15. Blow Hot, Blow Cold

TLO: To count the heartbeats. To define stethoscope and write its use. To write the reasons for various effects of blowing on different things. To list and draw few instruments which produce sound on blowing. To write about the different acts of breathing.

Points to Ponder: We blow air from our mouth to warm our cold hands in winters, our breath is warm.We blow on hot potatoes to cool them, as the potatoes are hotter than our own breath.We blow air into some musical instruments like flute, been to produce sound. There are two acts of breathing-Inhalation- it means breathing in. Exhalation- it means breathing out.When inhale our chest goes out and when we exhale our chest goes in.When you blow on a cold mirror in winters, you see drops of water on the mirror, this is because the water vapours in our breath change to water drops after touching the cold mirror. This changes the mirror hazy.Our heart beats faster after we run, skip or exercise.Hot air is light and rises up. Cold air is heavy and comes down.A stethoscope is an instrument used listen to the sound of our heartbeat.We blow on a burning fire to keep it burning so as to increase the supply of oxygen which is essential for burning.A popcorn seller fans the burning coal to increase the oxygen supply.

I. FILL IN THE BLANKS:1. Our nose help us to breathe and smell.2. The process of breathing in is called inhalation and the process of breathing out is called as exhalation.3. Lungs are the organs which help in breathing.4. Stethoscope is an instrument used by doctors to listen the heartbeat of the patient.5. Fire needs oxygen to burn.6. Flute and been are the instruments played by blowing air.7. The average human heart beats around 72 times per minute.8. Hot air is light and rises up. Cold air is heavy and comes down.9. Air blown by us is used for both cool and warm the things.10. Our heart beats faster after we run, skip or exercise.11. A popcorn seller fans the burning coal to increase the oxygen supply

Answer the following:1. Write any 5 situations where you blow air.Ans: we blow air

To put off the candle. To burn fire. To warm our hands in the winter. To blow the balloon. To cool the hot things.

2 .What is Stethoscope?Ans: A stethoscope is an instrument used to listen to the sound of our heartbeats.

3. How does your breath help to warm your cold hands in winters?Ans: The air we breathe out is warm and hence it helps us to warm our cold hands in winter.

4. What happens to your chest when you breathe in and breathe out air?Ans: When we breathe in our chest comes out(expands) and when we breathe out air our chest goes in(Contracts).

5. Name the two acts of breathingAns The two acts of breathing are a) Inhalation- it means breathing in b) Exhalation- It means breathing out6. What happens to your heart beat after you run, skip or exercise?Ans : Our Heart beats faster.

Tell Me Why and How?1 We blow on hot potatoes or hot tea.Ans: We blow on hot potatoes or hot tea to cool them, as the potato or the tea is hotter than our own breath.

2 When we blow on the glass the glass becomes hazy.Ans: When we blow on the glasses the water vapours in our breathe changes to water drops after touching the cold glasses and the glass becomes hazy.

3.Women in the village blow the ember in the chullah.Ans. A women in the Village blows the ember in the chullah so as to increase the supply of air (oxygen) which is essential for burning.

4 We blow our hands in winter.Ans. We blow our hands in winter to make them warm, as the air we blow out is hot.

5. Our heart beats faster after running.Ans: When we run we need more energy (oxygen).so our heart pumps more blood to supply oxygen and thus heart beats faster.

Name and Draw

Name and draw few instruments we blow air into it to produce sound.Ans- Counch Shell, Nadaswaram, Flute, Shahnai, Been, Clarinet, Saxaphone, Trumpet, Mouth organ

Activity:

Perform the following activity and write what happens.a) You blow bee-b) You blow on the spectacles-c) You blow on fire-d) You blow on hot soup-

BEEN

TRUMPET

SAXAPHONE

SHAHNAI

CLARINET

NADASWARAM

FLUTE

GUITAR

CONCH SHELL