror slightly to make sure you can see through the periscope properly.