Airflow

Q.

What is the least count of the ‘Celsius thermometer’?

Q. If you blow air from your mouth onto your hand, then the air feels __________ on your hand.

1. cold
2. warm
3. wet
4. itchy

Q. Explain why bathroom mirror becomes hazy after a hot shower.

Q. Thermometer is used to measure:

1. temperature of the body
2. amount of water in the body
3. warmth of air coming out of mouth
4. heart rate of the body

Q. Which direction does the air flows when paper snake spins in anti-clockwise direction?

1. Left to right
2. Right to left
3. Downwards
4. Upwards

Q. For what other things do you blow air from your mouth? (2 marks)

Q. Hot air moves upwards.

1. True
2. False

Q. Paper snake spins in clockwise direction when hung near a burning candle.

1. False
2. True

Q. When a candle is kept under a spiral that is in the form of a snake, what will we observe?

1. Spiral rotates in anti-clockwise direction
2. Spiral bounces up and down
3. Spiral does not show any change
4. Spiral rotates in clockwise direction

Q. Which direction is the air flowing when paper snake spins in clockwise direction?

1. Left to right
2. Right to left
3. Upwards
4. Downwards

Q.

A ___ igloo traps inside the heat so that the warmth inside the structure does not escape in cold regions.

Q. Rapunzel and Flynn were looking at the night sky. They saw the sky was filled with beautiful sky lanterns. This made Flynn wonder how these sky lanterns were floating in the sky. To this Rapunzel answered correctly and cleared his doubt. Choose the correct answer from the following options.

1. The lanterns are filled with cold air and cold air always rises up.
2. The lanterns are filled with hot air and hot air always rises up.
3. The candle flame below the lantern makes the lantern bright.
4. The lanterns are very light weight and gravitational force doesn’t work.

Q. Which of the following method can not be used for cooling hot food items?

Q. Sonu was feeling very cold. He kept blowing on to his hands. Why did he do that ?

1. Sonu's breath was hotter than his skin (particularly on a cold day). By blowing, he transfer energy from inside his body to hands by convection.
2. Sonu's breath was cooler than his skin . By blowing out this cooler air out, Sonu felt warmer inside
3. Sonu's exhales out cool air and breathes in the air in the atmosphere which is relatively warmer and thus feels warm.
4. None of the above

Q. Why liquid ammonia is used in refrigerators?

Q. Hot air always rises up.

1. False
2. True

Q. In which direction is the air flowing when the paper snake spins clockwise as viewed from the top?

1. Right to left
2. Upward
3. Downward
4. Left to right
   

Q. Mini tried to cool her tea by blowing on it. Which of the following do you think will be hotter ?

1. Mini's tea
2. The air she blew from her mouth
3. The atmospheric air
4. None of these

Q. If you blow air from your mouth onto your hand, then the air feels __________ on your hand.

1. cold
2. warm
3. wet
4. itchy

Q. Identify the instance when blowing air from the mouth helps to cool things up ?

1. Blowing over hands on a cold day
2. Blowing over leaves fallen on ground
3. Blowing over sharpener fillings
4. Blowing over coffee

Q. Identify the instance when blowing air from the mouth helps to warm things up ?

1. Blowing over tea
2. Blowing over hands after rubbing them on a snowy day
3. Blowing over rubber particles after using an eraser
4. Blowing over spectacles

Q. Which among the following instruments is not played by blowing air into it?

1. Flute
2. Guitar
3. Shehnai
4. Mouth Organ

Q. If you take ice cold water in a glass tumbler, you will observe some water droplets on its outer surface. What can we infer from this?

1. Air occupies space.
2. Air contains nitrogen gas.
3. Air contains water vapour.
4. Air contains oxygen gas.

Q. When water boils, it gets converted into its gaseous form, which is steam.

1. True
2. False

Q. The hot air we breathe out contains water vapours which turn into tiny droplets of water when it comes in contact with the colder glass of spectacles.

1. True
2. False

Q. Now put your hands at some distance from your mouth and blow again. Does the air from your mouth feel warm? Why?

Q.

why a house made up of ice does not melt in the tundra region and keeps the eskimos warm?

Q. How do you cool food when it is too hot to consume?

1. Add sugar to it
2. Put it in a microwave
3. Put in refrigerator
4. Keep it in a broad container and blow air over it