Escape The Science Lab

Hang a bar magnet on a piece of thread and wait until it stops moving. One end will eventually point to the north pole of the Earth. This happens because the earth is a giant magnet, and your magnet is lining up with the Earth's magnetic field, which surrounds our planet like a giant bubble and allows us to find our way around. A magnetic field is an invisible force field that surrounds magnets. Other magnets and some metals are influenced if they come into the magnetic field. The magnetic field around a bar magnet is called a butterfly diagram. Perhaps you can see why. The field is why a magnet will stick to a fridge, or two magnets may push each other away. Each magnet’s magnetic field interacts with the other’s, causing attraction or repulsion.  The ends of a magnet are called poles. One end is called the north-seeking pole, and the other is the south-seeking pole. We usually shorten these to north and south. Put two poles that are the same together; they will repel. A north and...

  Ever wondered how a rainbow forms? Raindrops act like a prism and split the light into the colours of the visible spectrum. The splitting is called dispersion. The splitting is caused by refraction. That's not the whole story though. After entering the raindrop, the light is reflected off the back surface. It then travels out of the front of the drop, refracting again at the boundary. If, when this light leaves the raindrop, it happens to travel to your eyes, you see the familiar bow in the sky. What this means is that nobody sees the same rainbow as you. A friend stood next to you sees the light that has been refracted in their direction. Ever heard of the famous double rainbow? They are formed when the light reflects twice inside the raindrop. Have you ever noticed that the colours in the second rainbow are reversed? The diagram above shows why. Other affects you may notice when you see a good rainbow are supernumerary bows (green and magenta bows underneath the other bows. The...

  The splitting of light when it travels into a prism is called dispersion. The splitting is caused by refraction. Refraction occurs when light moves from one material to another. Each wavelength of light is refracted through a different angle, so the colours separate. One of the most famous effects of dispersion is the rainbow. These are always good to see, but there are many more atmospheric light effects to look out for. In this image, you can see a halo around the sun, two sundogs (parhelia) on the left and right of the halo, an upper tangent arc (on top of the halo), a parhelic arc (going through the two sundogs) and infralateral arcs (far left and right of the image). These are all caused by ice crystals refracting light. Look  here  for some other light effects you may see in the atmosphere. I would really like to see the spooky Brocken Spectre. The light really is fantastic. Take up my escape challenge by clicking on the image below.