Showing posts with label Electricity. Show all posts
Showing posts with label Electricity. Show all posts

Thursday, September 19, 2013

LEDs


We've now learned about diodes, photons and electroluminescence.

Wow!

Now let's learn about something called LEDs.

LED stands for light emitting diode.
Remember that a diode is a special thing you run electricity through.

When you put electricity through an LED, it shoots off photons,
which are tiny little light particles.

And the photons make the diode light up, using electroluminescence,
which means it gives off light when electricity goes through it.

LEDs can be made in just about every color, and unlike a light bulb they won't burn out!

led
(from: wikipedia - light-emitting diode)


Thursday, September 12, 2013

Electroluminescence


Electroluminescence is a pretty fancy sounding word,
but all it really means is a way that some things give off light
when you run electricity through them.

Electro - for electricity
luminescence - a fancy way to say light

Some of the best chemicals for making this kind of light are doped semiconductors,
which we learned before are just two kinds of chemicals mixed together.

When the electricity flows through them, the photons (which are tiny particles of light)
go shooting off of the chemicals and make it glow.
electroluminescence
(from: wikipedia - electroluminescence)

Thursday, September 5, 2013

Photons


When you turn on a light bulb or use your flashlight, it makes things brighter.

But does light actually have parts?
Is it made up of little bits, or is it just light?

It turns out light is actually made up of something called photons.

Photons have no mass meaning they don't weigh anything like an atom does,
but they do move around and they are tiny little particles!
photon
(from: wikipedia - photon)


Thursday, August 29, 2013

Diode


We've now learned about Doping Semiconductors, and how mixing some chemicals into
a semiconductor can turn it into a conductor.

Doped semiconductors can be used to make something called a diode.

A diode is something that you can put electricity through, but it only goes in one direction.
Kind of like pouring water down hill, it can't flow back up.

If you look on a circuit board you will see all sorts of diodes.
They are a very important part of how things like computers work!
diodes
(from: wikipedia - diode)


Thursday, August 22, 2013

Doping Semiconductors


We learned a while back that semiconductors are chemicals that do not conduct electricity very well.

Some scientists discovered a crazy thing, that if you mix up a semiconductor with another type of chemical,
then when you zap it with electricity it becomes a good conductor!

This is called doping or adding impurities into the semiconductor.

Remember we said silicon was a semiconductor.
The chemical arsenic can be added to silicon for doping.

silicon
(from: wikipedia - silicon)

arsenic
(from: wikipedia - arsenic)


Thursday, August 15, 2013

Anode and Cathode


We just learned that an electrode is pretty much just a wire
that has electricity going through it.

If you look closely on a battery, you should see a plus (+) and minus (-) sign.
This is for the positive (+) and negative (-) parts of the battery.

When you hook a wire up to both ends of the battery, that wire is an electrode.

The wire touching the negative (-) part of the battery is called the anode,
and the wire touching the positive (+) part of the battery is called the cathode.

Those words really just mean which way the electricity is flowing.

battery
(from: wikipedia - rechargable battery)

Electrons are negatively charged, and the electrical current
flows from the negative (-) anode to the positive (+) cathode.

Thursday, August 8, 2013

Electrodes


Remember that an electrical conductor is something that electricity goes through very well.

And a semiconductor is something that electricity goes through, but not very well.

Sometimes you want to connect a power source like a machine at a doctor's office,
to a semiconductor (like a person!) for some medical tests.

When you hook a good conducting wire up from a power source to a semiconductor,
that wire is called an electrode.

We use electrodes in all types of places from doctor's offices, to car batteries, to science labs.

eeg cap
(from: wikipedia - electroencephalography)


Thursday, August 1, 2013

Superconductor


We've learned that if something is kind of a good conductor but not really good,
we call it a semiconductor.

What about something that's a really super awesome conductor?

That's called a superconductor!

Superconductors don't work like good conductors or semiconductors do,
they're usually something normal like metal, but made really super freezing cold.

Not cold like when you go sledding in the snow, (about -10 degrees fahrenheit)
but so cold that you couldn't survive outside. (-300 degrees!).
Colder even than Antarctica, the coldest place in the world!

When the superconducting metal is that cold, it pushes out a magnetic field
that is so strong it can even push other magnets up off the ground!
superconductor
(from: wikipedia - superconductivity)


Thursday, July 25, 2013

Semiconductor


We've learned about how conductivity means how fast electricity goes through something,
and that metal is a good conductor, but rubber is a bad one, also known as a resistor.

What about things that are kind of good conductors?
We call those semiconductors.

One of the most common semiconductors out there is a chemical called silicon.
silicon
(from: wikipedia - semiconductor)

Thursday, July 18, 2013

Electrical Conductivity


Electrical conductivity sounds like a couple of big words,
but really it's not all that hard to understand.

We know about electricity from things like lightning, batteries or plugs.

Conductivity just means how easy or hard it is for electricity to go through something.

Things like metals are very conductive, but things like rubber or plastic are not very conductive.
This is why plugs and wires for your electronics are all made out of metal,
and the metal wires are usually wrapped in rubber because then the electricity can't get out!

electrical wiring
(from: wikipedia - electrical wiring)

Things like rubber that are not very conductive, can also be called resistive.

Thursday, July 11, 2013

Capacitors


We've now learned about how circuit boards have small things called resistors on them.

Another thing you may find on a circuit board is a capacitor.
It's kind of like a bucket that fills up with electricity, then dumps it out, over and over.

capacitor
(from: wikipedia - capacitor)

You have to be very careful with capacitors on circuit boards!

Even if you are looking at one that's not plugged in,
the capacitor can still be filled up with electricity and it could zap you!

Thursday, July 4, 2013

Resistors


Last week we learned about circuit boards how they are just many little
eletrical circuits made as small as possible on one little board.

If you look on those circuit boards, you will probably see something brown sticking out.
That is called a resistor.
resistor
(from: wikipedia - resistors)


Remember that we learned about resistance how it's like a small part of a tube
that the electricity is going through, and it slows down the flow?

Well that's exactly what the resistors on a circuit board do.

Thursday, June 27, 2013

Circuit board


We learned before about electrical circuits.

If you take apart something electronic like an alarm clock, computer or a radio,
you will see a colored board with a bunch of metal and plastic things sticking out of it.

This called a circuit board.
circuit board
(from: wikipedia - printed circuit board)

The lines that you see on the circuit board are made of metal that are like wires in a circuit,
laid out on the board as small as possible to save space and make electronics really tiny!

Thursday, March 21, 2013

Light bulbs

Inside a light bulb there are two wires that send electricity two a wire in the middle called the filament

This makes the filament glow super bright. It is typically made of a special metal called tungsten. (Sounds like tongues ten) light bulb
(From: Wikipedia - light bulb)

Thursday, March 14, 2013

Electrical Circuit


Now that we've learned about voltage, current and resistance,
we can try to understand an electrical circuit.

Remember what we've learned already by comparing electricity to water flowing through a pipe:
Voltage - The speed of the water flowing through
Current - How big around the pipe is
Resistance - A part where the pipe gets smaller and makes it tougher for water to get through

When people draw pictures to represent electrical circuits, they use special pictures and letters:
electrical circuit
(from: wikipedia - electrical circuit)

v with the circle and +- in it stands for voltage.
i with an arrow stands for current
R with the zig-zag lines stands for resistance

So if you think of it like a water hose, the faucet is starting at v and the voltage
is how much you've turned on the faucet. Just a drip or full blast?.

The current i is for how big around the hose is.
Is it just a regular garden hose, or a big fire truck hose?

The resistance R is if there are any kinks in the hose,
or if anything is stuck in the hose.

You can see that all those things together make the water come out of the end of the hose really fast or really slow!

Thursday, March 7, 2013

Resistance


Remember we said before that the three basic parts for most of the electricity that we see every day are:
Voltage, current, and resistance.

We can learn about electricity by comparing it to how water flows through a pipe.
We learned that voltage is like the speed that the water is going.
and that current is like the size of the pipe.

You can think of the Resistance as anything in the pipe that would slow down the water.

So if the pipe got smaller in the middle, that would make it so not as much water could flow through.
resistance
(from: wikipedia - hydraulic analogy)

Thursday, February 28, 2013

Electrical Current


Remember we said before that the three basic parts for most of the electricity that we see every day are:
Voltage, current, and resistance.

We can learn about electricity by comparing it to how water flows through a pipe.
And we learned that voltage is like the speed that the water is going.

The current, sometimes called amps, is like the size of the pipe.
Is it a very wide open pipe like a sewer pipe? Or a very small pipe like a straw?

The bigger the pipe, the more water can go through it, right?
That's the same for electricity, the larger the current, the more electricity is flowing.
pipe
(from: wikipedia - hydraulic analogy)

Thursday, February 21, 2013

Voltage


How does the electricity from the plug in the wall go through the wires,
and to the lamps, TVs and toys we use every day?

You can't see it with your eyes, but scientist have studied and discovered that
there are three basic parts for most of the electricity that we see every day:
Voltage, current, and resistance.

We'll take time to learn about these one at a time,
starting with voltage which is sometimes called potential difference.

It can be confusing to try and imagine the way electricity works when it's zapping through a wire or a plug,
so we try to compare it to a pipe filled with water, since that's something easy to picture in our imagination.

If you have a big pipe filled with water, you can think of the voltage
as the speed of the water going through, or the speed that it is being pushed through the pipe.
pipe
(from: wikipedia - hydraulic analogy)

Friday, November 23, 2012

Batteries - positive and negative


If you look close on a battery, you'll see a plus + for positive on one end and a minus - for negative on the other end.
batteries
(From: Wikipedia - battery)

When you connect a wire or a light bulb to the positive and negative ends of the battery,
the electricity will flow through the loop or circuit from the negative end to the positive end and light up the light bulb!

electrical circuit
(From: Wikipedia - electrical circuit, light bulb)

Thursday, September 20, 2012

Electrical Box


The electricity for your light bulbs, comes from wires in the ceiling and walls.
wires
(From: Wikipedia - electrical wiring)

Those wires go through the walls and end up in something called an electrical box, or breaker box.
In many homes it's found in the basement.
All the wires go into the electrical box, and there are switches like a light switch that can turn the electricity off for the whole house!
electrical box
(From: Wikipedia - circuit breaker panel)

The electricity comes into the electrical box from big wires that that go all the way back to the power company.