5.6

5.6

07 October 2011

10:40
5.6 recall and use the relationship for pressure difference:

pressure difference = height × density × g

∆p = h × ρ × g

∆p = pressure of the fluid (N/m2 or Pa)

h = height of the fluid (m)

ρ = density of the fluid (kg/m3)

g = gravitational field strength (N/kg)

5.6 Demo - squirting water column

12 October 2011

07:24

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· The bottom hole squirts water the furthest
· Because the water at the bottom has the greatest pressure
· Because in the formula ∆p = h × ρ × g, ρ is constant, g is constant and h is large
· So ∆p = large

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Objective 5.4

5.4 Starter

07 October 2011

11:46
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5.4 Starter 2 explained

07 October 2011

09:04

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· Your finger pushes on the pin and the pin pushes back on your finger
· N3L tells us that all these two forces are equal in size
· The pin pushes on the wall and the wall pushes back on the pin
· N3L tells us that all these two forces are also equal in size
· If the surface area is large then the force is spread over a large area and the pressure is low
· If the surface area is small then the force is spread over a small area and the pressure is high
· You would like the pressure on your finger to be low and the pressure on the wall to be high
· The other way round is painful!

5.4

07 October 2011

10:37
· 5.4 recall and use the relationship between pressure, force and area:

pressure = force / area

p = F / A

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animation - why a drawing pin works.swf Download this file

5.2

5.2 recall and use the relationship between density, mass and volume:

          density = mass / volume

                  ρ = m / V

Density formula.ppt Download this file

5.3

Density Practical - regular and irregular solids and liquids.ppt Download this file

5.3 describe how to determine density using direct measurements of mass and volume

Untitled

Unit_5_Key_Words.docx Download this file