temperature and heat

Question 1

What is temperature?

Answer 1

The measure of the average kinetic energy of particles in a substance.

Question 2

Name three common temperature scales.

Answer 2

Celsius, Fahrenheit, Kelvin.

Question 3

At what temperature does the Kelvin scale start?

Answer 3

Absolute zero (0 K).

Question 4

What is the triple point of water?

Answer 4

The condition where water exists as a solid, liquid, and gas in equilibrium at 0.01°C and 273.16 K.

Question 5

Which thermometer relies on the expansion of a liquid?

Answer 5

Liquid-in-glass thermometer.

Question 6

What is heat?

Answer 6

The energy transferred between two bodies due to a temperature difference.

Question 7

List three methods of heat transfer.

Answer 7

Conduction, convection, radiation.

Question 8

What is specific heat capacity?

Answer 8

The energy required to raise the temperature of 1 kg of a substance by 1 K.

Question 9

State the formula for specific heat capacity.

Answer 9

Q=mcΔθ.

Question 10

What is latent heat?

Answer 10

The energy required to change a substance’s state without changing its temperature.

Question 11

What is thermal expansion?

Answer 11

Increase in the dimensions of a material when heated.

Question 12

What are the three types of expansivity?

Answer 12

Linear, area (superficial), and volume (cubic).

Question 13

Define linear expansivity.

Answer 13

Increase in length per unit length per degree rise in temperature.

Question 15

Why is expansion jointing important in construction?

Answer 15

To prevent structural damage due to thermal expansion.

Question 15

What causes bridges to expand in hot weather?

Answer 15

The rise in temperature increases the material’s dimensions.

Question 15

: What happens to water as it cools from 4°C to 0°C?

Answer 15

It expands instead of contracting.

Question 15

What is the molecular structure of ice responsible for?

Answer 15

Lower density compared to liquid water.

Question 16

What is the significance of water’s highest density at 4°C?

Answer 16

It allows aquatic life to survive under frozen water.

Question 16

Why does ice float on water?

Answer 16

Ice is less dense than liquid water.

Question 17

What property of water helps regulate Earth’s climate?

Answer 17

High specific heat capacity.

Question 18

What is thermal conductivity?

Answer 18

The rate of heat transfer through a material per unit thickness and area per degree temperature difference.

Question 19

Why are metals good conductors of heat?

Answer 19

They have free electrons that transfer heat efficiently.

Question 20

How does wool keep you warm?

Answer 20

It traps air, reducing heat loss by conduction.

Question 21

What does a low thermal conductivity indicate?

Answer 21

The material is a good insulator.

Question 22

Why are cooking pots made of metal but have wooden or plastic handles?

Answer 22

Metal conducts heat; plastic/wood acts as an insulator to prevent burns.

Question 23

Why is water used as a coolant?

Answer 23

It has a high specific heat capacity, absorbing a lot of heat without a significant temperature rise.

Question 24

What is latent heat of fusion?

Answer 24

Energy required to change a substance from solid to liquid at a constant temperature.

Question 25

What happens to steam during condensation?

Answer 25

It releases latent heat as it changes to water.

Question 26

Why does sweating cool the body?

Answer 26

Evaporation absorbs heat from the body.

Question 27

How does a refrigerator remove heat?

Answer 27

By using the latent heat of vaporisation of the refrigerant.

Question 28

How does the concept of density explain floating?

Answer 28

Objects float if their density is lower than the fluid they are in.

Question 28

Define density.

Answer 28

Mass per unit volume of a substance.

Question 28

Why do hot air balloons rise?

Answer 28

Hot air is less dense than cooler surrounding air.

Question 28

Why do icebergs float?

Answer 28

The density of ice is lower than seawater.

Question 29

What happens to an object’s density when it expands?

Answer 29

its density decreases.

Question 29

Why does water take longer to cool than metal?

Answer 29

Water has a higher specific heat capacity than metal.

Question 30

Define conduction.

Answer 30

Transfer of heat through a material without movement of the material itself.

Question 31

Example of conduction.

Answer 31

Heat traveling along a metal rod from a flame.

Question 32

Define convection.

Answer 32

Transfer of heat by the movement of a fluid (liquid or gas).

Question 33

Example of forced convection.

Answer 33

Heat transferred by a fan blowing warm air.

Question 33

Example of natural convection.

Answer 33

Warm air rising and cool air sinking, as in a land breeze.

Question 34

Define radiation.

Answer 34

Transfer of heat through electromagnetic waves without the need for a medium.

Question 35

Example of radiation.

Answer 35

Heat from the Sun warming the Earth.

Question 36

What is the formula for heat transfer in conduction?

Answer 36

Q=kAΔT/d ​ | d or L. l is the length. d is teh thickness. ## Footnote K represent thermal conductivity. A is the cross sectional area of the material si unit for K=W/m⋅K (Watts per meter per Kelvin). SI unit of A (area)=𝑚^2(square metres). SI unit of d is metres(m) ΔT i sthe temperature difference