How we can save energy?

By:Antonela Pavel7th gradeScoala Gimnaziala Magura

What is energy?• Energy is the ability to do work. Taking

your dog for a walk, eating, playing and doing your homework are way to use energy.

• Energy is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems. However, this must be understood as an overly simplified definition, as the laws of thermodynamics demonstrate that not all energy can perform work.

History• The word energy derives from the Greek

ἐνέργεια, which possibly appears for the first time in the work of Aristotle in the 4th century BCE.

• The concept of energy emerged out of the idea of vis viva (living force), which Gottfried Leibniz defined as the product of the mass of an object and its velocity squared; he believed that total vis viva was conserved.

• In 1807, Thomas Young was possibly the first to use the term "energy" instead of vis viva, in its modern sense. Gustave-Gaspard Coriolis described "kinetic energy" in 1829 in its modern sense, and in 1853, William Rankine coined the term "potential energy".

Units of energy We can measure energy in different units:In Joules(J).In kilojoules(kJ),that are used to express larger

quantities of energy(1000 J=1kJ).In calories(cal), that often measures heat energy.In kilocalories(kcal), that are used to express larger

quantities of heat. Calories and Joules measure different units of

energy: 1cal=4.18J

Types of primary Energy

Wind Energy Hydroelectric Solar Energy Geothermal Energy Nuclear Energy

1. Wind energy• Wind power is the

conversion of wind energy into a useful form of energy, such as using: wind turbines to make electrical power, windmills for mechanical power, wind pumps for water pumping or drainage, or sails to propel ships.

Wind energy Advantages:It’s unlimited and non-polluting.The cost of building and maintaining a wind

farm is low. Disadvantages:It’s a variable source of energy.Wind turbines are hazard for birds.Wind turbines produce noise pollutions.

2. Hydroelectric1. Hydropower or water power is

power derived from the energy of falling water, which may be harnessed for useful purposes.

2. History: Early uses of waterpower date back to Mesopotamia and ancient Egypt, where irrigation has been used since the 7th millennium BC and water clocks had been used since the early 2nd millennium BC.

3. Solar energy• Solar energy can be captured by ray panels

connected to the systems which warm water or produce electricity.

• Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar energy technologies include solar heating, solar photovoltaics, solar thermal electricity and solar architecture, which can make considerable contributions to solving some of the most urgent problems the world now faces.

Solar Energy Advantages:It’s clean.Big power stations are not needed.It’s unlimited Disadvantages:It’s a variable source of energy.Solar panels are expensive.

4. Geothermal energy • It uses the temperature of the water under

the ground, that is pumped to the surface to heat homes or greenhouses or to produce electricity.

• Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The Geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%).The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.

5. Nuclear energy

• Nuclear energy is the energy released by reactions involving the nuclei of atoms. We transform nuclear energy into electricity in nuclear power stations.

Types of secondary energy

Electrical Energy Thermal Energy Light Energy Sound Energy Chemical Energy

1. Electricity • Electric potential energy,

or electrostatic potential energy, is a potential energy (measured in joules) that results from conservative Coulomb forces and is associated with the configuration of a particular set of point charges with in a defined system.

2. Thermal energy • Thermal energy is the part of the

total internal energy of a thermodynamic system or sample of matter that results in the system temperature. This quantity may be difficult to determine or even meaningless unless the system has attained its temperature only through cooling, and not been subjected to work input or output, or any other energy-changing processes.

3. Light energy• Solar energy, radiant

light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar energy technologies include solar heating and solar photovoltaics.

5. Sound energy• Sound energy is associated with wave

transmited by the air and produced by vibrations objects. We can say that sound energy is a form of mechanical energy.

6. Chemical energy• Chemical energy is the part of energy in a

substance that can be released by a chemical reaction. It’s stored in substances and it can be absorved during chemical processes.

We can save energy!!!

1.Do you have a shower? If you have a shower: You’re clean and green. You

know that it’s important to save water! If you don’t have a shower: Baths use a lot more

water than showers. Take showers, not baths and you’ll save enough water each week for 1000 cups of tea!

2.Is the tap running when you clean your teeth?

• YES??? Did you know that 10-14 litres of water comes out every minute? If you switch the tap off you can save a lot of water.

• NO??? You are saving a lot of water 10-14 litres of water comes out every minute!

3.Do you turn off the monitor when you’re not using the computer?

• YES??? It saves energy, and it also means the monitor will last longer.

• NO??? Screen-savers don’t save much energy. You should switch your monitor off if you are not using it.

4.Do you write on both sides of a piece of paper?

• YES??? It’s clear that you love trees! Make sure that you only print things when you really need to. You can buy recycled paper too.

• NO??? Cutting down trees is a real problem for the environment. Remember not to waste paper!

5.Are more than 2 electrical things on your room at the same?

• YES??? If you are using lots of electrical things, then you are using lots of energy. Make sure you switch things off if you don’t need them-you’ll help you parents save money too.

• NO??? You are really thinking about how much energy you use.

6.Is your TV on standby when you’re not watching it?

• YES??? When TVs are on standby they are still using energy. You should switch all electrical things off.

• NO??? You know that electrical things still use energy when they are on standby.

7.Do you turn off the lights when you leave a room?

• YES??? Make sure you use energy saving light bulbs too, and you will save more energy.

• NO??? You are wasting energy if you leave the lights on in the house. Remember to switch them off when you leave a room.

8.Do you open the window when the heater or air-conditioner is on ?

• YES??? If you open a window, switch off the heater or air-conditioner or you are wasting energy.

• NO??? You know that it doesn’t make any sense to open a window when the heater or air-conditioner is on.

Ways to save energy

• Turn off the lights when you leave a room.• Use only rechargeable batteries that are used

many times.• Use more imaginations and less electronic

games.• Ask your parents to use energy saving light

bulbs.

More imagination

Rechargeable batteries

Saving light bulbs

The end