Why is electricity produced at the bottom of dams?

When you catch a deep-sea fish, why does its eyes pop-out?Why do your ears pop on an airplane or up in the mountains?

Pick 3 pictures and decide what they have to do with pressure

Understand the relationship among

Force Area Pressure

Write detailed explanations about pressure using scientific language.

SKILL

FACT

Literacy

When we talk about pressure in Science we use it as a measure of the ratio of how much push or force there is acting on a given surface area.

Simply put if a girl pushes by the same amount on a desk….

The smaller the contact area the larger the pressure is.

High Pressure Low Pressure

TRY IT!

A

FP

What we have done is work out a qualitative idea for pressure;

“the larger the area is the lower the pressure.”

However we can describe this mathematically;

Force ( N, Newton)

Area (m2 or cm2)Pressure (Pa, Pascal)

2

2

/10

1

10

cmNP

cm

NP

A

FP

A person pushes on a desk with a force of 10N. The contact area of their finger is 1 cm2.

A = Area (m2 or cm2)

Force ( N, Newton)

P = Pressure (Pascal)

10 Pa

2

2

/08.0

125

10

cmNP

cm

NP

A

FP

A person pushes on a desk with a force of 10N. The contact area of their hand is 125 cm2.

A = Area (m2 or cm2)

Force ( N, Newton)

P = Pressure (N/m2 or N/cm2)

10 Pa0.08 Pa

2

2

/08.0

125

10

cmNP

cm

NP

A

FP

We can now see the relationship numerically or quantitatively. As the area increases the pressure decreases;

A = Area (m2 or cm2)

F=Force ( N, Newton)

P = Pressure (Pa, Pascal)

2

2

/10

1

10

cmNP

cm

NP

A

FP

0.08 Pa10 Pa