Heat

Question 1

Define “Heat”

Answer 1

Heat is a form of thermal energy possessed by hot bodies measured in joules.

Question 2

Define “Temperature”

Answer 2

Temperature is a measure of how hot or cold something is measured in degrees Celcius

Question 4

Give an example of something that is hot but does not contain a lot of heat energy.

Answer 4

a sparkler spark very hot but is so small it does not contain much energy.

Question 5

What are the three methods of heat transfer?

Answer 5

Conduction, Convection and Radiation

Question 6

Which forms of heat transfer require matter?

Answer 6

Conducton and Convection

Question 7

Which form of heat transfer does not require matter?

Answer 7

Radiation

Question 8

Use the particle theory to explain heat.

Answer 8

When an object is heated its particles move more rapidly because they have more energy

Question 9

Explain, using the particle theory, how hot objects transfer heat to cold objects.

Answer 9

The rapidly moving particles of the hot object transfer some of their energy to the cooler object.

Question 10

What is the coldest temperature possible?

Answer 10

Minus 273 degrees Celcius. All motion of particles stops at this temperature (absolute zero)

Question 11

What three variables govern the amount of heat gained or lost by an object?

Answer 11

Its mass, the change in temperature and what it is made of.

Question 12

Heat is transferred in liquids and gases by _____.

Answer 12

Convection

Question 13

Give an example of a hot object transferring heat to a cooler substance.

Answer 13

An electric kettle element is heated and this heats the water.

Question 14

Heat is transferred in a solid by ________.

Answer 14

Conduction

Question 15

Use the particle theory to explain why heat is moved by convection in gases and liquids

Answer 15

The particles in liquids and gases can move which allows heat to flow in the liquid or gas.

Question 16

Heat is transferred in a vacuum by _______.

Answer 16

Radiation

Question 17

In what form is heat radiated through a vacuum?

Answer 17

Waves

Question 18

What three things can happed to heat radiation when it strikes matter?

Answer 18

Radiation can be absorbed, reflected or transmitted by matter.

Question 19

Use the particle theory to explain how heat is moved by conduction in a solid.

Answer 19

The particles in a solid are fixed and have limited movement. Heat moves by particles vibrating against their neighbouring particles. Some solids are better conductiors than others.

Question 20

Transmitted heat p______ through material

Answer 20

passes

Question 21

Reflected heat b_______ off material

Answer 21

bounces

Question 22

Define “Heat Conductor”

Answer 22

Substances that conduct heat well. Most metals are good conductors.

Question 23

Define “Insulator”

Answer 23

Insulators are poor conductors of heat.

Question 24

What is the colour of material that best absorbs heat?

Answer 24

Dark colours

Question 25

What is the colour of material that best reflects heat?

Answer 25

Light colours

Question 26

What is the colour of material that best emits (loses) heat?

Answer 26

Dark colours

Question 27

What colours are poor emitters of heat?

Answer 27

Light colours

Question 28

Absorbed heat is t_______ i_ by material

Answer 28

taken in

Question 29

Substances _________ or get bigger when they are heated up.

Answer 29

expand

Question 30

Substances ______________ or get smaller when they are cooled down.

Answer 30

contract

Question 31

What causes pressure when gas is sealed in a container?

Answer 31

The particles in a gas move quickly in all directions, but they don’t get far before they bump into each other or the walls of their container. When gas particles hit the walls of their container they cause pressure. The more particles that hit the walls, the higher the pressure.

Question 32

Why does a rise in temperature cause a rise in pressure when gas is sealed in a container?

Answer 32

The particles of the trapped gas move faster and collide with the walls of the container at greater speed and more frequently causing a rise in pressure.