Flashcards in Pressure And Density Deck (11):

1

## What is density measured in?

### kg/m³

2

## How to work out pressure

### Pressure = force/area

3

## What is pressure measured in?

###
• N/cm²

• N/m² = Pa (pascal)

4

## What three factors affect the pressure in a fluid?

###
• Depth the pressure is measured at (the greater the depth, the greater the pressure)

• Density of the fluid (the greater the density, the greater the pressure)

• Gravitational field strength (the greater the gravitational field strength, the greater the pressure)

5

## What equation links all the three factors affecting pressure?

###
• pressure = depth x density of fluid x strength of gravity

• p(Pa=N/m²) = h(m) x p(kg/m³) x g(10N/kg)

6

## Three holed can

###
• This can shoes that pressure in a fluid increases with depth.

• Top hole comes out slowest and travels the least distance across, but the bottom hole moves out fastest and travels furthest.

7

## Magdeburg hemispheres

###
• Two metal cups that fit together. If most of the air is removed from inside them using a vacuum pump, it's nearly impossible to pull them apart.

• The pressure of the atmosphere acting on their outside surfaces pushes them tightly together - there is no pressure on the inside because there is no air.

• Once air is let back in, the pressure inside equals the pressure outside and the cups can be easily separated.

8

## Collapsing can

###
• Water is boiled in an empty drinks can.

• When the water has boiled, steam fills the can.

• If the can is then turned upside down in a trough of cold water, the steam condenses and the air pressure inside goes down - causing the can to collapse due to the pressure of the air outside.

9

## How to work out density

### Density = mass/volume

10

## Why does air pressure decrease the higher up you go?

###
• Atmospheric density increases the higher up you go.

• Air is colder higher up, so the molecules are moving less slowly.

11