Pressure
WALT: Explain the concept of pressure and
deduce factors which affects it.
Solve Simple Problems on Pressure in solids.
Keywords: Pressure, Force, Area, Buoyancy,
Compressibility, Barometer, Hydrometer.
Do Now:
Why does hitting a
balloon not pop it
but hitting it with
a pin does?
Success Criteria
I can name what affects pressure.
I can calculate pressure.
I can explain what affects pressure.
I can rearrange the pressure
equation.
I can explain how force and area
affects pressure.
Sooooooooo???????
What is pressure?
Pressure is exerted whenever a force is applied over an area.
1.
2.
If the same force is applied in each picture, which arm exerts the highest pressure
on the board?
Pressure
Two things affect
pressure:
Force
Area
Pressure
Pressure = Force
Area
Increase
Force
Decrease
Area
Look at the equation.
How could you increase the
pressure?
How much pressure do you make?
1.
a.
Draw and describe an
object that is designed to decrease
pressure.
b.
Draw and describe an object
that is designed to increase
pressure.
Explain how each of the objects you
drew either increases or decreases
the pressure.
Explain how force affects pressure.
Snow boards have two features which use
pressure a large flat base and sharp edges.
Explain how these features help the
snowboarder.
1.
a.
Draw and describe an
object that is designed to decrease
Peer Assess:
pressure.
b. You
Drawcan
and describe
an object
describe
how pressure is
that is designed to increase
affected by area.
pressure.
Youhowcan
howyouarea affects
Explain
eachexplain
of the objects
drew
either increases or decreases
pressure.
the pressure.
You can apply your understanding of
pressure toSnow
different
boards haveconcepts.
two features which use
pressure a large flat base and sharp edges.
Next Step: Explain
Calculating
Pressure.
how these features help the
snowboarder.
How can he do this??!
Talk for 1 minute with your partner
and try to come up with an
explanation.
Pressure
Success Criteria
I can name what affects pressure.
I can calculate pressure.
I can explain what affects pressure.
I can rearrange the pressure
equation.
I can explain how force and area
affects pressure.
Pressure
Pressure = Force
Area
Increase
Force
Decrease
Area
Look at the equation.
How could you increase the
pressure?
Guided- Performance on Calculating Pressure:
1. A force of 500 N acts over an area of 10 m2. (Unit: N/m2)
2. A hammer hits a nail with a force of 50 N into some wood. The area of the point of the
nail is 0.02cm2. (Unit: N/cm2)
3. A girl has a weight of 450 N and her feet have a total area of 300 cm2. (Unit: ???????)
Rearranging:
1. A student uses a glue stick with an area of 4 cm2, putting a pressure of 0.5 N/cm2 on
her book. Calculate the force she puts on the glue stick.
2. A box puts a pressure of 50 N/m2 on an area of 0.25 m2. Find the force of the box on
the floor.
3. Calculate the area of a dart which hits the dartboard with a force of 10 N and
pressure of 2000 N/cm2.
ASPIRE: Thinkers:
1. A car of weight 6,400 N has four wheels. Each wheel has an area of 80 cm2 touching the
road. Find the pressure the car puts on the ground.
2. A bridge will break if the material it is made of exceeds a pressure of 500N/m2 . An
elephant stands on the bridge. It has a mass of 500kg and the area of all its feet is 4m.
Does the bridge break?
3. A pressure of 50N/m2 is exerted on a stamp of 1 cm by 1c stamp. What is the force
applied?
Success Criteria
I can name what affects pressure.
I can calculate pressure.
I can explain what affects pressure.
I can rearrange the pressure
equation.
I can explain how force and area
affects pressure.
Answer: True / False
1. Pressure can be measured in N/cm2 or N/m2 or
Pascals.
2. Pressure depends on force only
3. 1 Pascal = 1N/cm2
4. A needle exerts a low pressure when someone is
injected
ASPIRE
Who is more likely to
break the bridge? Be
ready to explain your answer