Why is Uranus called the topsy-turvy planet? Planets spin around their axis while orbiting the sun. In other planets the axis is almost upright but in Uranus, the axis is at right angles to normal which makes it seem as if Uranus is lying on...
Why do people yawn? It is not just people who yawn. Even cats and dogs do. Sometimes we yawn when we are feeling sleepy or bored. It is believed that yawning makes us more alert. During yawning, the facial muscles and neck muscles are stretched....
What are yin and yang? According to Chinese beliefs, everything in nature exists in a state of harmony. The famous Chinese thinker, Confucius, used the symbols, yin and yang, to depict this. Yin is dark and yang is light. Both interlock with each other and...
Who were the Spartans? Sparta was a city state in southern Greece. It was a great military power. Spartan men had to join the army and boys had to leave home when they were seven, to get trained as soldiers. The women too had to...
Why is it difficult to breathe on high mountains? High up in the mountains, the air is thin as it has fewer molecules of gases, including oxygen which we need to live. When there is less oxygen in the air, we find it hard to...
What is the difference between warm-blooded and cold-blooded animals? Warm-blooded animals generate their own heat and retain it with the help of feathers, fur and fat. Their body temperature is regulated by the brain. Cold-blooded animals cannot regulate their body temperature from within and their...
What is colour blindness? Eyes have two types of light-sensitive cells rods and cones. Rods help us see shades of grey. Cones help us see colours. People with colour blindness have defective cones. It also happens that information gathered by cones may not be conveyed...
Who was Nebuchadnezzar? Nebuchadnezzar was the ruler of Babylon. He made Babylon one of the richest cities in the world. It was he who created the famous ‘Hanging gardens’ which was one of the seven wonders of the world. For the gardens he brought plants...
What is the difference between a meteor and a meteorite? Meteoroids are small lumps of rock or ice. They become visible when they collide with the earth’s atmosphere. Then they are seen as streaks of light or meteors, also called ‘shooting stars.’ Meteorites are just...
How is a rainbow formed? Rainbows are usually seen soon after a summer rain. It happens when sunlight shines through raindrops which are still present in the air. Light, which appears to be white in colour, is actually a combination of colours like violet, indigo,...
