Pressure

Ks3 Science

Aims

Aim;

 Understand the relationship between;    Force Area Pressure FACT AIM  Write detailed explanations about pressure using scientific language. SKILL AIM Odd one out

Which is the odd one out and why?

Simple definition

Pressure;

 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. TRY IT!

High Pressure Low Pressure

Literacy

Pressure;

 Use the writing frames in the next slides to help explain what is happening in the two pictures underneath.

 Pick from the options and construct a paragraph on your sheet.

Footballers boot Camels foot

Describe Answers

Create your sentences;

The studs sink because Answers they are small,  they are sharp, the person is heavy,  they have a small surface area,  the pressure is low, the pressure is high,  the persons weight is spread out, the persons weight is concentrated 

Create your sentences;

The camel has large feet because it is heavy,  it lives on sand,  Answers its body weight must be concentrated, sand is soft,  its body weight must be spread out,  this stops it sinking,  this creates lower the pressure,  this increases the pressure.

Pressure;

 Watch the two video clips about pressure and do the same task.

 This time use your own explanations using your previous examples for reference.

Describe

Nettle Stings Tank v Ballerina

Odd one out

Which is the odd one out and why?

Aims

Aim;

 Understand the relationship between;    Force Area Pressure FACT AIM  Write detailed explanations about pressure using scientific language.  SKILL AIM Odd one out

Sharing/ Division?

 If I have an apple and share it between 2 people or 4 people I can write mathematically as; 1  2  0 .

5  1 2  So each person either gets a half an apple or a quarter of an apple. The more people I share it with the less apple the get each.

1  4  0 .

25  1 4 Simple definition

Pressure;

 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;

P



F A

Pressure (N/m 2 or N/cm 2 ) Force ( N, Newton) Area (m 2 or cm 2 )

Pressure Examples;

 A person pushes on a desk with a force The contact area of their finger is 1 cm 2 .

of 10N.

P



F A P

 10

N

1

cm

2

P

 10

N

/

cm

2 A = Area (m 2 or cm 2 ) Force ( N, Newton) P = Pressure (N/m 2 or N/cm 2 )

Pressure Examples;

 A person pushes on a desk with a force of 10N. The contact area of their hand is 125 cm 2 .

P



F A P

 10

N

125

cm

2

P

 0 .

08

N

/

cm

2 A = Area (m 2 or cm 2 ) Force ( N, Newton) P = Pressure (N/m 2 or N/cm 2 )

Pressure Comparison;

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

P



F A P P

 10

N

125

cm

2  0 .

08

N

/

cm

2

P



F A P P

 10

N

1

cm

2  10

N

/

cm

2 A = Area (m 2 or cm 2 ) Force ( N, Newton) P = Pressure (N/m 2 or N/cm 2 )

Aim;

 Understand the relationship between;    Force Area Pressure FACT AIM   Write detailed explanations about pressure using scientific language.  SKILL AIM Odd one out