3.2 Pressure

• Pressure in solids
• Pressure in liquids
• Factors affecting pressure in solids and in liquids
• Experiments to demonstrate pressure in solids and liquids
• Applications of pressure in day to day life

• describe pressure in solids
• describe pressure in liquids
• determine the factors that affect pressure in solids and in liquids
• carry out experiments to demonstrate pressure in solids and in liquids
• apply knowledge of pressure in day to day life
• appreciate the application of pressure in day to day life

“How does pressure affect our daily lives?”

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1. What pressure is
   40 min · 1 practice tasks · quiz
   Why the same weight can leave a deep mark or a shallow one, depending on the area.
2. Force, area and pressure
   40 min · 1 practice tasks · quiz
   The only two things that change pressure, and which way each one works.
3. Calculating pressure
   40 min · 1 practice tasks · quiz
   The formula, its unit, and how to rearrange it to find a force or an area.
4. More pressure calculations
   40 min · 1 practice tasks · quiz
   Working with square centimetres, several feet at once, and answers that surprise you.
5. Pressure in solids around us
   40 min · 1 practice tasks · quiz
   Four everyday objects designed around area, and how to tell which rule each one uses.
6. Reducing pressure
   40 min · 1 practice tasks · quiz
   Four ways of spreading a force out, and why foundations, skis and straps all work the same way.
7. Increasing pressure
   40 min · 1 practice tasks · quiz
   Concentrating a force onto a small area, and why studs, points and edges all work the same way.
8. Pressure in liquids
   40 min · 1 practice tasks · quiz
   How a liquid presses on its container, and why the pressure is not the same everywhere.
9. Liquid pressure and depth
   40 min · 1 practice tasks · quiz
   An experiment with holes in a jerrycan showing that the deeper the hole, the greater the pressure.
10. Liquid pressure and density
    40 min · 1 practice tasks · quiz
    Why water squirts further than cooking oil from the same depth, and why the shape of the container does not matter.
11. Liquid pressure in all directions
    40 min · 1 practice tasks · quiz
    An experiment with holes around a bottle showing that, at one depth, a liquid presses equally every way.
12. Atmospheric pressure
    40 min · 1 practice tasks · quiz
    The air has weight, it presses on everything, and the pressure is lower up a mountain than at the coast.
13. Straws, syringes and suckers
    40 min · 1 practice tasks · quiz
    How a soda straw, a hospital syringe and a rubber sucker all work because air outside pushes harder than air inside.
14. Dams, water towers and taps
    40 min · 1 practice tasks · quiz
    Why a dam is thickest at the bottom, why the school tank sits on a stand, and why the lower tap runs harder.
15. Hydraulic pressure
    40 min · 1 practice tasks · quiz
    How a garage jack and a car brake use a liquid to turn a small push on a small area into a large force on a large area.
16. Pressure in daily life
    40 min · 1 practice tasks · quiz
    A tour of the applications, from a jembe and a matatu tyre to a borehole pump and a pressure cooker, with the safety that belongs to each.