Do now! Can you complete any unfinished calculations from last lesson??

Do now!

Can you complete any

unfinished calculations from

last lesson??

Last lesson

Calculating density

Density

Remember that density is the mass of one cubic centimetre (or sometime cubic metre) of a substance.

So for example, gold has a density of 19.3 g/cm3. His means one cubic centimetre (cm3) of gold has a mass of 19.3 grams.

Density = mass

volume

Or using the formula triangle;

m

D x V

g/cm3

g

cm3

The formula!

Density of regular shapes

volume = length x width x height

density = mass/volume

mass using a scale

lengthwidth

height

Density of liquids

Mass of liquid and cylinder

Mass of cylinder

Mass of liquid

Density = mass/volume

Volume

Density of irregular shapes (1)

Difference in level gives the volume of the shape

mass

Density = mass/volume

Density of irregular shapes (2)

Displacement can

volume of object

mass

Density = mass/volume

I’m worried!

I’m worried!

Some more density questions. Homework due for 8th September

(Tuesday)

This lesson

• Recall and use the relationship between pressure, force and area

Oh no!

http://wm-od.cdn.turner.com/cnn/big/bestoftv/2007/04/06/roberts.the.shot.cnn.ws.wmv

Spread the force over a greater area

Camels

Snow shoes

Tom

Caterpillar tracks

House foundations

Sharp?

I had a dream

Death?

Drawing pins

Pressure

Pressure = Force

AreaN/m2 or Pa

N

m2

Pressure

Pressure = Force

AreaN/m2 or Pa

N

m2

F

AP x

Can you copy this please?

An example

A woman of weight 600N has a shoe area of 150 cm2 and a man of weight 750 N has a shoe area of 360 cm2. What is the pressure beneath their feet?

An example

A woman of weight 600N has a shoe area of 150 cm2 and a man of weight 750 N has a shoe area of 360 cm2. What is the pressure beneath their feet?

Angelina pressure = force/area = 600/150 = 4 N/cm2

Brad pressure = force/area = 750/360 = 2.1 N/cm2

Let’s try some questions!

Page 63, questions 1 to 4.

Can you then write (and answer) 3 questions of

your own?