The Incredible Energy Review Quiz

Insulating the walls and roof of your house reduces heat loss mainly by reducing

• Convection

• Conduction

• Radiation

• Evaporation

Answer explanation

Roughly 35% of all heat loss in a home occurs through the walls, mainly through conduction.

Filling the space between the outside and inside walls with insulating material reduces heat loss.

In an experiment you have tested cardboard and bubblewrap how well they can keep the heat in a soda can. For the experiment is NOT important that:

• the water in all cans is not at the same starting temperature

• you have different liquids in the cans, for example oil or water

• you have different sized cans

• you have a different amount of water in each can

Answer explanation

the starting temperature can be different -- important is how much heat was lost from start to finish (that is, the difference)

Older-style light-globes contains a metal wire through which electricity flows. The electricity is mostly converted into:

• electric energy

• light energy

• heat energy

• magnetic energy

Answer explanation

About 90% of the electrical energy is transformed into heat -- not light!

Look at the graph (click). Which material is the best insulator (can keep the heat the best/longest)?

• No insulation

• Cotton wool

• Polystyrene foam

• This is a trick question!

Answer explanation

Polystyrene can keep the temperature the longest!

You are roasting marshmallows in a campfire with a metal rod. By which method is heat moving along the rod?

• Conduction

• Convection

• Radiation

• Evaporation

Answer explanation

In a metal, the metal atoms transfer heat energy by bumping into their neighbours (kinetic energy). In addition free electrons can transfer their kinetic energy as well. Metals are therefore very efficient conductors.

After a long drive on your motorbike, you check the pressure and see it has increased. This is because:

• the tyre gets weak as it heats up

• air leaks into the hot tyres

• air molecules move faster when hot

• the tyres expand on heating

Answer explanation

As you drive down the road your tires are rubbing against the asphalt. This generates a fair amount of friction, and friction creates heat increasing the kinetic energy of the particles and hence pressure!

Metal pots and pans often have a wooden or plastic handle. This is because these handles do not:

• support convection easily

• support conduction easily

• support radiation easily

• support teleportation easily

An example of a heat insulator is

• an iron rod

• a copper rod

• an aluminium rod

• a wooden rod

Answer explanation

Dry wood is a good insulator! Metals are not!

When a fire is lit the smoke usually rises into the air. this is caused by

• conduction

• convection

• reflection

• radiation

Answer explanation

Convection -- the transfer of heat by the circulation or movement of the heated parts of a liquid or gas

On a hot day, a black can feels hotter than a white and grey can, because:

• the black can absorbs heat better

• the black can is a better conductor

• the black can reflects the heat radiation better

• the grey and white can radiates the heat better than the black can

Answer explanation

Black absorbs the most and grey the least heat radiation