TECHNOLOGY 9th grade

Raw materials These are materials extracted from nature and used to make goods. These can be vegetables,minerals and animals. Vegetables:wood, cotton, cereals,fruits, vegetables, seeds etc. Animal : wool,leather,silk,milk Mineral: iron, copper, gold, petroleum The environmental impact created by the extraction of materials can sometimes be degradating and contaminating. Mineral extraction has the biggest environmental impact. It damages waters so as the land where it is excavated.

Industries generate big quantities of residues but some parts are recuperated. Construction residues can be recuperated by using them as land fillings and also as bases for other constructions. Dangerous residues are those that are toxic.They damage the land ,water ,air ,and people around causing diseases including cancer.

Residual water is the one that comes from industries Residual water is the one that comes from industries.it needs to be treated before it is thrown away because it is contaminating. Nowadays some products are designed with some packages that are biodegradable. Others are made reusable on purpose.While many others are made with recyclable materials . All of these to promote reusing , recycling and reducing. Residues need to be reused or recycled. Many countries are using these as energy source as in biomass.

Geothermal energy Heat from the earth can be used as an energy source in many ways, from large and complex power stations to small and simple pumping systems. This heat energy, known as geothermal energy, can be found almost anywhere. Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.

This thermal energy is contained in the rock and fluids beneath Earth's crust. It can be found from shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma.  Many regions of the world have geothermal energy . It’s better than fossil fuels because : cheaper it’s a solution to reducing dependence on fossil fuels prevents global warning Health problems that result from their use.

Geothermal water from deeper in the Earth can be used directly for heating homes and offices.Some U.S. cities pipe geothermal hot water under roads and sidewalks to melt snow.  Geothermal energy is generated in over 20 countries. In Iceland, many of the buildings and even swimming pools are heated with geothermal hot water. Iceland has at least 25 active volcanoes and many hot springs and geysers.  

Geothermal plants account for more than 25 percent of the electricity produced in both Iceland and El Salvador.

FOSSIL FUELS There are three major forms of fossil fuels: coal, oil and natural gas. All three were formed many hundreds of millions of years ago before the time of the dinosaur. Fossil fuels are hydrocarbons, primarily coal, fuel oil or natural gas, formed from the remains of dead plants and animals. As the trees and plants died, they sank to the bottom of the swamps of oceans. They formed layers of a spongy material called peat. Over many hundreds of years, the peat was covered by sand and clay and other minerals, which turned into a type of rock called sedimentary. More and more rock piled on top of more rock, and it weighed more and more. It began to press down on the peat. The peat was squeezed and squeezed until the water came out of it and it eventually, over millions of years, it turned into coal, oil or petroleum, and natural gas.  

There are 3 main fossil fuels: Coal is typically found as layers (coal beds) or veins Natural gas is a combustible mix of hydrocarbon gases. It’s colorless and consists mainly of methane . 3. CRUDE OIL or condensate. Petroleum and liquified petroleum gas (LPG) are the most common types of fuel obtained from oil extraction and refining.  Petroleum is a liquid fuel made of hydrocarbons and other liquid organic compounds Liquified Petroleum Gas or LPG is heavier than natural gas. Although gaseous under normal atmospheric conditions, LPG is stored under modest pressures in its liquid form and so can be more easily transported and stored.

Co coal

Disadvantages of fossil fuels Cost Pollution  global gases warming Becoming hard to find Renewable resources are usually much cleaner.

Renewable Renewable energy is generally defined as energy that comes from resources which are naturally replenished on a human timescale, such as sun,wind, rain, tides, waves, and geothermal heat. Renewable energy replaces conventional fuels in four distinct areas: electricity generation, air and water heating/cooling, motor fuels. Increasing government support is creating renewable energy legislation. There is also private  commercialization.

Nuclear energy A clean, safe way to make electricity. It does not burn any fuel like coal so there are no pollutants released into the air. Nuclear energy is energy that is stored in the nucleus or center core of an atom. The nucleus of an atom is made of tiny particles of protons and neutrons .The electrons move around the nucleus. The nuclear energy is what holds the nucleus together.

Nuclear power plants use fission to make electricity Nuclear power plants use fission to make electricity. By splitting uranium atoms into two smaller atoms, the extra energy is released as heat. Uranium is a mineral rock, a very dense metal, that is found in the ground and is non-renewable, that means we can't make more. It is a cheap and plentiful fuel source. Power plants use the heat given off during fission as fuel to make electricity.

Hydroelectric energy Hydroelectric power, or hydroelectricity, is generated by the force of falling water. (Hydro comes from the Greek word for water.) It’s one of the cleanest sources of energy, and it’s also the most reliable and costs the least. Hydroelectric energy has been in use for thousands of years. Ancient Romans built turbines, which are wheels turned by flowing water. Roman turbines were not used for electricity, but for grinding grains to make flour and breads. 

The water is held behind a dam, forming an artificial lake, or reservoir. The force of the water being released from the reservoir through the dam spins the blades of a giant turbine. The turbine is connected to the generator that makes electricity as it spins. After passing through the turbine, the water flows back into the river on the other side of the dam.

The excess of water falls on top of the dam and it runs to the river. Disadvantages : The reservoir can cause flooding when there is excess of water in it because of weather problems. If there is draught,the level of water will not be high enough.Then there will be no generation of electricity.