Please enable JavaScript.
Coggle requires JavaScript to display documents.
Energy changes and transfers (Energy chains (Energy can be transformed…
Energy
changes and transfers
"Energy is used whenever a force a makes something move"
Forms of energy
there is
Chemical energy
which is the energy stored in food or in an electric cell (a battery)
Electrical energy
that is due to electrical charges moving e.g electric current in a wire
Thermal energy
which is due to fast moving particles in hot items e.g warmth from fire goes to the people surrounding it, making them warm
Sound energy
which is energy carried by sound waves e,g sound waves from a speaker
Light energy
. Anything luminous gives out light energy
Kinetic energy
which is the energy in anything that is moving e.g a moving car
Nuclear energy
which is energy due to changes in the nuclei (plural of nucleus) of atoms e.g radio-active fuel in nuclear power station
Strain/elastic potential energy
which is energy stored in materials that have been bent of stretched e.g a rubber band stretched to the max
Gravitational potential energy
which is energy stored in materials that have been moved up so they can fall back down e.g a sledge at the top of the hill
there are many different forms of energy
Nothing can happen without energy
The standard unit of measuring energy is the
Joule
(J) one joule isn't that much and if the object we are measuring has a large number of joules we us
Kilojoules
(KJ)
one KJ=1000 J
Energy chains
Energy can be transformed from one form to another. These transformations of energy are called
Energy chains
In every energy chain the total amount of energy stays the same even though the type of energy is changing from one form to another
Scientists have measured many examples of these changes and have written
The Law of Conservation of Energy
which states
"Energy cannot be made or destroyed but it can change from one form to another"
which in basic terms means: The total amount of energy at the start=The total amount of energy at the end.
example of an energy chain:
electrical energy :arrow_right: Kettle :arrow_right: Thermal energy
Energy is not gone during an energy chain it just changes form
Almost all energy chains end in some form of Thermal Energy
Electricity
Electricity is a very helpful and widely used form of energy because
it is easy to control
it is easy to send from one place to another via wire
it doesn't pollute
Electricity can be transformed extremely easily into other forms of energy that can be useful
for proof see the energy chain example
Temperature
and energy
"
temperature
is a scale of numbers that we use to measure the amount of thermal energy that a material has"
Scientists measure temperature using what is called a thermometer
The three types of telling temperature
We have
Celsius or Centigrade
which has the freezing point of pure water at 0 degrees, the boiling point of pure water at 100 degrees and the human body temperature at 37 degrees and has absolute zero at -273 degrees
We have
Kelvin scale
which isn't really used now but has the freezing point of pure water at 273K,(in kelvin they don't use the small circle for degrees they just use a big "k") the boiling point of pure water at 373 degrees and the human body temperature at 310K and has absolute zero at 0K
We have
Fahrenheit
which has the freezing point of pure water at 32 degrees, the boiling point of pure water at 212 degrees and the human body temperature at 98.6 degrees and has absolute zero at -460 degrees
humans, like most mammals, are
Warm blooded
which means their body temperature stays the same even when their surroundings change temperature. the average human temperature is about 36.9 degrees C
Thermal energy: conductors and insulators
materials that allow thermal energy to pass through them are called
Thermal conductors
some of these things are better at being thermal conductors than others
you can tell it is a good Thermal conductor if it feels cold in your hand because it is taking the heat energy away from your hand
materials that
do not
allow thermal energy to pass through them are called
Thermal insulators
Thermal insulators are very useful when keeping heat in one place.
Metals are good conductors of thermal energy because of the way that their atoms are packed together
The atoms will vibrate because of the heat and will pass the vibrations onto the other atoms
Insulators do not have the structure that will allow them to do these vibrations so they cannot pass the vibrations on. Air is a great insulator because the particles are so far apart that they can pass energy on with ease
About half of the energy produced by power stations we cannot use. This unusable energy is called dissipated energy
This means that electrical energy is transferred to the kettle
:arrow_up:
:arrow_up:
This means that energy is transferred to the water as thermal energy
This is a thermometer :arrow_down:
