Water Breakdown

You may know that water is also known as H₂O, with two hydrogen and one oxygen atoms. We think of water as being very stable, and not very likely to break down into hydrogen and oxygen. But with a little help from a battery, you can do just that!

What you'll need:
Small glass or clear plastic cup
Water
9-volt battery
2 pencil leads (actually a form of carbon called graphite)
2 short pieces of wire with the insulation stripped off the ends

4 alligator clips

Attach the clips to each end of a wire piece. Fill the glass with water and put the pencil lead electrodes in the water so that they do not touch each other. Clip one wire onto one electrode, and the other clip to the second lead. Attached the free ends to the terminals on top of the 9-volt battery. This gets a current flowing through the water. Watch carefully - what do you see happening?

After a minute or so, you will notice some bubbles of gas forming around each electrode. One of the electrodes will be generating about twice as much gas as the other. This is the electrode creating hydrogen; the other gas is oxygen!

This is an example of a process called electrolysis. As you know, water doesn't just break down like this normally. You have to put energy into the system, and in this case, the flowing electrons from the battery provide that energy. So electrons aren't just useful for powering your toys and other electronic gadgets - they can rip molecules apart, too!

A Battery of Batteries

There are many, many different kinds of batteries in use today. Here is a partial list:

• A dry cell is your basic non-rechargeable battery, which usually puts out about 1.5 volts. They are based on a combination of zinc and carbon. These must be disposed of when they are dead.
• Alkaline batteries contain zinc and manganese dioxide; the paste is potassium hydroxide, which is basic (another word for alkaline). You can get more power from an alkaline battery than from a dry cell, and the alkalines can be stored longer before use.
• Nicad (or nickel - cadmium) batteries are rechargeable. Some of them are made in the same sizes as standard dry cells or alkaline batteries, and can be sometimes used interchangeably. However, nicad batteries only produce 1.2 volts, and are not good replacements in all devices.
• Car batteries are lead-acid batteries, and they are obviously rechargeable. They are large and heavy, however, and can develop leaks of dangerous sulfuric acid.
• Lithium-ion batteries work differently from other batteries. In these, the moving charge carriers are not electrons at all, but rather, positively charged lithium ions. They are very lightweight and are less affected by low temperatures. Lithium-ion batteries are used in some electric cars.
• Many of the small "button cells" used in watches and calculators are silver oxide batteries.

See how many types of batteries you can find around your home!

Battery Power

Lots of modern electrical devices, like cell phones, calculators, computers and iPods are powered by batteries, and batteries are pretty amazing things. They're like a little container of electricity - lightweight (usually) and portable. When they're "empty", we either throw them away or recharge them. But what is inside a battery? How do they work?

Every battery actually holds a chemistry experiment! The first modern battery was created in 1800 CE by the Italian scientist Alessandro Volta (the "volt" is named after him). He realized that, if he stacked two different metals (copper and zinc in this case) separated by layers of cardboard soaked in salt water, electrons would start to flow through the whole pile, spontaneously generating an electrical current. Archaeologists may have discovered some even older batteries near Baghdad, Iraq, which date back to 200BCE.

Inside a battery, there are two metal electrodes surrounded by a sort of paste that lets the electrons flow. You might have noticed that most batteries are marked with a "+" (positive) and a "-" (negative) end. When the battery is being used, the negatively charged electrons flow from the negative end (called the cathode) to the positive end (the anode) - remember that opposites attract! Around and around they go, but eventually they run down, the electrons stop flowing, and you have a dead battery. Some batteries have to be thrown away when they die, but others can be recharged.

The next post will show you how you can make your own battery out of some things you probably have around the house. You'll also be able to see what effect varying the metals electrodes has on the voltage produced by the battery.

E-lemon-tricity

You can actually build your own battery with some items you may have around the house, starting with, of all things, a lemon!

What you'll need:

1 lemon

Small knife

Voltmeter

Metals for electrodes:

New, shiny penny (copper)

Steel paper clip (mostly iron)

Aluminum foil (1/2" x 1")
Galvanized nail (zinc-coated)

Roll the lemon on a table or other surface. Cut a slit in the wide middle part of the lemon to the penny, paper clip, or aluminum foil electrode. The nail can be just pushed in. Place two electrodes in the lemon about one inch apart. Touch one lead from the voltmeter to one electrode; touch the other lead to the second electrode. Read the voltage. Change one of the electrodes and measure the voltage again. Check these combinations: penny-paper clip; penny-foil; penny-nail; paper clip-foil; paper clip-nail; foil-nail. Are the voltages the same or different?

You'll find that the voltage changes depending on the metals used. The largest voltage probably came from the penny-nail (copper-zinc) combination. Now, the voltage coming from this battery isn't very high, and it can't be used to power any devices like a flashlight, calculator, or iPod. You can actually connect a couple of lemon batteries together to light up an LED (small lightbulb), but this requires some additional equipment. If you are interested in trying this, check out this video.

Farads, and Henries, and Ohms... Oh, My!

If you look at an electrical circuit board, you will notice that it has a lot of little components, all connected in a very complex way. The art and science of designing electronics is too complicated to go into here, but we can talk about some of the little components, what they look like, and what they do.

Capacitors are devices that store up electrical charge. Then the charge can be released all at once. The appearance of capacitors varies a lot, but many of them look like small ceramic beads. The unit associated with a capacitor is a farad.

Inductors are little coils of wire. They generate magnetic fields, and are used to make motors. The strength of an inductor is measured in a unit called a henry.

Resistors are small cylinders that often have stripes on them. The stripe colors indicate the strength of the resistor, which is given in ohms. Resistors will slow down the flow of electrons, called the current.

Transistors often look like little cylinders, tabs, or metal disks. They are often used to make increase the strength of an electrical signal or as a switch.

Integrated circuits contain lots and lots of other tiny electrical components, and they can do more complicated jobs than the other devices listed above. IC's, as they are often called, are usually black squares or rectangles, with a bunch of little metal legs.

Here's a computer simulation that will let you play around with constructing electrical circuits without having to find all the components, and without the risk of getting an electrical shock! See if you can create a circuit that will light the bulb!

Round and Round

Let's move on to electrical circuits, in which electrons move around and around in a circle, doing all kinds of useful things in the process. This is the kinds of electricity involved when you use a device that is powered by batteries or by plugging it into the wall. Look around you. How many such devices do you see?

The important thing about electrical circuits is that the circle cannot be broken. There must be an intact path for the electrons to flow through. Here's a fun game you can play that will give you a basic understanding of the way that electrical circuits work. You should note that this game was developed in Great Britain, and it uses some different words. For example, it calls a flashlight a "torch", and the power from electrical wall plugs is called the "mains". Other than that, you should be able to understand the game.

Static in the Sky

If you get zapped by static electricity, you sometimes see a little spark. What's the biggest spark you have ever seen? Here's a hint - you often see it in the summer during a storm. That's right - lightning is a giant static electric spark. What causes lightning?

It's those positive and negative charges again. The water molecules in rain, ice or snow bump into one another and build up negative charges on the bottom surface of the clouds, just like you built up negative charges by rubbing a balloon on your head. This makes things on the ground positive, and eventually electricity will flow between the cloud and the ground, making a very impressive lightning bolt. It travels to the ground at 140,000 miles per hour (220,000 km per hour), and the air around the bolt becomes several times hotter than the surface of the sun, at 54,000^oF (30,000^oC). All this energy makes the air molecules vibrate so much that they make noise - thunder! Lightning is beautiful, but very dangerous. If you are outside when at lightning storm starts, you should immediately go indoors!

Waterbender

You can use static electricity to bend water to your will!

What you'll need:
Plastic comb or balloon
Faucet

Turn the faucet on so that only a tiny stream of water comes out (1/16 inch, or 1-2 mm). Run the comb through dry hair or blow up and rub the balloon on your hair. This will build up a static charge. Position the comb or balloon near the water and you will see the stream bend away from the charge. Who knew moving water around was so easy?

1,001 Uses for Dryer Sheets

OK, I won't really give you 1,001 uses for dryer sheets, but that heading sure got your attention, didn't it? Actually, the antistatic property of these sheets make them useful for a lot of purposes. Many of these even work with previously used sheets, so you can recycle them! Here are some of them:

• If you have flyaway hair, lightly rub a sheet on your hair, and it will lay flat. Or, you can rub the sheet on your brush or comb.
• If your clothes are sticking to you, rub the sheet on the inside of the fabric. No more static cling!
• Dusty television and computer screens are easily cleaned with dryer sheets.
• Got an iron with gunk on the bottom? Set the iron on low, and rub with a sheet.
• If you have pots and pans with burnt-on food, add a little water and a dryer sheet. They will be much easier to clean after they soak overnight.
• If you're trying to sew, and the thread keeps getting tangled, wrap a sheet around the thread and slide over the length.
• Dryer sheets will remove soap scum from glass shower doors.
• You can remove pet hair from clothes and furniture with a dryer sheet.
• Dryer sheets are great for picking up messes like sawdust and talcum powder.
• Rubbing dryer sheets on surfaces like window blinds help reduce dust buildup.
• Latex paint will come off paint brushes more readily if the brushes are first soaked in water with a dryer sheet.

That's eleven other antistatic uses! Not bad for a simple dryer sheet!

Opposites Attract

So why did the balloon grab hold of your hair and lift it into the air? And why did it pick up the tissue pieces? And what's in that dryer sheet?

When you rubbed the balloon on your hair, some of the electrons in your hair jumped over to the balloon. Since electrons are negative, that made the balloon negative. And since your hair was then missing some negative stuff, it became positive. Have you ever heard the expression "opposites attract"? Well, that applies to positive and negative, too! So, the negative balloon and your positive hair wanted to stick together. But since your hairs were all positively charged, they tried to get far apart from one another, and gave you that wild and crazy look! The tissue pieces are neutral, neither positive nor negative. They were also attracted to the balloon because the charges are different.

The antistatic dryer sheet contains a chemical that easily gives up positive charges. When you rubbed the balloon with the sheet, the positive charges moved to the balloon and neutralized all the negatives already there. So you ended up with a neutral balloon that didn't do anything fun!

A Really Bad Hair Day

Electricity is a force that is created by electrons, tiny bits of negatively charged matter that are usually found in atoms and molecules. However, sometimes the electrons break free and create either current electricity or static electricity.

Current electricity is the kind we usually thing of, in which we get the power from a battery or from plugging into a wall outlet. Electrons flow from one place to another, like a river. We'll explore current electricity more later this month.

In static electricity, the electrons have no where to go, and they just pile up. When they are provided a path to flow through, they rush over all at once. If you have ever walked across a carpet floor, then gotten a nasty shock when you touched something metal, you've had a taste of static electricity. The girls in the photo at left are experiencing static electricity created by a van der Graaf generator (the silver dome in the background).

Here's a fast, simple experiment you can try that will demonstrate some basic ideas about static electricity.

What You'll Need:
Balloon
Facial tissue, torn into small pieces
Antistatic dryer sheet

Blow up the balloon and tie the end. Rub the balloon all over your head (unless you're bald, then find someone with hair!). Slowly pull the balloon away from your head. What happens to your hair? Do the individual hairs on your head stick together or fly away from one another? Place the balloon near the facial tissue bits. Do they react? Now rub the dryer sheet all over the balloon, and try to pick up your hair and the tissue pieces. What happens?

Science in the News

Electricity is very much in the news these days in northern New Jersey, where I live and work. A freak early snowstorm over the weekend dumped over a foot in some places, resulting in widespread electrical power outages. Many people, including a lot of my friends and coworkers, still haven't had their power restored, and some of them may need to wait several more days. This problem covers a wide area - over 1 million people are still power-less in New England.

Why did this happen? Twelve inches of snow during the winter doesn't usually cause such havoc! The answer is, of course, that many, many tree branches came crashing down because of the weight of the snow. During winter, the trees have no leaves, and little snow sticks to the bare branches. But in October, the trees still have most of their leaves, which catch the snow. Falling branches pulled down power lines, causing the electricity to go out. It's taking a long time to remove all these branches and get the power turned back on.

Power outage are really inconvenient, but people can make them dangerous. If you see a dangling power line, you should never, ever touch it. Call the electric utility, and they will send a crew to fix it. Using gas stoves, space heaters, or faulty generators to keep warm can lead to dangerous levels of carbon monoxide, a poisonous gas. So, if you're stuck in a power outage, be smart and stay safe!

Zap!

This month, we'll be exploring the shocking truth about electricity - that almost-magical force that powers so many of the things in our life. What is electricity? Where does it come from? You'll learn how to make a battery, how to use batteries to split water into its elements, and more!