Year 9

Edexcel Science
iGCSE Physics

D. Pressure and
Density
2019-2020

Name:________________
Physics Teacher:______________

House CG
 Specification Checklist

5.01 use the following units: degree Celsius (°C), Kelvin (K), joule (J), kilogram (kg),
kilogram/metre3 (kg/m3 ), metre (m), metre2 (m2 ), metre3 (m3 ), metre/second (m/s),
metre/second2 (m/s2), newton (N) and pascal (Pa)

5.03 know and use the relationship between density, mass and volume:
mass
density =
volume

m
ρ=
V

5.04 practical: investigate density using direct measurements of mass and volume

5.05 know and use the relationship between pressure, force and area:
Force
Pressure=
Area

F
P=
A
5.07 know and use the relationship for pressure difference:

pressure difference = height × density × gravitational field strength

P=h× ρ × g

Pressure and Density – Science (Physics) 2

Key Words

Key Word Image Definition

Accuracy How close the average experimental value is to the actual

value.

Balance A piece of equipment for measuring the Weight or Mass of an

object.

Density The amount of mass inside an object of set volume.

Measured in [kg/m3] or [g/cm3].

Displacement An object that is placed in water will make the water level
rise by the same amount as its own volume.

Measuring A tall cylinder with a measuring scale on the side.

Cylinder

Meniscus The curved upper surface of a column of liquid. You should

always measure your reading from the bottom of the
meniscus.

Newton The Unit of force. [N].

Parallax Error When using a measuring cylinder, you must have your eye in
line with the water level. Or you could make a mistake in your
reading.

Pascal The unit for pressure. One Newton per metre squared [N/m2].

Precision The decimal places that your answer can be measured to. You
can improve precision by using a smaller scale on your
equipment.

Pressure The amount of force exerted on a set area. Measured in

Pascal’s [Pa], [N/m2] or [N/cm2].

Pressure and Density – Science (Physics) 3

1: Density of a Regular Solid
Knowledge and Understanding Quiz
Use the knowledge you have gained in previous topics to answer the following questions:

1. What is the weight of an object that has a mass 600g?

……………… (2)

2. What is elastic behaviour?

…………………………………………………………………………………………
………………………………………………………………………………………… (1)

3. What is a vector quantity?

…………………………………………………………………………………………
………………………………………………………………………………………… (2)
4. What is the definition of frequency?
…………………………………………………………………………………………
………………………………………………………………………………………… (1)
5. If a wave is travelling at 5m/s and has a frequency of 200kHz, what is its
wavelength?

……………… (3)
6. In what direction does friction act?
…………………………………………………………………………………………
………………………………………………………………………………………… (1)
7. Give the order of the EM spectrum from highest to lowest frequency.

(2)

Score [ /12]

Pressure and Density – Science (Physics) 4

Learning Outcomes:

1. Use and rearrange the equation

m
ρ= to calculate the density of a solid.
V
2. Carry out an investigation to find the density of a regular solid.
3. Use Vernier callipers and explain why they can produce better results when
measuring length than a ruler.
Density

Key Ideas
1. Density, mass and volume are linked in the equation:

mass
density =
volume
2. Density is denoted with the greek symbol ‘roe’ [ ρ ¿
3. There are two set of units that are commonly used with the above equation:
a. Density in [g/cm3], mass in [g] and volume in [cm3].
b. Density in [kg/m3], mass in [kg] and volume in [m3].
Worked Examples
1. What is the density of an object with a mass of 650kg, and a volume of 24m3?

2. A block of wood has a density of 0.6g/cm3. What would be the volume of a piece of
wood which has a mass of 800g?

Pressure and Density – Science (Physics) 5

Worksheet – Calculating Density
Complete the questions below using the equation you have just learnt. You must show all
of your working [equation, substitution, solution and units]
1. What is the density of a cube of mass 850g which takes up a volume of 60cm3?

…………………..

2. What is the density of a cylinder of mass 6kg which takes up a volume of 0.52m3?

…………………..

3. What is the density of a metal cuboid of mass 2.5kg which takes up a volume of
0.2m3?

…………………..

4. An object of density 4000 kg/m3 has a mass of 2000 kg. What is its volume?

…………………..

5. A brick of density 2.8 g/cm3 has a mass of 1200g. What is its volume?

…………………..

6. What is the mass of 4 m3 of cement, of density 3000 kg/m3?

…………………..

7. What is the mass of 6 cm3 of ice, of density 0.9 g/cm3?

…………………..

Pressure and Density – Science (Physics) 6

 8. A barometer is to be filled with 0.001 m3 of mercury. It is more accurate to weigh the
mercury, rather than to measure its volume. What is the mass of this volume of
mercury? (Density of mercury = 13 600 kg/m3)

…………………..

9. A steel cube has sides of length 10 cm. What is its mass? (Density of steel = 7.7
g/cm3)

…………………..

10. A science lab has dimensions of dimensions 8 m x 5 m x 3 m. What is the mass of

the air in the lab? (Density of air = 1.3 kg/m3)

…………………..

11. A full bucket contains 20 000g of water. What is the volume of the bucket? (Density
of water = 1000 kg/m3)

…………………..

12. Find the mass of a sphere of wood of radius 0.5m. You will need to use the equation
3
4π r
for calculating the volume of a sphere which is V = . The density of the wood is
3
350 kg/m3.

…………………..
13. How much does 1000 cm of water weigh? (Density of water = 1 g/cm3)
3

…………………..

14. An apple is found to weigh 1 N. If its volume is 125 cm3, what is the density of the
apple?

Pressure and Density – Science (Physics) 7

 ………………….
D1: Measuring the Density of a Regular Solid. Health and Safety Check!

In this investigation you are going to be carrying out Vernier Callipers have
an investigation to find the density of a variety of sharp edges. Be
regular solids. sensible when using
them.
A regular solid, is one where we know how to calculate
it’s volume.

In the space below, note how to find the volume of the following 3D shapes.

Triangular
Cylinder

Sphere
Cuboid
Cube/

Prism
Method

1. Find the mass of your object using a balance

2. Use the Vernier callipers to measure any required dimensions for your object. We
use these to improve the accuracy of our readings (NOT of our result).
*Tip: If you need to measure the radius, first find the diameter then half it*
3. Calculate the volume of your object using the correct formula [above].
4. Calculate the density of your object using the equation:
mass
density =
Volume
5. Repeat steps 1-4 for a new object.
*Try to do a variety of different shapes and materials of objects*

Pressure and Density – Science (Physics) 8

Results

Object
Description Dimensions Volume Density
Mass [g]
[shape, [cm] [cm3] [g/cm3]
material]

Which material was the most dense?

……………………………………………………………………………………………………………

Did the shape of the material have any impact on it’s density? [Hint: find someone else who
found the density of an object with the same material but a different shape]
……………………………………………………………………………………………………………

Pressure and Density – Science (Physics) 9

……………………………………………………………………………………………………………

Worksheet – Precision and Accuracy

A good analogy for understanding accuracy and precision is to imagine a basketball player
shooting baskets. If the player shoots with accuracy, his aim will always take the ball close
to or into the basket. If the player shoots with precision, his aim will always take the ball to
the same location which may or may not be close to the basket. A good player will be both
accurate and precise by shooting the ball the same way each time and each time making it
in the basket.
Section A: Using the above analogy can you describe each of the terms in your own words:
Precision:
……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

Accuracy:
……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

A B C D

Section B: Above there are 3 targets A, B, C and D. Use these to answer the following
questions:
1. Which of the target(s) shows precise shooting? ………………

2. Which of the target(s) shows accurate shooting? ………………

3. Do any of the targets show neither precise nor accurate shooting? ………………
Section C: Illustrate the indicated accuracy and precision on the targets below:

Accurate but not Precise but not

Precise (Physics)
Pressure and Density – Science Accurate 10
Pressure and Density – Science (Physics) 11
2: Density of an Irregular Solid
Knowledge and Understanding Quiz
Use the knowledge you have gained in previous topics and last lesson to answer the
following questions.

1. What is the value of g on a planet when you have a weight of 2kN when your mass is
62kg?

……………… (3)

2. On the image below add:

a. a cross to represent the position of the centre of gravity (1)
b. an arrow to represent the objects weight. (2)

3. What is the definition of a time period?

…………………………………………………………………………………………
………………………………………………………………………………………… (1)
3
4. What is the density of a metal block with a mass of 60kg and a volume of 2.5m ?

……………… (3)
5. Which three parts of the EM spectrum are used for communication?
…………………………………………………………………………………………
………………………………………………………………………………………… (3)

Score [ /13]

Pressure and Density – Science (Physics) 12

Learning Outcomes:

1. Describe how to use the displacement of water to find the volume of an

irregular solid.
2. Carry out an investigation to find the density of an irregular solid.
3. Describe parallax error and explain what experimental practices can be
used to avoid it.

Displacement and Archimedes

Key Ideas

1. We can measure the volume of an irregular object using displacement

2. If we submerge and object in water, the volume of the object is equal to how much
the volume of the water increases by.
3. This was first discovered by Greek scientist Archimedes.
4. 1ml of water = 1cm3 of water
5. A great video to watch on Archimedes can be found at this link
https://www.youtube.com/watch?v=ijj58xD5fDI

Pressure and Density – Science (Physics) 13

 Health and Safety Check!
D2: Measuring the Density of an Irregular Solid.
You are working with
In this investigation you are going to be carrying out electronic balances and
water. Ensure hands and
an investigation to find the density of a variety of
objects are dry before
irregular solids.
using electronics.
How do we calculate the volume of an irregular solid?
……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

We are going to be reading volume from a measuring cylinder. We do this by measuring

from the meniscus to avoid parallax error.

Identify the meniscus in the diagrams below and write down the volume of the liquid.

Volume: Volume: Volume:

Method

1. Find the mass of your object using a balance

*Tip: This should be done first to ensure the object is not wet*
2. Fill you measuring cylinder with a sensible amount of water and read off the volume
from the meniscus.
3. Submerge your object fully in the water then read off the volume from the meniscus.
4. Calculate the volume from the water displacement.
5. Calculate the density of your object using the equation:
mass
density =
Volume
6. Repeat steps 1-5 for a new object.
*Try to do a variety of different shapes and materials of objects*

Pressure and Density – Science (Physics) 14

Results

Object
Volume: Volume:
Description Volume: Density
Mass [g] water water +
[shape, object [cm3] [g/cm3]
[cm3] object [cm3]
material]

Why did we measure the mass of the object while it was dry?

……………………………………………………………………………………………………………

Did the shape of the material have any impact on it’s density? [Hint: find someone else who
found the density of an object with the same material but a different shape]
……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

Pressure and Density – Science (Physics) 15

Parallax error

Key Ideas

1. A parallax error is the perceived shift in an object's position as it is viewed from

different angles.
2. This can result in an inaccurate reading of the scale
3. This most commonly happens when using a measuring cylinder or thermometer.
4. To reduce parallax error we should make sure we make all reading at eye level, in
line with the scale we are using.
5. A great video to watch on this can be found here (it has a dinosaur in it!):
https://www.youtube.com/watch?v=C-vSdlJ-Fa8

Pressure and Density – Science (Physics) 16

3: Density of a Liquid
Knowledge and Understanding Quiz
Use the knowledge you have gained in previous topics and lessons to answer the following
questions.

1. What is the density of a cube of mass 550g and with sides of length 3cm?

……………… (4)

2. What is the definition of a longitudinal wave?

…………………………………………………………………………………………
………………………………………………………………………………………… (2)

3. A metal block has a density of 2.4g/cm3. If it has a mass of 1kg, what is it’s volume?

……………… (4)
4. Give 2 dangers of UV light?
…………………………………………………………………………………………
………………………………………………………………………………………… (2)

5. Give an example of a scalar quantity.

………………………………………………………………………………………… (1)

Score [ /12]

Pressure and Density – Science (Physics) 17

Learning Outcomes:

1. Describe how to find the volume of a liquid using a balance

2. Carry out an investigation to find the density of a liquid
3. Describe what a zero error is and how this can lead to a systematic error in
your results.

Health and Safety Check!

D3: Measuring the Density of a Liquid.
You are working with
In this investigation you are going to be carrying out electronic balances and
water. Ensure hands are
an investigation to find the density of a variety of
dry before using electronics.
liquids.

How do we find the mass of a liquid using a balance?

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

How will we avoid a zero error in our readings?

……………………………………………………………………………………………………………

Method

1. Find the mass of your empty measuring cylinder using a balance

*Tip: This should be done first to ensure the object is not wet*
2. Fill you measuring cylinder with a sensible amount of water and read off the volume
from the meniscus.
3. Find the mass of your filled measuring cylinder using a balance.
*Safety: You are using electronics with water, make sure your hands are dry*
4. Calculate the mass of your liquid by subtracting the mass of your cylinder from your
result in step 3.
5. Calculate the density of your object using the equation:
mass
density =
Volume
6. Repeat steps 1-5 for a new liquid

Pressure and Density – Science (Physics) 18

Results

Mass: Mass: Mass:

Volume Density
Liquid empty filled Liquid
[cm3] [g/cm3]
cylinder [g] cylinder [g] [g]

What was the hardest part about this investigation?

……………………………………………………………………………………………………………
……………………………………………………………………………………………………………

How did you avoid parallax error during the investigation?

……………………………………………………………………………………………………………

……………………………………………………………………………………………………………

The density of water is 1g/cm3. Calculate the percentage difference in your answer you got
from the investigation:

Actual Value−Measured Value

Percentage error = × 100
Actual Value

…………………….

Pressure and Density – Science (Physics) 19

Zero Error

Key Ideas

1. Zero error occurs when your measuring device (e.g. balance, digital callipers, and
scales) is registering a reading when there should be none.
2. This often happens when you forget to zero your device before use.
3. Consistent occurrence of zero error during an experiment can lead to a systematic
error.
4. It can be hard to tell if you have encountered a zero error from your results as they
may still be precise (close together).
5. A great video to watch on this can be found here:
https://www.youtube.com/watch?v=wmlBEjiI4LQ

Pressure and Density – Science (Physics) 20

Worksheet – Measurement and Density

1.

2.

Pressure and Density – Science (Physics) 21

3.

Pressure and Density – Science (Physics) 22

4.

Pressure and Density – Science (Physics) 23

5.

Score [ /30]

Pressure and Density – Science (Physics) 24

4: Pressure under a solid
Knowledge and Understanding Quiz
Use the knowledge you have gained in previous topics to answer the following questions:

1. An object has a mass of 650kg and a density of 2350 kg/cm3. What volume does this
object take up?

……………… (3)

2. Give an example of a scalar quantity

………………………………………………………………………………………… (1)

3. Which two parts of the EM spectrum are used for cooking?

…………………………………………………………………………………………
………………………………………………………………………………………… (2)

4. Which two parts of the EM spectrum can we sense with our bodies?
…………………………………………………………………………………………
………………………………………………………………………………………… (2)

5. Sketch a force-extension graph below for an object that obeys Hooke’s Law

(3)
6. What is the frequency of a wave which travels at 16m/s and has a wavelength of
12cm?

(3)

Score [ /14]

Pressure and Density – Science (Physics) 25

Learning Outcomes:

1. Use and rearrange the equation

F
p= to calculate pressure.
A
2. Carry out an investigation to look at the link between surface area and pressure.
3. Research how surface area is used to reduce/increase the pressure in everyday
life.
Pressure

Key Ideas
1. Pressure, force and area are linked in the equation:

force
pressure=
area
2. We measure force in Newtons [N], area in meters2 [m2] and pressure in Pascals [Pa].
3. Pascals can also be written as [N/m2]

Worked Examples
1. What pressure is a box of weight 500N exerting on a table if it has a base of area
0.5m2?

2. What force would need to be applied, to exert a pressure of 200Pa using a mallet
with a flat surface area of 10cm2?

Worksheet – Calculating Pressure

Pressure and Density – Science (Physics) 26

Complete the questions below using the equation you have just learnt. You must show all
of your working [equation, substitution, solution and units]
1. A box has a weight of 12N and the bottom of the box is 0.5m2. What is the pressure
the box exerts on the floor?

…………………..

2. A bronze statue weighs 2400N and has a base that is 2m2. What is the pressure the
statue exerts on the floor?

…………………..

3. The base of a box is 1.2m by 10m. It weighs 360N. What is the pressure exerted on
the floor by the box?

…………………..

4. What is the weight of an object that has a base which is 3 m2 and which exerts a
pressure of 21 Pa?

…………………..

5. To pop a balloon you stab it with a pencil. If the area of the pencil tip is .0002m 2 and
the pressure you need to apply to the balloon is 1000 Pa. How hard (what force)
must you push on the pencil to make the balloon pop?

…………………..

6. A round tube weighs 300N. If the tube is stood on end it pushes down on the floor
with a pressure of 26Pa. What is the area of the base of the tube?

…………………..

7. The pressure a box pushes down on the floor is 560Pa. If the box weighs 400N what
is the area of the base of the box?

Pressure and Density – Science (Physics) 27

 …………………..
8. A box that is 2m x 2m x 2m size would need to weigh how much in order to create a
pressure of 55Pa on the floor?

…………………..

9. What does a car weigh if its tires cover an area of 0.8m2 and each tire exerts a
pressure of 2300Pa on the ground?

…………………..

10. If the inside of a container has a base area of 20 cm2, what pressure is the container
creating if it contains 176N worth of food?

…………………..

11. What is the weight of an object that has a base which is 6 m2 and which exerts a
pressure of 2.4 MPa?

…………………..

12. A statue weighs 6kN and has a base that is 1.2m2. What is the pressure the statue
exerts on the floor?

…………………..
13. A box has a weight of 11.3kN and the bottom of the box is 65cm2. What is the
pressure the box exerts on the floor?

…………………..

Pressure and Density – Science (Physics) 28

 F
Using p= in the Real World
A
The equation you have learnt this lesson is seen throughout
industry and nature.

Camels Feet Knife blades _________________

What is it? What is it? What is it?

………………………………. ………………………………. ……………………………….
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………………………………. ………………………………. ……………………………….
………………………………. ………………………………. ……………………………….

F F F
How does it link to p= ? How does it link to p= ? How does it link to p= ?
A A A
………………………………. ………………………………. ……………………………….
………………………………. ………………………………. ……………………………….
………………………………. ………………………………. ……………………………….
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………………………………. ………………………………. ……………………………….
………………………………. ………………………………. ……………………………….
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………………………………. ………………………………. ……………………………….
………………………………. ………………………………. ……………………………….

Use your laptops, research the first two examples and then
see if you can find one of your own!

Finished? Head to page 36 to try the STRETCH.

Pressure and Density – Science (Physics) 29

5: Pressure in Fluids
Calculations Recap Quiz
Use the knowledge you have gained in previous lessons to answer the following questions:

1. A box has a weight of 225N and the bottom of the box is 1.7m2. What is the pressure
the box exerts on the floor?

……………… (3)
2. What is the density of an object which takes up a volume of 67cm3 and has a mass of
750g?

……………… (3)
3. What volume of salt water do you if have if it has a mass of 650kg and a density of
1200 kg/m3?

……………… (3)
4. What is the weight of an object that exerts 5kPa of pressure over and area of 2m 2?

……………… (3)
3 3
5. Stretch: An object has a density of 1200kg/m and takes up a volume of 2.5m . What
pressure will this object exert over an area of 0.5m2?

………………

Score [ /12]

Pressure and Density – Science (Physics) 30

Learning Outcomes:

1. Understand that pressure in fluids acts equally in all directions as long as the
liquid is note moving.
2. Use and rearrange the equation
p=h× ρ × gto calculate the pressure difference in a liquid.
3. Describe the factors affecting the pressure experienced in a fluid.
Pressure in fluids

Key Ideas
1. Pressure, depth, density and g are linked in the equation
p=h× ρ × g
2. The pressure that is experienced in a fluid is only affected by depth and the fluid
density (not the size of the object or container).
3. Depth is always measured in meters [m], density in [kg/m3] and g = 10N/kg.
Worked Examples

Pressure and Density – Science (Physics) 31

 1. Sketch the expected paths for the water coming out of the container below:

2. What would be the pressure difference felt by a scuba diver who dives 50m below
the surface of the ocean? [density of sea water is 1200kg/m3]

3. An object is submerged under an unknown liquid. At a depth of 20cm it experiences

a pressure difference of 2000Pa. What is the density of the unknown liquid?

4. A submarine experiences a pressure of 316kPa while submerged under sea water

[density = 1200kg/m3]. If atmospheric pressure is 100kPa, how deep is the scuba
diver?

Pressure and Density – Science (Physics) 32

Worksheet – Calculating Pressure
Complete the questions below using the equation you have just learnt. You must show all
of your working [equation, substitution, solution and units]
1. What is the pressure difference experienced by a fish that descends 2 m in fresh
water (density 1000 kg/m3).

…………………..

2. What is the pressure difference experienced by a fish that descends 5 m in salt water
(density 1028 kg/m3).

…………………..

3. A large tank contains water. Water has a density of 1000 kg/ m3. Calculate the
pressure due to the water at a depth of 5 m.

…………………..

4. What is the pressure difference experienced by a scuba diver that rises from 10 m
below the surface to 2 m below the surface (in salt water, density 1028 kg/m3).

…………………..

5. A balloon in submerged in water (density = 1000 kg/3) and experiences a pressure

difference of 5000Pa. How deep is the balloon?

…………………..

6. A rock is submerged into an unknown liquid. At a depth of 1.8m it experiences a

pressure of 14000 Pa. What is the density of the unknown liquid?

…………………..

Pressure and Density – Science (Physics) 33

 7. You find yourself swimming on an unknown planet. You dive down to a depth of 6m
in a body of water (density = 1000kg/m3) and experience a pressure of 28kPa. What
is the value of g on this planet?

…………………..

8. A fish is placed into a strange liquid and dives down to 20cm below the surface. At
this depth it experiences a pressure of 1.2MPa. What is the density of this strange
liquid?

…………………..

9. A can of soda can withstand a pressure of 650kPa before it is crushed. If it is

submerged in seawater (density = 1028 kg/m3), at what depth will the can be
crushed?

…………………..

10. Sketch on the expected water level in the other parts of the system below:

Explain the decision you have made.

………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………
………………………………………………………………………………………………

Pressure and Density – Science (Physics) 34

Stretch Worksheet – Lemons and Limes
When you put lemon in water, it floats! However, when you put a lime in water, it sinks! Use
your laptop to research the following questions?

 In what way are lemons and limes different?

 Why does a lemon sink?
 Why does a lime float?

[Stuck: Try visiting the websites below to get you started!]

PROOF! https://www.youtube.com/watch?v=HMv42HMJyJE

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https://www.bestfoodfacts.org/lemons-float-limes-sink/

https://blogs.surrey.ac.uk/physics/2012/04/10/lemons-and-limes-even-theoreticians-
sometimes-do-experiments/

Pressure and Density – Science (Physics) 35

Stretch Worksheet – Icebergs

Every iceberg that we can see from land is in fact only 10% of the entire iceberg! 90% of the
iceberg is actually submerged under the ocean!
Use your laptop to research the following questions

 Why does 90% of an iceberg get submerged and not 50%?

 How can something as big as an iceberg floats?
 What happens to the water level if an iceberg melts?

[Stuck: Try visiting the websites below to get you started!]

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http://www.bsharp.org/physics/icebergs

https://beyondpenguins.ehe.osu.edu/issue/icebergs-and-glaciers/all-about-icebergs

Pressure and Density – Science (Physics) 36

Stretch Worksheet – Walking on water

Research an answer to the question:

‘Could a person theoretically walk on water?’

Questions to think about:

 What pressure can be exerted on the surface of water before something sinks?
 Could you increase the area of your feet?
 Would the type of water make a difference?

[Stuck: Try visiting the websites below to get you started!]

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https://www.youtube.com/watch?v=JkS1ymQ73oc

https://www.livescience.com/32670-could-humans-walk-on-water.html

Pressure and Density – Science (Physics) 37

 Pressure and
Density

Past Paper
Questions
Q1.

A student measures the diameter of a coin.

She uses the digital caliper shown in the photograph.

Pressure and Density – Science (Physics) 38

The digital caliper gives readings to the nearest 0.01 mm.
(a) The student measures the diameter of the coin eight times.
Her readings are shown below.

(i) Circle the anomalous reading.

(1)
(ii) Calculate the average diameter of the coin.
(3)

Average = ........................................................... mm
(b) The student wants to find the thickness of a coin.
She takes several similar coins and measures them together as shown.

Pressure and Density – Science (Physics) 39

 She says:

Do you agree with the student?

Explain why.
(2)
............................................................................................................................................
.
............................................................................................................................................
.
............................................................................................................................................
.
............................................................................................................................................
.

(c) The student wants to find the density of the coin.

She uses her values for the diameter and thickness of the coin to calculate its volume.
What else must she do to find the density of the coin?
(3)
............................................................................................................................................
.
............................................................................................................................................
.
............................................................................................................................................
.
............................................................................................................................................

Pressure and Density – Science (Physics) 40

.
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.
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.
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.

(Total for question = 9 marks)

Pressure and Density – Science (Physics) 41

Q2.

The photograph shows two cups of coffee.

The cups are the same size.

One cup is full of coffee, the other cup is half full.

Compare the pressures in the coffee at the bottom of each cup.

(4)
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.
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.
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.
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.
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.
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.
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.
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.

Pressure and Density – Science (Physics) 42

 (Total for question = 4 marks)

Pressure and Density – Science (Physics) 43

Q3.

A student measures the density of water.

She uses a measuring cylinder and an electronic balance.

(a) State the equation linking density, mass and volume.

(1)

(b) A correct unit for density is

(1)
A g/cm
B kg/cm
C g/cm2
D g/cm3

(c) Complete the table to show what is measured by an electronic balance.

(1)

Pressure and Density – Science (Physics) 44

(d) Describe how the student should use each instrument to make her measurements
as accurate as possible.
(4)
Measuring cylinder

............................................................................................................................................
.
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.
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.

Electronic balance

............................................................................................................................................
.
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.
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.

(e) The student wants to make sure her experiment is a fair test.
(i) State one factor that she should keep the same throughout her experiment.
(1)
............................................................................................................................................
.

(ii) Why is it important that she keeps this factor constant?

(1)
............................................................................................................................................
.
............................................................................................................................................
.

(Total for question = 9 marks)

Pressure and Density – Science (Physics) 45

Q4.

A student investigates the density of a liquid.

The student uses scales that show mass to the nearest gram.
The student uses a measuring cylinder that is marked with volume in cm3.

First the student puts an empty measuring cylinder on the scales.

Then the student puts some liquid into the measuring cylinder.

Then the student looks at the level of liquid in the measuring cylinder.

Pressure and Density – Science (Physics) 46

(a) Complete the results table for this investigation by transferring the information given
opposite.
(6)

(b) Show how the student should use these results to calculate the density of the liquid.
(2)

(c) Suggest two ways in which the student could improve the investigation to give a
more accurate value for the density.
(2)
1 ................................................................................................................................................
............................................................................................................................................
.
............................................................................................................................................
.
2 ................................................................................................................................................
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.
............................................................................................................................................
.

Pressure and Density – Science (Physics) 47

 (Total for question = 10 marks)

Pressure and Density – Science (Physics) 48

Q5.

A student places a pile of coins on a table, as shown in photograph A.

There are 8 coins in the pile.

The weight of each coin is 0.036 N.
The area of each coin is 0.0013 m2.
(a) (i) State the equation linking pressure, force and area.
(1)

(ii) Calculate the pressure on the table caused by the pile of coins.
(2)

Pressure = ........................................................... Pa

Pressure and Density – Science (Physics) 49

 (b) The student then spreads the 8 coins out on the table as shown in photograph B.

(i) Describe how this affects the total force from the coins on the table.
(2)
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.
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.
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.
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.
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.

(ii) Explain how this affects the pressure on the table caused by the coins.
(2)
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.
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.
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.
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.

Pressure and Density – Science (Physics) 50

 ............................................................................................................................................
.

(Total for question = 7 marks)

Pressure and Density – Science (Physics) 51

Q6.

The photograph shows two containers that store rainwater.

The containers have taps that are joined by a pipe.
The taps are closed.

The diagram shows the water levels inside the containers.

(a) The density of water is 1000 kg/m3.

(i) State the equation linking pressure difference, height, density and g.
(1)

(ii) Calculate the pressure that the water causes at the base of container A.
(2)

pressure = ...................................... Pa

Pressure and Density – Science (Physics) 52

(b) When the taps are opened, water flows in the pipe for some time. The diagram
shows the final water level in container A.

(i) Complete the diagram to show the final water level in container B.
(1)
(ii) Explain why the water starts to flow and then stops.
(3)
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(Total for question = 7 marks)

Pressure and Density – Science (Physics) 53

 Pressure and
Density

Spec Point
Notes
Pressure and Density – Science (Physics) 54
 Electromagnetic Spectrum Specification Notes

5.01 use the following units: degree Celsius (°C), Kelvin (K), joule (J), kilogram (kg),
kilogram/metre3 (kg/m3 ), metre (m), metre2 (m2 ), metre3 (m3 ), metre/second (m/s),
metre/second2 (m/s2), newton (N) and pascal (Pa)

Pressure and Density – Science (Physics) 55

5.03 know and use the relationship between density, mass and volume:
mass
density =
volume

m
ρ=
V

Pressure and Density – Science (Physics) 56

5.04 practical: investigate density using direct measurements of mass and volume

5.05 know and use the relationship between pressure, force and area:
Force
Pressure=
Area

F
P=
A

Pressure and Density – Science (Physics) 57

5.07 know and use the relationship for pressure difference:

pressure difference = height × density × gravitational field strength

P=h× ρ × g

Pressure and Density – Science (Physics) 58