______________________________ wire
            /
           /
       [PENNY]
     ____________  towel
      {ALUMINUM}
       [PENNY]
     ____________  towel
      {ALUMINUM}
       [PENNY]
     ____________  towel
      {ALUMINUM}
       [PENNY]
     ____________  towel
      {ALUMINUM}
            \
             \_____________________________ wire

              *attach one wire here at the very bottom of the base
       _/_\_
      <     >    
      <     >      light bulb screw-in base
      <     >    
      <     > *attach the other wire here to the metal side
      / light\
     /  bulb  \
    /          \
    |          |
    |          |
    (          )
    ( _________)

1. How it works
2. Who invented it
3. Projects he can do as a class science project

A fluorescent bulb or lamp (as they are called in the industry) is a glass tube coated on the inside wall with a fluorescent material known as phosphor. The tube is filled with a gas and a small amount of mercury (in a liquid form) and is sealed. When a suitably high voltage (electric current) is applied between the electrodes at each end of the tube, the gas ionizes resulting in an electric current flowing through the tube (ionization is simply a group of atoms or molecules that have an electric charge). This also vaporizes the mercury. The current excites the vaporized mercury which returns back to liquid by the emission of ultra-violet (UV) radiation. Most of UV radiation is invisible but a funny thing happens when the UV radiation reaches the tube walls. The phosphor coating absorbs the UV, become excited (actually that is a scientific term) and re-emits it as visible light. It is the type of phosphor or coating that makes the fluorescent light either bright white, soft yellow or pink, depending on the type of light that is preferred.

The major difference between incandescent and fluorescent bulbs is energy efficiency. A 40-watt fluorescent lamp produces as much light as a 150-watt incandescent bulb. Even though the purchase price is higher, over its useful life, an 18-watt fluorescent light bulb saves 80 pounds of coal used to produce electricity. This means 250 pounds less of carbon dioxide released into the Earth's atmosphere. Because of this efficiency, fluorescent lamps produce less heat than incandescent bulbs. Fluorescent lamp technology has made significant advances over the past few years. Now there are new compact fluorescent lamps that can be used in regular home light fixtures.

The inventor of the fluorescent lamp... It seems to be a group effort in the labs however Albert Hall, in 1927, made improvements to the lamps so many consider him the "modern" inventor. The fluorescent lamps were introduced into the marketplace in 1938.

Regarding science projects...it would be up to your son to decide what he would like to do. It could be as simple as comparing energy uses between incandescent bulbs and fluorescent (as well as halogens, and other types of bulbs); doing a plant-growing experiment using fluorescents, natural daylighting, and other types of bulbs; experimenting why the same colors appear different in direct light, incandescent and fluorescent light...

San Diego Earth Times High-efficiency Fluorescent Lighting Cost Savings Calculator
and
How Things Work, by Louis A. Bloomfield

Good luck!

1. What experiment was Millikan known for?
a) The Flame Test


b) Oil drop


c) The Gold Foil Test


d) Burning pigs to figure the mole-mass ratio
2. Why is energy important to us?

The Professor Answers:
Pretty heavy-duty questions. Well, here goes.

I suppose that you're referring to Robert Andrew Millikan, a US physicist, who won the Nobel Prize in 1923 for his work on the elementary charge of electricity and on the photoelectric effect. Dr. Millikan first performed the "oil drop test" in 1909 making it the first direct and compelling measurement of the electric charge of a single electron. In other words, he figured out a straightforward method of measuring the very small electric charge that is present on many of the droplets in an oil mist. But you must know that since you asked me the question although I liked your burning pigs answer.

Now regarding why energy is important to us. There are lots of answers to that question. The obvious answer is that we need energy in the form of electricity (and you know what we use that for) and to drive vehicles and heat and cool our homes and schools. However, people got along without electricity and cars and TV and central heating and cooling for thousands of years before today. I think the more important reason we need energy is that we eat food grown by the sun (the life energy force) to fuel our bodies, producing energy so that we can walk, run, think and live. Without the sun and all the things that it provides, we would be non-existent. Why do you think energy is important?

The Professor Answers:
Actually, your sister is one smart person. She knows that leaving lights on when you don't need them is bogus and a total waste. It uses electricity, and then power companies have to build extra power plants to produce that extra electricity. That can cause more smog and more dirty air and more global warming and other "unfriendly-to-the-environment" things. Yuck!

Another thing. Wasting energy wastes money. Just one 100 watt incandescent light bulb burning for an hour uses a penny's worth of electricity. Now, a penny may not seem like much until you multiply it by all the lights around the house and all the hours that you forget to turn them off. Even leaving the TV on when nobody's watching can waste up to 6 cents an hour. Add all that up each month and it's enough to buy yourself something you've been bugging your parents for or maybe a nice present for your way-cool sister, who you should listen to more often.

Thanks for asking!

The Professor Answers:
Electricity is a kind of natural energy caused by the flow of tiny parts of atoms called electrons. All matter is made up of atoms, and all atoms have electrons in them. Some kinds of atoms have electrons that are loosely attached, and they can easily be made to move from one atom to another.

When electrons move among the atoms of matter, a current of electricity is created. This electric flow or "current" lights lamps and runs TV sets and many other appliances.

The Professor Answers:
A battery produces and stores up electrical energy. Electric current is generated when chemicals react with each other.

A flashlight battery is a good example. Inside a little can made of zinc is a carbon rod. Ammonium chloride (uh-MOE-nee-um KLOHR-ide) paste fills up the can. The ammonium chloride causes the carbon and zinc to react. Their electrons start moving around. When this happens, an electric current is produced. It flows between the carbon and the zinc.

A car battery uses two kinds of chemicals -- lead and lead peroxide (instead of carbon and zinc). These chemicals are in the form of solid plates. There is a sulfuric (sull- FYOOR-ick) acid mixture around the plates. The acid makes the plate materials react. While your car is running, it has a small device called a generator that recharges the battery so it can be used the next time you start up.

When all the chemical energy from the plates has changed to electric current, the battery is dead. Then an external battery charger can be used to reverse the chemical reaction and put more energy back into the battery. So, unlike a flashlight battery, which cannot be recharged, this battery can once again store up chemical energy. Now it can start the engine and run the lights again.

You might consider changing your flashlights' and toys' batteries to ones that can be recharged. That way you won't have to throw away old batteries and buy new ones. A rechargeable battery can be used again and again. This helps save energy, too!