Unit 3

Question 1

What is a thermometer?

Answer 1

A mechanical or electrical device used for measuring temperature.

Question 2

How does a liquid thermometer work?

Answer 2

The liquid in the thermometer heats up and expands and moves up the bore, when it is cooled it compacts and moves down the bore.

Question 3

Who first had the idea to measure temperature in units?

Answer 3

Anders Celsius.

Question 4

What scale do most scientists use?

Answer 4

The kelvin scale.

Question 5

What temperature is absolute zero?

Answer 5

-273.15 degrees celsius.

Question 6

Name four devices used to measure temperature.

Answer 6

Thermocouple, infrared thermogram, bimetallic strip and recording thermometer.

Question 7

What are the four important ideas of the particle model of matter?

Answer 7

• When the temperature increases the speed of the particles increase.
• All substances are made up of tiny particles to small to be seen.
• particles are always in motion.
• particles have spaces between them.

Question 8

Define energy.

Answer 8

The ability to do work and cause change.

Question 9

Define thermal energy.

Answer 9

The energy generated by the movement or vibration of particles.

Question 10

What happens as the temperature of a material rises and falls?

Answer 10

The material will either expand or contract.

Question 11

What are the changes of state?

Answer 11

Liquid to solid is solidification.
Solid to liquid is fusion or melting.
Solid to gas is sublimation.
Gas to solid is sublimation
Gas to liquid is condensation.
Liquid to gas is evaporation.

Question 12

What is evaporative cooling?

Answer 12

A process in with the faster moving particles on the surface of a liquid evaporate into the air; the slower moving particles that are left behind have a lower kinetic energy, decreasing the temperature of the liquid.

Question 13

What happens to the temperature of a substance during a phase change? Explain.

Answer 13

During a phase change the temperature of a substance doesn’t change but the total energy either increases or decreases. This happens because the movement of the particles doesn’t change but the arrangement of the particles does.

Question 14

What is radiation?

Answer 14

The transfer of energy without the movement of matter. The energy transferred this way is called radiant energy or electromagnetic radiation.

Question 15

What is thermal conduction?

Answer 15

The process of transferring thermal energy through direct collision between particles.

Question 16

What is a heat insulator?

Answer 16

Heat insulators are poor heat conductors, such as wood.

Question 17

What is a convection current?

Answer 17

When air nears a heat source it is heated up and rises, then it cools in the air and lowers. The now cool air replaces the hot air near the heat source and the cycle continues.

Question 18

Name seven sources of thermal energy.

Answer 18

Chemical, electrical, mechanical, geothermal, solar, wind, and fossil fuels.

Question 19

What is passive solar heating?

Answer 19

It uses the materials in the structure to absorb, store, and release thermal energy.

Question 20

What is active solar heating?

Answer 20

These systems involve fairly complex mechanical systems and devices called solar collectors to store energy.

Question 21

What is a non-renewable resource?

Answer 21

Resources that take millions of years to form.

Question 22

What is a renewable resource?

Answer 22

Energy resources that can be recycled or replaced by natural processes within 100 years.

Question 23

What is global warming?

Answer 23

The gradual increase in the temperature of the earths atmosphere.

Question 24

What is thermal pollution?

Answer 24

A warming of the environment that results from human activities.

Question 25

What is cogeneration?

Answer 25

A method of energy conservation in witch waste heat or energy from one industry is used by another.

Question 26

What is the boiling point of water? Does it ever change? Explain.

Answer 26

Water boils at 100 degrees celsius at sea level but changes on the altitude and pressure. The lower the pressure, the lower the boiling point.