Explain why are you not able to breath normally when you are in closed and crowded places ?

Why can't you able to compress a wooden block?

Why is a normal eye not able to see clearly the objects placed closer than 25 cm ?

Why don't we hear sounds when our ears are closed?

Explain why hydrogen is not placed with the halogen in the periodic table.

Why do you think some animals eat plastic?

Spring fitted doors close by themselves when released. You want to keep the door open for a long time, say for an hour. If you put a half kg stone in front of the open door, it does not help. The sotne slides with the door and the door gets closed. However, if you sandwitch a 20 g of wood in the small gap between the door and the floor, the door stays open. Explain why a much lighter peice of wood is able to keep the door open while the heavy fails.

When the key is closed, a spark is generated between the ends of the rods. a. Explain the cause of the spark. b. Explain why a spark is also produced when the key is opened. c. Why are no sparks produced when the key is left closed?