Table of Contents
- 1 Why is it necessary to make holes in huge hoardings?
- 2 Why hoarding and banners have holes in them what are the consequences if hoardings are made without holes?
- 3 How can you find out wind direction at a given place?
- 4 Why are holes made?
- 5 Why three are holes on hoardings as well as clothes or plastic banners of advertisements hanged freely?
- 6 Why do banners and advertisement boards get ripped and blown off during cyclone?
- 7 What causes wind movement?
- 8 Why there are holes in banners and hoardings Class 7?
Why is it necessary to make holes in huge hoardings?
Why are these necessary? Answer: The holes in the hoardings are necessary to reduce the air pressure so that the air instead of applying force on the hoarding passes away from the holes.
Answer : Holes are made in hanging banners and hoardings so that air can pass through them easily and reduce the air pressure. If banners and hoardings do not have holes, the pressure exerted by wind may tear them off, loosen them or make them fall.
Why hoardings or banners are not damaging by high speed wind?
SOLUTION: Holes are made in hanging banners and hoardings so that air can pass through them easily and to reduce the air pressure. If banners and hoardings do not have holes, pressure exerted by wind may tear them off, loosen them or make them fall.
How can you find out wind direction at a given place?
Two methods to find out wind direction at a given place are (i) An instrument called anemometer can be used to find the direction and speed of the wind. (ii) Hold a strip of paper outside. The direction in which the paper is blowing, is the direction in which the wind blows.
Why are holes made?
Answer: Holes are made in hanging banners and hoardings to allow air to pass through them as a result of which there will be less pressure of air on the banners or hoardings. Unless it is done, these may be uprooted or distorted due to the pressure of the air.
What is air pressure state two experiences that made you think that air exerts pressure?
The experiences that show air exerts pressure are: When we blow a balloon, it becomes tight. If we try to fill more air then the balloon will burst after an extent. This happens because the air exerts pressure.
Explanation: It is due to this pressure that the leaves of trees, banners, or flags flutter when the wind is blowing. The pressure of air inside the can decreases than the pressure exerted by the air from outside the can. As a result the can gets compressed.
What causes change in the direction of winds?
A major factor that determines wind direction is air pressure. Wind travels from areas of high pressure to areas of low pressure. Additionally, heat and pressure cause the wind to shift direction. Additional factors that affect wind direction are the Coriolis Effect and Topography.
What causes wind movement?
Wind is the movement of air caused by the uneven heating of the Earth by the sun. Warm equatorial air rises higher into the atmosphere and migrates toward the poles. This is a low-pressure system. At the same time, cooler, denser air moves over Earth’s surface toward the Equator to replace the heated air.
Why are holes made in the soil?
Wild animal activities create holes in the garden. Birds, squirrels and other animals dig in soil looking for insects or food they previously buried. Animals also burrow into soil and nest underground. Areas near tree snags and roots that have holes could be the burrows of rats or chipmunks.