unit10: energy

Energy

What is energy?

What is energy? Energy is the capacity of anobject or body to transform an energy source into work.

The quantity of energy isthe equivalent of the quantity of work.

Units of energy • The international System (IS)

measures energy in joules (J) and kilojoules.

1000 J = 1 KJ

• Heat energy is often measured in units called calories (cal) and Kilocalories (kcal).

1 cal = 4,18 J

Different types of energies

Muscle energyYears ago, muscle energy was the main source of energy, but we have invented different mechanisms and machines that have improved our quality of life.

For example:★Bicycles need our muscle energy when we move the pedals.

★Kitchen appliances need electricity to work, as televisions and computers.

Mechanical Energy

★Kinetic Energy

★Potential Energy

Electrical energy

Electromagnetic energy

Sound energy

Chemical energy

Nuclear energy

Thermal or calorific energy

POWER

t

W is work, measured in joules (J)

t is time, measured in seconds (s)

P= W

P is power, measured in watts (W)

The power of a machine is the quantity of work it can do per unit of time. Power is expressed in the formula:

Transformation of energy

It’s when we transform an initial form of energy into other forms of energy.

Examples: Chemical to electrical energy, luminous to electrical energy...

Energy sources

What is?

Energy sources are natural resources that provide different forms of energy. This energy is transformed for specific uses. They are classified into:

●renewable sources

●non-renewable sources

Renewable energy sources

Hydraulic energy

Solar energy:

➔Termal system:

➔Photovoltaic energy:

Wind energy

Marine energy

➔ Tidal energy:

➔ Wave energy:

➔ Ocean Thermal energy:

Geothermal energy

Biomass

Municipal solid waste

Nuclear energy

Coal

Petroleum

Natural gas

Non- Renewable energies and the environment

Green house effect

Acid Rain

Oil Spills

Nuclear Waste

Rising Water temperature

Atmospheric Pollution

THE ENDBy: Berta Parera, Marta Pera & Guisla Roig.