How light travels

Light is a form of electromagnetic radiation. It travels as waves passing through space which has no air. The light waves have a wavelength and what we call light is the visible part of these waves. Do you know from where we get light?Almost all the light and energy reaching the Earth actually comes from the Sun which is continuously going through a thermonuclear reaction like a huge hydrogen bomb. Light generally travels in a straight line. However,it can be made to bend around curves and angles by using optic fibres because the outer surface of these fibres neglects light. So, when light is shone on one end of a bundle of optic fibres it passes along the fibres reflecting from the side as they curve and eventually emerging at the far end.

What happens when a star dies

Stars make the energy they need to exist by converting hydrogen into helium. When the hydrogen is used up they then use any other nuclear energy. However, once they exhaust these vast supplies of nuclear energy they die. And when they die they either blow up,shrink,go cold or become a black hole

Just how long it takes for a star to reach its point of death depends on each individual star. There are some big stars that have masses of nuclear fuel but they live fast and die young.

The smallest stars have less nuclear fuel than most big stars but they live slow and long lives.

Who the Vikings were

The Vikings were known as the raiders from the sea because they were warriors who terrorised the people of Europe.

The countries we call Scandinavia today: Norway, Sweden and Denmark were their homeland.

The word Viking comes from the old Scandinavian word Vik which means a narrow bay beside the sea. That's where the Vikings lived, ready to set off on raids.

They carried out raids from Scotland to Italy killing, burning and carrying away all they could. As it was hard to make a living in their cold homelands, they raided wealthier lands. However, not all Vikings were raiders. Some travelled to new places to settle. Many became hunters and farmers who never left their homes.

Why beavers build dams

Beavers build their homes in streams but they cannot do so in moving water. So, they first build a dam to make an area of still water. Otherwise the current would wash away the home or lodge they build.

With their huge front teeth, the beavers cut down trees on the banks of the river to build the dam. They plaster the sides with mud and fill out any gaps in the dam with stones and sticks.

Then the lodge is built of sticks behind the dam, with an underwater entrance. The beavers sleep, store food and care for their young in the lodge.

They continuously keep repairing the dam and the lodge to prevent water seeping in. Beavers live in North America and in some parts of Europe and Asia.