2NA Science Revision 3

A can of coke from the fridge feels colder than a packet of lemon tea. Why?

• The metal can conducts heat away from our hand more quickly than the cardboard packet.

• The metal can is a better insulator of heat

• The cardboard packet is a better conductor of heat

• The metal can allows coldness to travel quicker to our hand than the packet

Convection of heat happens in

• liquids only

• gases only

• both liquids and gases

• solids

The particles of a substance must _____________ for convection to take place.

• move from one place to another

• decompose

• dissolve in water

• be small

Why does the purple colouring in the heated beaker of water move upwards?

• The hotter and less dense water rises to the top

• The hotter and more dense water rises to the top

• The cooler and more dense water rises to the top

• The cooler and less dense water rises to the top

The fan in the convection oven is to help _______________ during cooking.

• distribute the hot air throughout the oven

• cool down the person cooking in the kitchen

• remove hot air from the oven and release to the surroundings

• take in hot air from the kitchen to the oven

Radiation from the sun is able to reach us because

• the transfer of heat energy can be done even through vacuum in outer space.

• sun rays are very strong and intense

• of the presence of the ozone layer

• of the destruction of the ozone layer due to CFCs

The greenhouse effect happens when

• greenhouse gases trap heat within our atmosphere

• plants are grown in greenhouses

• greenhouse gases allow heat to pass through our atmosphere easily

• acidic gases dissolve in rain water

The ice at the bottom of the test tube took a long time to melt because water is

• a good conductor of heat

• bad conductor of heat

• good conductor of electricity

• bad conductor of electricity

Which container of water have the highest temperature after some time?

• White

• black

Petrol storage tanks are painted white or silver to _________ the radiation from the sun, preventing them from heating up.

• reflect

• absorb

• accumulate

• repel