Advertisements
Advertisements
प्रश्न
Take a sheet of paper. Draw a spiral on it as shown in Figure. Cut out the paper along the line. Suspend the paper as shown in Figure above a lighted candle. Observe what happens. Think of an explanation.

Advertisements
उत्तर
Here is the observation and explanation for the given activity:
Observation: When you cut out the spiral from the paper and suspend it above a lighted candle, the spiral begins to rotate.
Explanation: The heat from the candle flame warms the air around it, causing it to rise. This rising warm air creates a convection current. When the paper spiral is placed above the candle, the rising warm air hits the spiral and causes it to spin. This is because the moving air applies a force to the spiral, making it rotate.
APPEARS IN
संबंधित प्रश्न
No medium is required for transfer of heat by the process of ______.
Select the correct alternative
In the process of convection, heat travel
Give one example of heat transfer by radiation.
The earth receives heat from the sun by ______.
Explain which mode of heat transfer causes sea breezes and land breezes.
Why are heaters fitted near the floor and air conditioners near the ceiling of a room?
Heat is the transfer of energy between two objects at different temperatures.
When a liquid boils, energy is absorbed.
Wrap a thin paper strip tightly around an iron rod. Try to burn the paper with candle while rotating the iron rod continuously. Does it burn? Explain your observation.
Take two similar transparent glass bottles having wide mouths. Put a few crystals of potassium permanganate or pour a few drops of ink in one bottle. Fill this bottle with hot water. Fill the other bottle with cold water. Cover the cold water bottle with a thick piece of paper such as a postcard. Press the postcard firmly with one hand and hold the bottle with the other hand. Invert the bottle and place it on top of the hot water bottle. Hold both the bottles firmly. Ask some other person to pull the postcard. Observe what happens. Explain.
