5.1.1 Energy. Units In physics we define mechanical work as the amount of energy transferred by a force acting through a distance W= F • d d= distance between A and B F= Force applied to move the object F d
5.1.1 Energy. Units Therefore, in this example, the energy that black cartoon has, the express the work that can apply to this box,
5.1.1 Energy. Units Units There are several units of energy that are used in special areas, the most popular are the j, cal and kwh. Joule calorie kwh
5.1.1 Energy. Units Joule (J) is the International System’s unit for work, and is usually expressed in Kj. 1kj is the energy need to raise 100kg 1 meter high 1 meter
5.1.1 Energy. Units Calorie (cal) This unit is usually used to express energy that involves calorific transference. When energy is used in the alimentary industry, it’s usually express in Kcal. In the USA, they write Cal instead of Kcal… In order to heat 1 L of water from 20 to 21 ºC we need 1kcal
5.1.1 Energy. Units A human being needs around 2000 kcal per day of energy to do all the work that it needs.
5.1.1 Energy. Units When you drink a Coke you are absorbing 139 Kcal of energy that is stored in the 39gr of sugar dissolved in the liquid. 139 Kcal 420Kcal 840Kcal
5.1.1 1º Exercise Investigate the energy that these foods have per 100 gr: Solution Yogurt Big Mac Bread Apple Biscuits Orange Fanta Cereals Oil Chips Butter
5.1.1 Energy. Units KiloWatt/hour(kwh) It’s the unit used to measure the electric consumption of an electric installation. When we use a hairdrier of 1000 W for 1h, we have consumed 1 kwh
And this is the summary of the production in a block diagram
5.2.1 Electric energy. Generation Mechanical Energy Electric generation Electric Transformation Primary Energy Electric Transport Water or Air Steam from a combustion, nuclear reaction, solar or geothermal Turbine Generator Transformer
5.2.2 Electric energy. Power Stations Mechanical Energy Electricity High Volt All Power stations will have this elements, now we will see how they move the turbines Water, Wind Turbine Generator Transformer Pylon
5.2.2 Electric energy. Power Stations We use the energy source to create steam pressure to move the turbine Steam Boiler Turbine Generator Transformer Cooling Mechanical Energy Electricity Cold Water Heat Pylon High Volt Steam
5.2.2 Electric energy. Power Stations Mechanical Energy Electricity High Volt We use the primary Energy like wind or water pressure to move the turbine Wind Water Turbine Generator Transformer Pylon
Fuente de energía Producción 2007 (ktep) 2007 % Producción 2008 (ktep) 2008 % 2008/2007 Carbón 5.865 19,3 4.374 14,2 -25,4 Petróleo 143 0,5 127 0,4 -11,2 Gas natural 16 0,1 14 0,0 -10,9 Nuclear 14.360 47,3 15.368 50,0 7,0 Hidráulica 2.342 7,7 2.001 6,5 -14,5 Otras energías renovables 7.624 25,1 8.841 28,8 16,0 Total 30.348 100,0 30.725 100,0 1,2
5.1.1 1º Exercise Solution Investigate the energy that these foods have per 100 gr: Solution Yogurt 85 kcal Big Mac 498 kcal Bread 250kcal Apple 59 kcal Biscuits 450 kcal Orange Fanta 58 kcal Cereals 400kcal Oil 900kcal Chips 234kcal Butter 760 kcal
5º Exercise: Make a list of 20 objects indicating the source of energy used and the energy obtained .
For example: TV-Electricity
Back Object Energy Source Energy obtained TV Electricity Light Washing machine Electric energy Mechanical Radiator Electric energy Calorific Computer electric light Fridge Electric energy Mechanical-Calorific Toaster Electric energy Calorific Bulb Electric energy light Dishwasher Electric energy Mechanical Transformer Electric energy Electrical Furnace Chemical energy Calorific
Object Energy source Energy obtained Fridge Electricity Calorific Computer Electricity Light Lamp Electricity Light Microwave Electricity Light- Calorific Toaster Electricity Calorific Vitro Electricity Calorific Deep fryer Electricity Calorific Loudspeaker Electricity Sound Freezer compartment Electricity Calorfic Thermal printer Electricity Calorific Games console Electricity Light Coffee maker Water and Electricity Calorific Calculator Electricity Light Mobile phone Electricity Light Telephone Electricity Sound Car Electricity Mechanical Alarm clock Electricity Sound Dishwasher Electricity Calorific and Mechanical Washing machine Electricity Calorific and Mechanical Alarm Electricity Sound
5.2.1 Exercise Sol. Electric energy. Production
Compare the use of electricity at home with the use of coal, oil, gas, solar, wind, geothermal, uranium.
Coal produces a lot of smoke and dust if we use it to heat or cook. Also requires a lot of space to store it.
Oil is used to heat houses but is really dangerous if we use it to cook or to create light.
Solar energy can be used to heat water, but it doesn’t get really hot. We can use it to cook but it is too slow.
Gas is used to cook but it’s quite dangerous and is more difficult to clean. We use it to heat water and houses.
Wind, geothermal and uranium can’t be used directly at home, so we need to get electricity from them.
5.2.1 Exercise Sol. Electric energy. Production
What do we mean when we say that the electricity is clean?
Electricity is usually defined as clean energy because we can use it at home anytime anyplace. It doesn’t create any dust, gas or smell as does coal, gas or oil.
But we have to remember that to create electricity we are different energy sources like coal, oil, nuclear, etc that have several disadvantages like pollution, nuclear waste, environment destruction, etc.
The water from the river is stored in a dam. The water is released has high energy thanks to the height, so it moves the turbine. The mechanical energy obtained is transformed into electricity inside the generator. This electricity is transformed into high voltage electricity in a transformer. This electricity is connected to the pylons and transmitted to the electric grid
5.2.2 Hydro Power Stations Mechanical Energy Electricity Water high pressure High Volt Water Water Back River Dam Turbine Generator Transformer Pylons River