Natural Science

What is the definition of fossil fuel?

A fuel such as coal, oil or gas that formed underground over millions of years from decaying living material.

What characterizes a non-renewable source of energy?

A source of energy that is limited in supply because it cannot be replenished quickly enough by natural processes.

What is crude oil?

Oil in its naturally-occurring form, processed to make fuels and other products.

What defines a renewable source of energy?

A source of energy that cannot be used up because it is continually replaced by natural processes.

What is hydropower?

Energy from moving water, used immediately or converted into electrical energy.

What is a photocell?

A small device that absorbs solar energy and converts it to electrical energy.

What is potential energy?

Energy that is stored in a system and has the potential to be released.

What is the unit of measurement for energy?

The joule (J), with food energy typically expressed in kilojoules (kJ).

What is the law of conservation of energy?

Energy cannot be created or destroyed — only converted from one form into another.

What is conduction?

Heat transfer between two objects in direct physical contact, moving from the hotter to the cooler object.

What is convection?

The transfer of heat from one place to another by the movement of liquid or gas particles.

What is radiation in terms of heat transfer?

Heat transfer that requires no direct contact and no movement of particles, occurring as heat energy travels across empty space.

What are good conductors?

Materials, mostly metals, that conduct heat quickly.

What is the purpose of insulating materials?

To minimize heat loss in winter or heat gain in summer by slowing heat transfer in or out of a space.

What is energy efficiency?

An energy-efficient appliance uses most of its input energy to produce a useful output, wasting as little energy as possible.

What is the function of a coal-fired power station?

To burn coal to provide the energy needed to generate electricity.

What does a dynamo do?

Converts mechanical kinetic energy into electrical energy, often used in small tools and appliances.

What is biofuel?

Fuel derived from plant materials, such as maize or soybeans, often fermented to produce ethanol.

What happens to energy during burning fossil fuels?

Chemical energy is converted into heat energy, but also releases polluting gases.

What is the renewable characteristic of solar energy?

It is consistently replenished as the sun is expected to shine for billions of years.