PASCAL’S LAW

UNDERSTANDING MATTER & ENERGY FLUIDS

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UNDERSTANDING MATTER & ENERGY FLUIDS

3.6  explain in qualitative terms the relationship between pressure, volume, and temperature when a liquid (e.g., water) or a gas (e.g., air) is compressed or heated

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CURRICULUM

PRESSURE

• some devices are designed to increase pressure
• e.g. the force you apply to the head of a thumbtack is transferred to the tiny area of the point

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• some devices are designed to decrease pressure
• e.g. People wear snowshoes to distribute their weight over a larger area

pressure is the force applied to unit of surface area

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ATMOSPHERIC PRESSURE

is the force the atmosphere exerts on a unit of surface area

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• is the force the atmosphere exerts on a unit of surface area

ATMOSPHERIC PRESSURE

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Atmospheric pressure is highest at sea level because this is when the column of air above you is largest

Atmospheric pressure decreases as you move upwards because the column of air above you become smaller

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Atmospheric pressure is highest at sea level because this is when the column of air above you is largest

Atmospheric pressure decreases as you move upwards because the column of air above you become smaller

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PASCAL’S�LAW

a force applied to a fluid is distributed equally in all directions

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PASCAL’S�LAW

a force applied to a fluid is distributed equally in all directions

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Pressure =

____________

Force

Area

Measured in: Newtons (N)

Measured in: �Square Metres (m²)

Measured in: �Pascals (Pa)

1 Pa = 1 N/m²

PASCAL’S�LAW

a force applied to a fluid is distributed equally in all directions

​

P =

___

F

A

What if we need to solve for FORCE?

P =

___

F

A

x A

x A

/

/

P x A = F

F = PA

p

PRESSURE

a

AREA

f

FORCE

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p

PRESSURE

a

AREA

f

FORCE

PRESSURE = Force ÷ Area

​

FORCE = Pressure x Area

​

AREA = Force ÷ Pressure

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p

PRESSURE

a

AREA

f

FORCE

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PASCAL’S�LAW

we can decrease pressure by increasing the area a force is spread over

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a force applied to a fluid is distributed equally in all directions

​

PASCAL’S�LAW

Assume you exert a force of 600 N. Calculate the pressure you exert when:

• wearing 0.02 m² shoes

​

​

• wearing 0.25 m² snow shoes

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a force applied to a fluid is distributed equally in all directions

​

= 30 000 Pa

= 2 400 Pa

PASCAL’S�LAW

we can increase force by increasing the area the pressure is applied over

​

a force applied to a fluid is distributed equally in all directions

​

PASCAL’S�LAW

You exert a 1 N force on a 1 m² plunger, resulting in 1 Pa of pressure.

• Assume it is connected to another plunger that is 5 m² and calculate the force on the second plunger.

​

​

• this is why we say that hydraulics are ‘force multipliers

a force applied to a fluid is distributed equally in all directions

​

= 2 400 Pa

F = PA

F = 1Pa x 5m²

F = 5 N

We push Piston A:

• with less force
• farther

And Piston B rises:

• with more force
• not as far

hydraulic systems are considered �FORCE MULTIPLIERS

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hydraulic systems are considered �FORCE MULTIPLIERS

• pushing on a small plunger at one end of the system will put pressure on the fluid

​

• this pressure will be distributed equally throughout the fluid and will raise another, larger plunger the same amount

​

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hydraulic systems are considered �FORCE MULTIPLIERS

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• Pressure
• Atmospheric Pressure
• Force Multipliers

ADD IT TO THE

W

WORD

W

WALL