What enables ducks to swim on water? The duck’s feathers have tiny projections called barbules which hook together and trap air between the feathers. The duck has air sacs connected to the lungs which help to hold air inside its body. The air between the...
How big are asteroids? Asteroids are big lumps of rock or ice. Most of these are only a few tens of kilometres across. The biggest asteroid is Ceres. It is about 1,000 km across. Ceres was discovered in 1801. Others like Pallas and Vesta are...
Which babies are carried piggy-back by their mothers? Like the kangaroo baby the joey, the koala bear too is carried in its mother’s pouch for the first six months after its birth. But after that the koala bear cub climbs on the mother’s back and...
What is a chiton? A chiton was a garment worn by ancient Greeks. It was a large rectangular piece of cloth fastened at the shoulders. It usually came in colours like saffron yellow, purple, red and violet. The chiton was worn by everyone, men and...
Who invented the wheel? A It is not known when exactly the wheel was invented. The potter’s wheel was in use in Mesopotamia around 6,000 years ago. By 3,200 BC, the Sumerians had begun to use simple carts. These gave way to wheeled chariots pulled...
Which babies are born with a packed lunch? Before it is born, a baby fish draws nourishment from the yolk in its egg. This helps it to grow. After it comes out of the egg, too, some of the yolk remains and it carries this...
Do animals mate for life? Marital fidelity is not very common in the animal world. An exception is the jackdaw, a small bird resembling a crow. These birds choose their mates early—at the age of one! They have chicks when they are two years old....
How is a geyser formed? Rain and melted snow pass via narrow channels or tubes which descend from an opening on the earth’s surface towards red-hot magma below. Magma makes the rock hot which heats the water at the bottom of the tubes. The water...
Why is the planet Mercury so hot? Mercury spins very slowly on its axis when it travels around the sun. This means that a point on its surface is exposed to the sun for almost six months (as on Earth) at a time. This makes...
Why do hippos wallow in the mud? Hippos are found near swamps and rivers. They like to spend time in the water and even remain immersed underwater for hours at a time. Wallowing in the mud is a favourite activity of hippos. This cools the...
