Got a DVD series suitable for children aged 3-12,十万个为什么？, from aPee. Will try to compile as many questions as possible not a million. And hopefully these could help you in replying your young ones.
Stay tuned for more ;)
1) Why thunder comes after lightning?
- Light moves faster than sound.
2) Why do people yawn?
- Human need to inhale oxygen and exhale carbon dioxide to survive. When we are tired, more carbon dioxide is produced. If it doesn't get expelled fast enough, it will cause harm to the body.
Yawning is like deep breathing, it helps us inhale more oxygen and get rid of the harmful carbon dioxide. That's why yawning, in a way, protects our health.
3) Why do people have dreams?
- Our brain is made up of lots of nerve cells. These cells are very important as they deal with our sight, hearing, thinking, movement and so on. They work very hard during the day. At night, when we sleep, our brain will start to relax but not all the brain cells will stop working at the same time. It is those cells that are still active that cause us have dreams.
What we see or hear or expecting in the day may appear in our dreams.
4) Why do we have earthquakes?
- Most earthquakes are caused by the movement of the earth's crust. When this happens, the rocks on the earth's surface start to move. As the pressure becomes greater, some of the rocks will crack or collapse. This is known as an earthquake.
The force it creates is very similar to a volcano which is erupting. The collapse of the layer of line just under the ground will also cause tremors. The tremors will then spread from the center of the quake to the area around it. The tremors is greater as it is closer to the center and become weaker as it moves further away from the center.
Actually there are slight tremors happen every 2 minutes or so, but we normally don't feel it. As for strong earthquakes, they happen about 20 times every year.
No comments:
Post a Comment