Energy

Question 1

What is heat

Answer 1

Heat is the total amount of thermal energy in an object

Question 2

What is temperature

Answer 2

The average amount of energy in an object or how hot or cold an object is

Question 3

What is the law of conservation of energy

Answer 3

Energy cannot be created or destroyed, only changed or transferred

Question 4

Thermal energy always moves from _________ to ___________ places

Answer 4

hotter to colder

Question 5

How is thermal energy transferred in solids

Answer 5

Conduction

Question 6

How is thermal energy transferred in liquids

Answer 6

Convection

Question 7

How is thermal energy transferred in gases

Answer 7

Radiation

Question 8

Explain how conduction happens

Answer 8

In solids, particles vibrate in fixed position when heated. Conduction occurs when a solid is heated allowing the bottom particles to vibrate. The particles then transfer these vibrations to the other particles

Question 9

Why are pans made of metal when cooking.

Answer 9

This is because metals are good conductors meaning they allow heat to pass through them. In this case, it allows the food to cook quicker because the heat is being applied to it.

Question 10

Why are clothes for cold weather made from insulating materials.

Answer 10

This is because insulators don’t allow heat to pass through them.

Question 11

Explain how convection happens

Answer 11

Convection occurs when heat is transferred through the movement of liquids/gases. As the fluid heats up, it becomes less dense and rises. Cooler, denser fluid sinks to take its place, creating a pattern knwon as the convection current. This cycle continues, transferring heat through the fluid.

Question 12

Why does convection happens in liquids and gases but not solids

Answer 12

This is because liquids and solids can move but solids stay in a fixed position

Question 13

What is radiation

Answer 13

Radiation is the transfer of heat through electromagnetic waves without needing a medium

Question 14

What are some features of the best emmiters and absorbers of radiation

Answer 14

1. They are dull
2. They are black
3. They have a large surface area

Question 15

What are some features of the worst emmiters and absorbers of radiation

Answer 15

1. They are shiny
2. They are white or silver
3. They have a small surface area

Question 16

How does cooling down happen through evaporation

Answer 16

Evaporation happens when heat is applied and liquids change to gas. In this process, the highest energy particles escape the liquid and turn to gas, reducing the thermal energy.

Question 17

Explain how our body loses heat through sweat even though the sweat is the same temperature as the body

Answer 17

When we are too hot, our body produces sweat and transfers thermal energy from the body to the sweat. When the sweat evaporates, the highest energy particles leave, cooling our bodies.

Question 18

Why does perfume feel colder than water

Answer 18

Perfume has weaker forces than water, meaning it evaporates quicker. This also means that it removes thermal energy quicker than water, producing a cool feel

Question 19

What are shiny, white or silver surfaces good at

Answer 19

Reflecting radiation away