P1.1 Enegry Transfer by Heating Processes Flashcards Preview

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Flashcards in P1.1 Enegry Transfer by Heating Processes Deck (26)
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1
Q

What is heat radiation?

A

The transfer of heat energy by infrared radiation

2
Q

What is IR emitted/absorbed by?

A

All objects are continually emitting and absorbing IR, it is emitted from the surface of an object

3
Q

How does temperature affect the rate infrared transfer?

A

An object that’s hotter than its surroundings emits more IR than it absorbs (as it cools down), an object that is cooler than its surrounding absorbs more heat than it emits (as it warms up)

4
Q

How does the surface colour and texture of an object affect the rate infrared transfer?

A

Dark, matt surfaces absorb more and emit more IR than light, shiny surfaces which reflect a lot of the IR falling on them

5
Q

What can light, shiny surfaces be used for?

A

Because they reflect IR, they can reduce the amount of energy transferred by radiation

6
Q

What are the three states of matter?

A

Solid, liquid and gas

7
Q

What makes a substance a particular state?

A

The particles are the same, the arrangement and energy of the particles are different

8
Q

Describe the structure of a solid

A

Fixed, regular arrangement - the particles don’t have much energy so they can only vibrate about their fixed position

9
Q

What is the bonding like in a solid?

A

Strong forces of attraction hold the particles together

10
Q

Describe the structure of a liquid

A

The particles are close together, but can move past each other and form irregular arrangements

11
Q

What is the bonding like in a liquid?

A

There are weaker forces of attraction between particles than those in solids

12
Q

Describe the structure of a gas

A

The particles have more energy than those in a liquid/solid, and are able to freely move around in random directions at high speeds

13
Q

Why do solids melt, and liquids boil?

A

Because when you heat a substance you give its particles more kinetic energy so they vibrate or move faster

14
Q

Describe the melting of a solid

A

The particles gain enough energy to be able to move past each other

15
Q

Why can gases and liquids flow, but solids can’t?

A

Because liquid and gas particles can move past each other, whereas solid particles are in a fixed position

16
Q

Why are gases compressible and solids/liquids aren’t?

A

Because when you compress a gas you’re just reducing the distance between the particles and bringing them closer together, solids and liquids can’t really get much closer

17
Q

What is conduction?

A

When you heat particles in solids, they vibrate more and collide with neighbouring particles and share pass on some of their extra energy

18
Q

If you were to heat one side of a solid, why does the other side also gradually get hot?

A

Due to conduction, the energy is gradually passed all the way through the solid to the other side and increases the amount of heat radiating from the solid’s surface

19
Q

What affects the rate of conduction?

A

The density of the substance, the denser a substance, the closer the particles which means the particles collide more often

20
Q

Why are metals such good conductors?

A

At the hot end, delocalised electrons in the metal gain kinetic energy and move freely through the substance quicker - they then collide with other DE and pass on the energy and so on and so on.

21
Q

Why do metals conduct heat so much quicker than other substances?

A

Because transferring heat by electrons freely moving throughout the substance, is much faster than particles slowly passing on energy to neighbour atoms

22
Q

When does convention occur?

A

When more energetic particles in gases or liquids move from a hotter region to a cooler region - and take their heat energy with them

23
Q

Immersion heaters, heater coils…

A

Heat the water at the bottom of the tank by conduction, these particles then get more energy and move around faster. They move around faster so there is more space between them (the water becomes less dense) - this then results in the less dense water rising above the denser (cooler) water. The colder water sinks towards to the heater coils and rises - and so it goes on

24
Q

Immersion heaters, what happens to the particles at the bottom of the tank?

A

They move around faster so there is more space between them (the water becomes less dense) - this then results in the less dense water rising above the denser (cooler) water.

25
Q

Immersion heaters, when hot water rises…

A

The colder water sinks towards to the heater coils and rises - and so it goes on

26
Q

What ends up happening in an immersion heater?

A

Convection currents going up, round and down, circulating the heat energy around the water