Thermal Energy Test

Question 1

Temperature

Answer 1

the average kinetic energy of molecule

Question 2

Kinetic Energy

Answer 2

energy of motion

Question 3

Thermal Expansion

Answer 3

when temperature rises, molecules move rapidly and spread apart

Question 4

Thermal Contraction

Answer 4

when temperature lowers, molecules move slowly and is closer together

Question 5

Potential Energy

Answer 5

the attraction between molecules, more mass more potential energy

Question 6

Thermal Energy

Answer 6

Potential + Kinetic energy

Question 7

Heat

Answer 7

Movement of energy from high to low temepratures

Question 8

Thermal Equilibrium

Answer 8

there is no temperature difference, (no temp. exchange)

Question 9

Conduction

Answer 9

heat transfer through direct contact

Question 10

Convection

Answer 10

heat transfer from one location to another through liquid or gas

Question 11

Radiation

Answer 11

heat transfer through electromagnetic radiation (UV Lights)

Question 12

Conductors

Answer 12

materials that allows heat to transfer easily

Question 13

Insulators

Answer 13

(opposite of conductors) does not pass heat easily

Question 14

Specific Heat

Answer 14

describes the amount of energy in Joules from 1kg to 1C (Inversely proportional)

Question 15

Thermodynamics

Answer 15

relationship between work and heat

Question 16

1st Law of Thermodynamics

Answer 16

energy cannot be created or destroyed, only transformed/transferred

Question 17

2nd Law of Thermodynamics

Answer 17

heat flows from low to high temp

Question 18

Work

Answer 18

force upon an object causing it to move

Question 19

When a liquid is cooled, the liquid molecules-

Answer 19

(B) move slower than before, (C) experience thermal contraction

Question 20

heat transfer that occurs in outer space

Answer 20

(C) radiation

Question 21

an insulator is a material that has molecules that

Answer 21

do not transfer heat easily

Question 22

The following objects are all heated from 10°C to 30°C. Which object will transfer the most energy to your hand?
a. 5kg apples
b. 2kg apples
c. 5kg gold
d. 2kg gold

Answer 22

5 kg apples

Question 23

Two objects of the same material but different masses are subjected to the same thermal energy input.

Answer 23

object with less mass will have more temperature change

Question 24

All of the following are examples of conductors except ___.
a. silver
b. water
c. air
d. aluminum

Answer 24

air

Question 25

A 80°C object and a 60°C object sit (not touching) in a 21°C environment. Which best explains what will happen?

Answer 25

the environment will get warmer

Question 26

Which is an example of heat transfer by convection?

Answer 26

water boiling in a pot

Question 27

Which of the following is an example of energy conservation? a. An apple hangs suspended from a tree. b. A person stands on tiptoes. c. A car waits at a red light. d. A hockey puck slides to a stop due to friction.

Answer 27

a hockey puck slides to a stop due to friction

Question 28

When energy is transferred as heat, the amount of usable energy ___.

Answer 28

remains the same

Question 29

How are temperature and kinetic energy related?

Answer 29

temperature is the measurement of the average kinetic energy of molecules

Question 30

Describe what happens to motion and spacing of molecules when heated or cooled for a: a. liquid b. solid c. gas

Answer 30

the molecules always move slow and get closer (contract) when cooled. When heated, they expand and move around faster.

Question 31

what does a thermometer measure

Answer 31

temperature

Question 32

Describe characteristics of the three temperature scales including freezing and boiling point of water for each.

Answer 32

Boiling Point- Kelvin- 373 Celsius- 100 Fahrenheit- 212 Freezing- Kelvin-273 Celsius- 0 Fahrenheit- 32

Question 33

using the ideas of thermal expansion and contraction, describe how a thermometer works

Answer 33

temperature increase cause liquid inside thermometer to expand, therefore temperature rises. Temperature decrease causes liquid inside to extract, therefore temperature falls

Question 34

what state of matter has the most and least potential energy?

Answer 34

Solid - Most Gas - Least

Question 35

what 2 types of energy do molecules possess

Answer 35

potential and kinetic

Question 36

explain why thermal energy and temperature, though related, are different

Answer 36

Temperature uses kinetic energy while thermal energy uses kinetic and potential energy

Question 37

provide an example of when two substances might have the same temperature but different thermal energy.

Answer 37

A cup of water and a bucket of water. They could both have the same temperature, but the bucket of water is holding more, so it has more molecules.

Question 38

how are heat flow and temperature differences related?

Answer 38

the greater the difference between temps, the more heat will flow

Question 39

which will cool fastest initially in a room temperature room? boiling water or lukewarm water?

Answer 39

boiling water

Question 40

will heat flow between two objects touching that have the same temperature?

Answer 40

no because no heat can be exchanged if they are the same temperature (they've reached thermal equilibrium)

Question 41

which direction does heat flow? give an example

Answer 41

heat flows from high to low. In a pot of boiling water, the hot water from the bottom rises to the top as the the cooler water from the top sinks down to the bottom

Question 42

three methods of thermal energy transfer

Answer 42

conduction, convection, radiation

Question 43

do all objects emit the same amount of radiation? why or why not?

Answer 43

hotter objects transfer more heat through radiation since they have more heat to release

Question 44

why does conduction primarily occur in solids

Answer 44

molecules are very close in solids, therefore heat is easier to transfer

Question 45

what is the difference between conductors and insulators?

Answer 45

conductors allow heat to transfer easily while insulators don't

Question 46

examples of conductors

Answer 46

metal, aluminum, silver

Question 47

example of insulators

Answer 47

glass, air, rubber

Question 48

what kind of material would make tea boil quicker in a kettle

Answer 48

metal

Question 49

what would you use to maximize and minimize heat transfer

Answer 49

Max - metal Min - air

Question 50

If you have several spoons made of conducting materials and insulating materials, which will feel cooler to the touch and why?

Answer 50

metal because it takes thermal energy quicker

Question 51

state wheat her the variable is "inversely" or "directly" proportional to the temperature change a. mass b. specific heat c. thermal energy transferred

Answer 51

mass - inversely; a bucket and a cup of water are over a fire, the cup of water changes faster than the bucket, since there is less mass to heat up specific heat - inversely; the smaller the specific heat, the more temperature change it will have thermal energy transfer - directly; the more thermal energy, the more temperature change

Question 52

Suppose you took a bite of pie that was at a certain temperature. The crust doesn’t burn you but the filling does. Using the idea of specific heat, explain why the filling burned you but the crust didn’t even though they had the same temperature.

Answer 52

The filling needs more energy to cool down, so even though the crust is cooled down, it doesn’t need as much energy as the filling to cool down, so the filling still burns you. The filing transfers more thermal energy because it has less specific energy than the crust.