Activity 8.8:
Aim: To show that air exerts pressure.
Instruction
1. Fill a glass with water until it is full.
2. Cover the mouth of the glass with a card.
3. Hold the card and turn the glass upside down quickly.
4. Remove your hand slowly. Observe if the water flows out (Figure 8.34).
Question
Why doesn’t the water flow out when the hand that presses the card is removed?
Answer:
This is because the atmospheric pressure acting on the card is strong enough to support the weight of the water in the glass.
Aim: To show that air exerts pressure.
Instruction
1. Fill a glass with water until it is full.
2. Cover the mouth of the glass with a card.
3. Hold the card and turn the glass upside down quickly.
4. Remove your hand slowly. Observe if the water flows out (Figure 8.34).
Question
Why doesn’t the water flow out when the hand that presses the card is removed?
Answer:
This is because the atmospheric pressure acting on the card is strong enough to support the weight of the water in the glass.