8H Energy

Question 1

What is a Shadouf?

Answer 1

A type of lever used by ancient Egyptians

Question 2

What is a machine?

Answer 2

Something that helps us to do work.

Question 3

What can a force do to energy?

Answer 3

A force can transfer energy.

Question 4

When is work done?

Answer 4

When a force is used to transfer energy.

Question 5

What is the unit for energy?

Answer 5

Joules (J)

Question 6

What 2 things affect work done?

Answer 6

Force applied and distance moved

Question 7

What is displacement?

Answer 7

The shortest distance from a start to and end point.

Question 8

What is the equation to calculate work done?

Answer 8

work done (J) = force (N) x distance (m)

Question 9

How do machines make work easier?

Answer 9

They reduce the force needed to make something work.

Question 10

Why isn’t a tractor a human powered machine?

Answer 10

They are powered using sources of energy other than us

Question 11

Why do humans require the use of machines?

Answer 11

There is a limit to how much force we can supply.

Question 12

Give an example of a common machine.

Answer 12

Door handle, toilet flush, tap, pedal bin

Question 13

How does a lever reduce work?

Answer 13

It reduces force by increasing distance.

Question 14

How does a screwdriver help to open a tin of paint?

Answer 14

The screwdriver increases the distance the force is acting over.

Question 15

How do wheels reduce work done?

Answer 15

They reduce friction.

Question 16

What machines are present in a bicycle?

Answer 16

Levers, gears and wheels.

Question 17

What state of matter does conduction occur through?

Answer 17

Solids

Question 18

How do particles in a solid move?

Answer 18

They vibrate in place

Question 19

What is a thermal insulator?

Answer 19

Materials which are not good at allowing the transfer of energy through them.

Question 20

Give an example of a thermal conductor.

Answer 20

Metals

Question 21

Which states of matter does convection occur in?

Answer 21

Liquids and Gases (Fluids)

Question 22

What is a convection current?

Answer 22

A current in a fluid that allows the transfer of heat energy.

Question 23

What does radiation travel as?

Answer 23

A wave

Question 24

Describe the frequency of infrared radiation.

Answer 24

The frequency is lower than red light.

Question 25

Name three places where it is common to have insulation in our homes.

Answer 25

Cookers, fridges, walls, loft, etc.

Question 26

What is something called if energy passes through it at a slow rate.

Answer 26

Insulator

Question 27

In the experiment shown- what is the independent variable?

Answer 27

Material the rod is made from.

Question 28

In the experiment shown- what is the dependent variable?

Answer 28

Time taken for the pin to drop.

Question 29

In the experiment shown- name 1 control variable.

Answer 29

Length of the rod, placement of pin, time heat is applied.

Question 30

When insulating something, why should fluids not be allowed to flow?

Answer 30

Fluids can transfer energy through convection.

Question 31

What type of materials are good at reflecting waves?

Answer 31

Shiny objects.

Question 32

Why do builders put plastic foam between walls for insulation?

Answer 32

The foam contains air pockets- good insulator.

Question 33

Give an example of a use of a thermal conductor.

Answer 33

Saucepans, radiators,

Question 34

Give an example of a use of a thermal insulator.

Answer 34

Food containers, loft insulation.

Question 35

What is the independent variable in this experiment?

Answer 35

The insulation material.

Question 36

What is the dependent variable in this experiment?

Answer 36

Temperature change over time.

Question 37

Why is the experiment carried out on a heat-proof mat?

Answer 37

To minimise heat loss through the base of the can.

Question 38

What is the function of the lid?

Answer 38

To minimise heat loss through convection.

Question 39

Identify a control variable for the experiment.

Answer 39

Number of layers of insulation material, starting temperature, time the temperature was measured.

Question 40

How will you know which material is the best insulator?

Answer 40

The test where the temperature decreased the least.

Question 41

How will the type of material/ number of layers be represented on the graph?

Answer 41

Curves on the same axis

Question 42

Why do we need to draw a graph of our data?

Answer 42

To see any patterns in the data

Question 43

How can you easily measure thermal energy transfer?

Answer 43

Monitor temperature

Question 44

In what direction is thermal energy transferred?

Answer 44

From a warm object to a cooler object

Question 45

What is thermal equilibrium?

Answer 45

An equal temperature in all objects.

Question 46

What is a vacuum flask made from?

Answer 46

2 glass layers covered in a reflective surface.

Question 47

What is a vacuum?

Answer 47

An area with no particles.

Question 48

Why is a vacuum useful?

Answer 48

Thermal energy can not be transferred by conduction of convection through a vacuum.

Question 49

Why is the glass silvered?

Answer 49

To reflect the radiation.

Question 50

What is the function of the lid?

Answer 50

To stop heat loss through convection.