The stars that twinkle in the sky at night are tremendously far away. Even the closest one, called Proxima Centauri suh muh sen eye), is some twenty-five million million miles (forty million...
The circle of stones
> Stonehenge, a large circle of tall stones, was made by ancient people > of England. About four thousand years ago, a group of men gathered together on a broad, green plain in what is now southern...
Measuring speed
The mighty Superman can move faster than a speeding bullet---but how fast is that? A tiny snail creeps along at what is called a "snail's pace"---but how slow is that? There's an easy way to measure...
How far is it?
A map may be millions of times smaller than the real land it pictures. So how can you find out how far it is from one place to another? To find out, you use a "measuring stick" called a scale. Scale...