Loading PDF...
Chapter Analysis
Beginner8 pages • EnglishQuick Summary
The chapter 'Blow Hot, Blow Cold' explores the concepts of air temperature through a story about a woodcutter and Mian Balishtiye. It illustrates how blowing air from the mouth can warm hands and cool hot food, encouraging children to engage with experiments to observe these phenomena. The chapter encourages students to think about the nature of air and its temperature in different contexts.
Key Topics
- •Air temperature
- •Breath temperature
- •Conduction and evaporation
- •Hot and cold air
- •Everyday examples of heat transfer
- •Effect of evaporation on heat
Learning Objectives
- ✓Understand how breath can be used to change temperature
- ✓Describe how air temperature changes in different situations
- ✓Explain the effect of blowing air on hot and cold objects
- ✓Conduct simple experiments to observe temperature changes
- ✓Relate concepts of air and temperature to everyday experiences
Questions in Chapter
Have you warmed your hands in winter by blowing on them when they are cold? How does it feel?
Page 141
Blow hard from your mouth onto your hands. How did you find the air from your mouth as compared to the air around? Was it hotter, or cooler?
Page 141
Now put your hands at some distance from your mouth, and blow again. Does the air from your mouth feel warm? Why?
Page 142
Can you think of any other way in which you use the warmth from your breath?
Page 143
Balishtiye saw that the woodcutter was trying to cool the hot potatoes by blowing on them. What would have happened if he had eaten the potatoes without cooling them?
Page 143
If you were to cool these three hot things – dal, roti, rice – in what ways would you do so?
Page 143
Make whistles of the things given below. Write in a sequence–from the loudest to the softest whistle.
Page 144
For what other things do you blow air from your mouth?
Page 144
Can you name some things which produce melodious or pleasing sounds when we blow into them?
Page 145
We blow to cool hot things as well as to warm them. Give examples of each.
Page 146
Additional Practice Questions
What happens when we blow air onto our hands in winter compared to when we blow on hot tea?
easyAnswer: When we blow on cold hands, the warm air from our breath helps to warm them. Blowing on hot tea helps to cool it down by increasing evaporation.
How does the process of blowing on food change the temperature of the food?
mediumAnswer: Blowing on hot food increases air circulation on the surface, promoting heat loss through convection and evaporation, thereby cooling the food.
Describe an experiment to demonstrate the concept of warm and cool air using a paper snake.
mediumAnswer: Cut a piece of paper into a spiral, hang it near a source of heat like a candle. Observe the snake moves clockwise due to rising warm air, showing warm air rises.
Why does our breath feel warm when we blow on our hands but cool when we blow with force on warm food?
hardAnswer: When blowing on hands, the air retains body heat, feeling warm. Blowing forcefully on warm food increases evaporation, making it feel cooler.
How would you explain the concept of blowing hot and cold with the same breath in simple terms?
easyAnswer: It's all about the context: blowing gently on cold hands transfers warmth, while blowing on hot food increases evaporation, removing heat.