We need energy for pretty much everything, from keeping our bodies moving to keeping
the sun burning.
But where does it come from?
And /why/ do we need it?
What /is/ energy, anyway?
Hey there!
My name’s Alie
Energy is pretty complicated, but we’re going to figure it out together!
Physicists often describe energy as the ability to move something against a force, or the
ability to do work.
It can be stored energy, or released energy - but no matter what form it takes, energy
is a property of an object that can be transferred to other objects, or converted to a different
form.
Very importantly, energy can’t be created, or destroyed - it can only be transferred
from one thing to another.
This is called the law of conservation of energy.
There are a lot of different kinds of energy, too.
Kinetic energy is the energy of motion - the kinetic energy of a ball rolling is the effort
it took to push the ball across the floor.
Potential energy is the stored energy of an object relative to its environment.
If I’m holding a rock up in the air, the
rock has potential energy, because it’s being pulled on by gravity.
When I let go, it falls.
Elastic potential energy is energy that’s stored in an object that’s been bent or
stretched - like a rubber band that's being pulled.
The energy stored in the rubber band will transfer into the kinetic energy when I release it
One kind of potential energy that’s very useful to humans is the chemical energy that’s
stored in the bonds between atoms - our bodies use /this/ kind of energy!
When we talk about energy, we often talk about the electricity we use to power our homes
and gadgets.
See, electricity is a kind of energy too.
The energy in electricity comes from the movement of electrons, tiny, invisible pieces of atoms,
as they flow through a circuit.
Electrons carry electrical charge - tiny amounts of electrical energy.
When electrical energy is stored - like in a battery - it’s considered potential energy.
The energy is /there/, but it’s not doing anything.
Once you complete the circuit, it becomes electrical current energy - the electrons
can flow through the wire and power things along the way - like a lightbulb!
Electrical energy gets to our houses through power plants.
Fuel - like oil or coal - is burned to heat up water, making steam.
This steam is sent into a generator where it spins a special magnetic device and generates
electricity.
We can also get our energy from solar panels, which convert the bright sunlight directly
into electricity by gathering radiant energy.
Wind turbines
I thought it would be kinda funny if I like...had a fan on my face there? But I don't know if that's practical
Wind turbines, spinning in the wind, can be used to power the generator directly.
Wherever it comes from, the electricity can then be sent through power lines to homes
and businesses that are served by the plant.
That’s how you get the electricity to turn on the lights, cook your dinner, wash your
clothes, watch TV, and play on the computer!
After a long day of school or video games, you’re probably feeling pretty low on energy
yourself.
Turns out, we need energy too!
Living creatures get their fuel from food.
When you eat a cookie or a carrot, it starts the long process of digestion.
During digestion, the food is broken down into smaller parts - it goes from being a
cookie or carrot, to being crumbs, to being just molecules.
Eventually it’s broken down into glucose, the most basic kind of fuel for the body.
In a special structure called the mitochondria, the cells then do a chemical reaction using
oxygen to break apart glucose to create adenosine triphosphate - scientists just call it ATP
for short.
The ATP is sort of like a little battery in the cell - it stores energy in its chemical
bonds.
When the cells of the body need energy for something - like making our muscles contract
so we can run - it breaks apart the ATP molecules, using up the battery.
Our bodies can make ATP from other sources, too - like breaking down fat to help us survive
when we don’t have any food.
The human body is very good at finding ways to make energy!
So to review, there are a /lot/ of different kinds of energy - and they do lots of different
kinds of things!
Potential energy is energy that is stored, like a stretched out rubber band - and it can be transferred
into kinetic energy, the energy of motion, when you release it
Electrical energy powers our homes, and chemical energy powers our bodies.
One thing they all have in common is that different kinds of energy - and different
sources of energy - are important for helping power our world and our lives.
Thanks for watching this episode of Neuro Transmissions!
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Until our next transmission, I’m Alie Astrocyte - over and out.