Page 83 - Genius Kidz Prudence Learning Sc-8
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Activity 3 Activity 4
Liquids exert pressure in all the directions. However, Repeat activity 3, with the help of a water bottle and
the pressure inside liquid increase with its depth.” a juice bottle. Make only one hole “A” this time.
Take a bottle of mango juice and prick in it with the What do you observe, in which case is the liquid
help of pin at four points at shown in the figure:- A, flowing out with more pressure? What do you infer
B,C and D. Record your observations as : from this activity? Is the pressure increasing or
decreasing with increase in density??
(a) Is juice coming out of all the holes ? What do you
infer from it?
A
B
C
D Water bottle Juice bottle
(b) At which point the pressure is maximum and at _________________________________________
which it is least? What do you infer from this _________________________________________
observation? _________________________________________
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Everyday examples increases tremendously. That is why camels
So, now you can very well understand why the have broad feet as this reduces the pressure
cutting edges of tools like blades, knives, axes exerted on sand and hence they are able to
are made sharp and why pins and needles have walk easily on sand. For the very same reason
sharp points. However, in some cases it is skis are always made long and flat which
required to reduce the pressure as well. Try increases the area in contact with snow.
walking on sand or snow wearing your So, now can you guess why it hurts to walk over
stilettos. It would be very difficult and almost stones and gravels and why porters while
impossible to walk. This is because all your carrying load place a roll of cloth on their
body weight exerts pressure on a very small head?
surface area due to which the pressure
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