3-2 Heating things up (3.1)

• Natuurkunde
• Middelbare school
• havo, vwo
• Leerjaar 2

Heating things up (3.1)

Heat food up

• The bottom of the metal pan transfers heat to food.
  
• The bottom of the pan is made of a metal wich conducts heat well.
  
• Handle conducts heat poorly.  e.g. wood
  

Insulator

• Wool and polystyrene foam insulate well, because they contain stationary air.
  
• To keep a hot drink hot: Vacume is the poorest conductor of heat possible. e.g. doube-walled cup
  

Convection of heat

• In a fan oven air is blown through the over and transfers heat to the oven dish. 
  

Heating in a house

AIr circulation transports heat through the whole room.

A pump causes water to flow through the radiators.

Radiation of heat

• Grill of an oven transfers heat by radiation.  
  
• A fireplace is also a good example - facing the fireplace, you back gets cold.
  
• The sun also radiates heat.
  

The gulf stream

Due to the heat in Mexico - Amsterdam is hotter.

For climate these gulf streams are very important.

Absorption and refelction:

- Black absorbs the best.

- Shiny objects absorbs poorly, and reflects thermal radiation. White reflects.

- The fire service use heat deflecting suits (layer of alluminium).

In sunny countries are also mostly white houses.

Why are radiators close to the ground?

1. For circulation
2. That the radiation is closer to people
3. That cats can lie on top of them
4. To hang towels on them to dry

Which movie is based on the change in temperature due to gulf streams?

1. The core
2. The day after tomorrow
3. 2020
4. Tornado

Metals are good conductors of heat?

1. True
2. False

With thermal convection only the heat moves: the air stays in the same place.

1. True
2. False

With thermal conduction, only the heat moves: the metal particles stay in place.

1. True
2. False

Only radiation can transport heat without the presence of any matter in between to transport heat.

1. True
2. False

Cold air flows downwards.

1. True
2. False

In a saucepan the heat moves from the outside to the inside of the pan.

1. Radiation
2. Convection
3. Conduction

The sun heats the earth

1. Radiation
2. Convection
3. Conduction

In a stove-top kettle the heat moves from the bottom to the top.

1. Radiation
2. Convection
3. Conduction

An ice cube melts in your hand.

1. Radiation
2. Convection
3. Conduction

Heat is transported from the central heating boiler to the radiators.

1. Radiation
2. Convection
3. Conduction

Which phase best enables thermal convection to take place?

1. solid
2. liquid
3. gas

In which phase is conduction the only means of heat transfer, as convection cannot take place?

1. solid
2. liquid
3. gas

Questions

10 up to 16

When you are done read more about igloos on the internet

:-)

What have you
learned today?