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SCIENCE revision (Chapter 3.1-energy can be transferred (examples of…
SCIENCE revision
Chapter 3.1-energy can be transferred
All objects have energy.
energy is referred to as the ability to do WORK
energy CANNOT be created or removed.
when energy is passed from one object to another, it is said to be transferred.
examples of objects having energy
moving objects
stretched objects
objects high off the ground
where does energy come from?
all of the energy on earth comes from one source: the sun
the plants on earth absorb the energy from the sun in a process called photosynthesis.
Animals, including humans, than consume the plant and the energy is transferred into us.
the energy helps the animals and humans move and have the ability to walk, this produces heat which warms up the air around them/us.
where does energy go?
most energy that is extra is used to power transportation vehicles.
electric cars are being designed to use energy stored in batteries,rather than using patrol and at the same time making the wheels turn.
public transportation uses energy as well
trams and metropolitan trains transfer the electrical energy from the overhead wires into the motor which makes the wheels move.
energy transfers for entertainment
both CS and DVD players need to transfer energy from the batteries to the wires.
the energy is then transferred into laser light, enabling it to read the information stored on the CD or DVD.
tiny microscopic pits which make up the digital code and the laser, which is a very pure type of light reads the code and transfers it onto the screen and into the speakers.
chapter 3.2 - potential energy is stored energy
potential energy is stored energy in objects that is waiting to be used.
ELASTIC POTENTIAL ENERGY
energy that is stored through stretching or squashing is called elastic potential energy.
example is a trampoline for instance.
a trampoline has the ability to "store" energy or "hold" i, for later use.
the springs and the mat of the trampoline stretch under our weight and hold the energy.
the more it stretches the more energy is stored
the energy is returned to our bodies when the springs and mat return to normal and throw us up into the air.
GRAVITATIONAL POTENTIAL ENERGY
If we lift and object up into the air, it gains gravitational potential energy (GPE)
The larger the mass and the larger the height, the more GPE the object gains
the reason why objects that fall from a bigger distance develope a louder thud and can hurt more, is because as the object falls down, the objects GPE can be transformed into othe forms of energy.
for instance, when a person slides down the slide in a park. the higher they climb the more GPE they get. however, when they SLIDE down, the GPE decreases. instead, the person gains movement energy.
CHEMICAL POTENTIAL ENERGY
this energy, CPE, can be absorbed and released when a particle is triggered with another particle and causes a reaction.
for instance, fuels such as natural gas and patrol provise us with energy as well.
petrol has chemical energy stored in it.
NUCLEAR ENERGY
Nuclear energy involves the reaction at the center of the atoms.
when atoms react in chemical reactions they usually release only small amounts of energy
However, if the center or nuclei of those atoms are made to react, the amount of energy released can become much much larger, having the ability to cause immense destruction.
Chapter 3.3- moving objects have kinetic energy
the energy of movement is scientifically called kinetic energy (KE)
LIGHT ENERGY
the energy moves in small pockets of energy called photons
we see a range of colors in the spectrum such as red, orange, yellow, green. Etc.)
the light we see is part of a larger group called electromagnetic radiation.
this LARGE group includes; ultraviolet light, microwaves and x-rays.
the study of light is called optics/
the main reason life exists on planet earth and not on any other planet is the fact that our atmosphere allows right amounts of the different forms of light energy coming from the sun to reach the surface.
HEAT ENERGY
Heat energy is more "scientifically" known as "thermal energy".
this energy can be generated by friction , burning chemicals, electrical devices. Etc.
for instance, an ice block feels cool because it takes away the thermal energy from our hands.
ELECTRICAL ENERGY
All substances are made up of positive and negative electrical charges that, when separated, have electrical energy.
during separation, this means they are in a state of excitement and are trying to get back together again.
if the positive and negative charges are locked together in one area such as a wire, the separate charges can easily move back together.
As the electrons try to move back together, the electrical energy they had when they separated, get's changed into light, heat or movement that we see in light bulbs, heaters or motors.
SOUND ENERGY
if you are near a source of very LOUD sound, your body begins to vibrate
sound is generated when things vibrate.
vibrations can occur in gasses and even solid things such as speakers.
energy is needed to make sound
energy is a type of kinetic energy.
Chapter 3.5- energy cannot be created or destroyed.
energy cannot be created or destroyed. this is called the law of conservation of energy.
if all the input energy was added together it would be the same as the output but the type of energy may change.
calculating the energy efficiency formula:
efficiency: useful energy output divided by energy input multiplied by 100.
heat and sound waste energy
since no system is 100% efficient, in most cases, the energy that is extra is transformed into heat and sound energy.
when you drop a ball, it starts with gravitational potential energy, which is then transformed into kinetic energy when you drop it. when the ball hits the ground, it makes a noise. the larger the noise is the more sound energy was generated.
if you bounce a ball many time in a row, you may be able to feel the ball warming up. Heat energy has also been generated.
the heat and sound energy are not destroyed however, but cannot be reused, they have become by-products or "wasted energy".
Chapter 3.4- energy can be transformed
when energy is changed from one to another, we say it has been transformed.
GENERATING electricity
wind generators use the wind to turn a turbine .
the kinetic energy of the wind is transferred to kinetic energy of the turbines.
the turbines then transform this energy into electrical energy.
energy can also be generated from wind, water, coal. Etc. The energy made from all this can be used to charge your phone, cook dinner, turn on a light. Etc.
remember, energy may take different shapes and forms before you can use it.
Chapter 3.6- energy efficiency can reduce energy consumption
techniques when constructing your house to make it energy effecient
Insulators: keep the house warm/cool whichever you please.
opaque windows: do not light come in
limiting the amount of windows facing the sun.
a veranda prevents the heat and light from the sun from shining on the walls. this is prevents the heat from being transferred to the walls, and then to the air inside.