To talk about electricity on Space Station Alpha, we have to use some technical words. Here are three words and a phrase you'll need to work with:

Volt: the word "volt" is used to describe an electrical force. Voltage is the word used to describe the total electrical force.

The power lines outside your house on the street carry 7500 volts of electrical force. Before it gets to your house, it goes through a transformer that "steps it down" so that your house receives either 120 volts or 240 volts of electrical force.

It is not necessary to have 7500 volts of electricity come into your house. This amount of electricity requires really big wires, too large to attach to the wall sockets in your house, very dangerous to work with, and carries more force than you need for any electrical appliance a house would need to make it work.

The Photovoltaic Arrays of Space Station Alpha create 160 volts of electrical power when they are in full sunlight. This is distributed throughout the Space Station. It is used, first, to recharge the batteries that will be needed when the Space Station is in the shadow of the sun. After that, the electricity powers all of the scientific experiments and the life support and communications equipment on the Space Station.

Amp: the word "amp" is used to describe the flow of electricity in terms of electrons through the wires. Amperage is how much electricity is actually flowing through a wire at any one time.

All the wires in your house will handle from 100 to 400 amps worth of flowing electrons, but these electrons are flowing through many wires and circuits and not all flowing at the same time. If you turn on everything electrical in your house, the meter outside that measures the voltage your house is using would be spinning like a top.

The force (voltage) coming into your house causes electrical flow (amperage) whenever a circuit is turned on. All circuits have switches and can be turned on and off for safety reasons, and to save electricity. Electrical flow is the number of negatively charged electrons flowing across a given point in any wire in your house at a given amount of time.

Let's pause, and consider that last idea. One (1) amp is used to describe the flow of 6,250,000,000,000,000,000 electrons across a given point in a wire in one second. (That's also called a coulomb.) That's a lot of electrons!

How does electricity happen? In a closed-circuit wire that is conducting electricity, (house wires are normally made of copper), the voltage, or positive force, causes electrons, which are negatively charged atomic particles swirling around on the outer energy shells of copper atoms, to jump away. They jump from their atomic orbits. For a split second the electrons are "free and flowing." Then each is attracted by another copper atom that is "downstream," so to speak. That "next" atom has also lost an electron and that loss gives it a positive electrical charge. Atoms, such as copper, iron, silver, and nickel atoms, hate not having enough electrons! That's why and how electrons jump from one atom to the next, and that's what electricity is.

Let's put this all in another way. If you switch on a light to read in bed, you open the circuit and permit the positive voltage force to repel electrons. They are now free to jump from atom to atom in the wires on the light side of the switch because the switch completed the circuit. The jumping-electron phenomenon extends through the wire and through the tungsten filament in the light. The tungsten is very thin, electrons in the filament are fewer, and the flow of electricity is resisted. (Resistance, by the way, is measured in Ohms. But we don't have to worry about Ohms in this unit.) The resistance in the tungsten "dams up the natural flow that is in the wire," causes the tungsten electrons to collide more frequently with the other atoms in the light's filament. The more frequent collisions cause heat. The heat energizes the tungsten atoms which send out light waves. The light waves, or light photons, hit the page of your book and are all absorbed by the page (which makes it look white)The white non-color (except where the print is) is perceived by the nerves in the back of the eye, the sensations are transmitted to your brain, and you "see." (Fortunately, the copper-jumping electrons in the wires don't cause heat or the wire would burn. Fortunately the nerves from your eyes don't overheat as well.)

A similar scenario can be used to describe a key piece of equipment on Space Station Alpha. The electrolysis machine, Elektron, which produces the oxygen for the Astronauts to breathe, is always turned on unless an astronaut turns it off in an emergency. It requires electrons flowing through water (instead of tungsten) to work. The switches connecting Elektron's circuit, are on so that electrons flow from the batteries, or directly from the photovoltaic array. Elektron is regulated by computers which require their own small flows of electricity to keep working. The atmospheric sensors signal the computers regarding the balance of gases in the atmosphere and thus regulate the flow of electrons to Elektron.

Watt: the word "watt" is used to describe the power it takes to make an appliance or light work. The voltage (force) times the amps (electrical flow) required to make a light light, a toaster toast, a refrigerator refrigerate, a hair dryer dry, or Elektron on the Space Station to electrolyze is that objects wattage. "Wattage" is the word used to describe electrical power required.

Your house may consume an average of up to 2000 Watts of power at any one time. Of course you could be using a lot more than this if you turn on some of the larger appliances in your house. Here are some items you may have in your house and the Watts of power they require to make them run. Some appliances have a range of Watts depending upon how they are made and the "jobs" you want them to do.

Light Bulb 25 - 200 watts
Can opener: 100 - 216 watts
Toaster: 800 - 1600 watts
Steam Iron: 1100 watts
Blender: 350 - 1000 watts
Computer: 125 - 200 watts
Computer Monitor 300 watts
Computer Printer 125 - 200 watts
Stereo Radio 420 watts
Stereo CD: 12 - 15 watts
Hair Dryer: 260 - 1500 watts
Popcorn Popper: 600 watts
Microwave Oven: 975 - 1575 watts
Refrigerator: 960 - 1200 watts
Water Heater: 4000 - 6000 watts
Clothes Dryer: 5600 - 9000 watts

The power systems on Space Station Alpha require 110 kW (kilowatts) (110,000 watts) of total power, about as much as 55 houses would typically, on average, use at any one time. Approximately 46 kW will be kept for research activities.

Your bedside, 100 watt incandescent light lights when the 120 volt force coming into your house pushes enough electrons through the 15 amp fuse (a normal fuse for a normal light circuit in the house) causing the filament in the light to heat up and make it glow. If everything else in you house is turned off, then there would be only 6.666 volts flowing through the meter.

We multiply Volts times Amps to get Watts. We divide amps by watts to get volts. And we divide Watts by Volts to get Amps.

Power Surge: a power surge is when an outside force such as lightning or a coronal mass ejection increases causes a sharp increase in the voltage flowing through the wires. Wires, fuses, and electrical appliances, whether in your home or in Space Station Alpha have what is called a capacity. If something causes more electricity to flow through a wire or electrical device or a safety fuse or breaker than is supposed to- it can cause a fire or a malfunctioning of a circuit!

In the case of a fire, if the electrical flow exceeds the electron-flow capacity of a wire, the heat may cause the wire to heat up and burn or light materials nearby. In your house, this causes electrical fire, a very dangerous fire that often starts inside a wall. In Space Station Alpha, a power surge could cause a fire in space.

More than likely, a power surge caused by a coronal mass ejection will disrupt the electrical generating capabilities of the photovoltaic arrays. This would mean that the arrays would not be able to function during the time the Space Station is orbiting in the Sun's light.

Another possibility on the Space Station is that a very low power surge may overload the delicate circuits in computers, some of which are etched onto silicon chips. This could cause the computer to malfunction. All of the Space Station's equipment is monitored and managed by computers.

Digging a Little Deeper

In your house there could be 240 volts of electrical service (That's the maximum domestic service allowed.) going through 400 amps worth of fuses (also, a maximum for a very modern house brimful of every appliance that money can buy) creating enough electrical power to turn on 96,000 watts (or 96 Kilowatts: 1000 Watts=1Kw) worth of lights, appliances, stereo equipment, etc.

The 400 amps of fuses are used to "break down" the voltage and "channel" it around the house in circuits.

Your stove is one circuit, so is your hot-water heater, clothes dryer, and central air-conditioning would have it's own circuit.

When electricians wire a house, or engineers wire the Space Station, they think something like this:

An electric stove requires 8,000 - 15,000 watts. Let's say your model at home requires 12,000 watts to "do its thing." The stove will probably be all alone on its own electrical circuit. You start your calculations with the 240 volt service to your house and divide it into the 12,000 watts to find out how much flowing electricity (amps) will be required by the stove to cook your food. The answer is 50 amps. Fifty amps is a lot of flowing electrons. To make sure that you are safe you would pick a wire and a fuse that could easily handle this amount of electrical flow without heating and causing a fire. To give you a safety margin, you would put in a 60 amp fuse for your electric stove AND you would us a heavy, #6 gauge copper wire that wouldn't burn up inside the walls with all those electrons flowing through it.

You should be able to answer this question. Why does an incandescent light burn out? Answer: It burns out when too many electrons flow across the filament. A filament gets old, and tired. It has been resisting electron flow for a long time. At some point it can't handle all those jumping electrons, the heat gets too great, and it melts and breaks. You have perhaps been near a light when it did this. There is often a bright light and then nothing.

Now you have enough information to understand the big picture:

At Home, power lines deliver 7500 volts of electrical power to the electrical pole outside your home. A transformer "steps down" the voltage to 120 or 240 volts. The breaker box with fuses or breakers, distributes the power to different circuits around the house depending upon what that circuit is designed to handle. Fuses are measured in amps and selected to meet the wattage needs of various appliances or circuits.

In Space Station Alpha (SSA) The photovoltaic cells (when they are receiving sunlight) and/or the batteries are delivering up to 160 volts of electrical power to Space Station Alpha. The power systems on SSA are regulated at 120 volts. All appliances must meet these requirements. All breakers, wires, and surge protectors are selected to ensure safe workings of all appliances under a wide range of conditions.