THE SCIENCE OF

LASERS, LIGHT & ENERGY

INTRODUCTION

In this section we are going to delve into the scientific and technological parts of LAZER VAUDEVILLE which separate the show from old-fashioned vaudeville. We will provide the diving board from which students and teachers alike may plunge into a world of fascinating science projects. We’ll explore how lasers work and what makes things glow in the dark. We’ll experiment with regular light as well as blacklight. We’ll find out why the ozone layer protects us from the sun’s radiation and what that has to do with microwave cooking. We’ll even show you how radio waves help us perform the LAZER VAUDEVILLE show!

LASERS

Some lasers are very tiny but some can be huge. The beams can also be incredibly small and precise. Some beams are so thin they could be used to drill 200 holes in something the size of the lead in your pencil. Lasers can cut through diamonds, the hardest substance known to humans. In 1969 astronauts placed a laser-reflecting mirror on the moon and scientists sent a laser beam to the moon and back, in order to measure the distance to the moon. It’s 238,000 miles each way!

There are many different types of lasers. In everyday life we see lasers at the supermarket check-out counter. They are used to scan the bar code on groceries. Lasers also read the digital information on music and computer compact discs. Lasers are small and precise enough to do eye surgery, and big and powerful enough to cut and weld metal.

So how do lasers actually work?

The lasers you see in Lazer Vaudeville are programmed to make up a laser show. A laser show has three main elements:

1). The laser.

2). The graphic imaging system that turns the beam of laser light into all the spectacular images.

3). The surface - screen, fog, or ceiling, which the laser image shows up against.

There are three main parts to a laser:

1). An energy source - electricity.

2). A material - helium/neon gases.

3). A container - the laser tube itself. 

Electricity: If you’ve ever used a toy train set then you’ve had some contact with an electrical power transformer. On a toy train set or car set this is the small heavy box that the electricity runs in and out of. This transformer takes normal wall outlet electricity and changes it or transforms it to a lesser voltage that is safer for small children. Lasers also use a power transformer but it does the exact opposite of a train set transformer. It makes the electricity a higher voltage and therefore more dangerous. Obviously, we’re very careful with the transformers we use in LAZER VAUDEVILLE. 

Helium/neon gases: We send the electricity into helium and neon gases for the second step. Helium and neon are both gases we see in our everyday lives. These gases are not liquid like the gas used in cars. Rather they are gases similar to the oxygen in the air we breathe. In fact, when helium inflates a balloon the helium is lighter than the air around the balloon, so the balloon floats upward. We see neon gas in action almost every day in neon signs. Neon gas is the gas inside the glass tubes of a neon sign. We combine both helium and neon gases inside our laser tube. 

The laser tube: The helium and neon gases are placed in a very pure form inside the laser tube. The inside of the laser tube is a highly reflective, mirror-like surface, everywhere except for a tiny area at the end of the laser tube where the beam comes out.

When the high voltage electricity gets sent into the helium gas it makes the helium atoms bounce into each other like rush-hour traffic in Chicago. When they do this the neon atoms all get excited at the same time and go into a state of high energy. They radiate (give off) this energy as light. When they radiate this light they are influenced by each other’s light, and produce more light. This is called stimulated emission. They all radiate in the same direction, down the laser tube to the tiny hole at the end.

The tiny hole is covered on the inside by a mirror just like the rest of the laser. But the mirror at this point is not quite as reflective. It is more like a two-way mirror that lets some of the light through but not all of it.

Experiment: How lasers get out of the laser tube.

What you need: 1 flashlight of the "mag-lite" variety, 1 two-way mirror available from some hardware stores or Edmund Scientific listed in "SOURCES" at the back of this study guide.

What to do: Shine the light through each side of the two-way mirror. The part that is 100% reflective is like the inside of most of the laser tube, however the other side lets some of the flashlight’s light through.

What it means: The side that lets some of the light through is like the hole in the laser tube that lets the laser light through. 

****************************** 

Experiment: Create laser patterns.

What you need: 1 flashlight, 2 mirrors, each about 1 foot square, available in local hardware stores.

What to do: Mount the flashlight or laser pointer on the edge of a table so that it is level. Use tape. Have 1 student place the first mirror directly in front of the flashlight so that it reflects directly back to the flashlight. Now slowly tilt the mirror up so that the reflection hits the ceiling. Have a second student place mirror #2 directly over mirror #1 so that it reflects the light directly back down. Tilt mirror #2 up slowly until the reflection goes to the wall. Move mirror # 1 slowly, and then more quickly and watch the reflection on the wall do different things. Then keep mirror #1 still and move mirror #2. Then move both mirrors at different speeds and see what happens with the reflections.

What it means: This is an exact simulation of the way the lasers, the laser mirrors, and the computer work together to create the laser patterns seen in a LAZER VAUDEVILLE show.

How are the laser images made?

The laser beam hits one mirror and this mirror swivels up and down in the vertical plane known as the Y axis. Next the laser hits a second mirror which swivels side to side in the horizontal plane known as the X axis. When the two combine you can get diagonal lines, circles, triangles, and spectacular spiro-graphic images. These patterns change depending on which mirror is moving faster or slower and how far side to side or up and down the mirror is moving. These two mirrors are each controlled by a computer.

MORE ABOUT LASERS !

How are other types of lasers made?

The biggest difference in lasers are the amounts and power of electricity used, and the material the electricity stimulates. Some different materials lasers are made from are:  

Gas lasers: Helium & neon lasers are not the only gases used in lasers. Argon, krypton and carbon dioxide are some other gases commonly used in lasers. The type of gas determines the color of the laser. Helium results in red, argon in green. 

Carbon dioxide lasers produce infrared light that cannot be seen by the naked eye. These lasers are some of the most efficient lasers in the world, converting as much as 95% of their energy into laser light. If scientists are ever able to set up solar energy collection stations in outer space and then beam the energy to earth, this is the type of laser they will use. 

Solid state lasers: These use a solid material usually made of crystals or glass. The most common crystals used contain small amounts of neodymium . This is how the world’s largest and most powerful laser is made. It is about as long as a football field, and it lives at the Lawrence Livermore National Laboratory in Livermore, CA. Its light can go up to 100 trillion watts of power. 

Semiconductor lasers: These have two solid materials and the stimulated emission occurs where they meet. These are the smallest lasers in the world. Some semiconductor lasers are in fact only visible under a microscope. Some metals used in these lasers are indium, gallium, and arsenic. The small size of these lasers makes them perfect for CD players, pen lasers, and other miniature devices. 

Dye lasers: These lasers dissolve dye in alcohol to form the material. The best thing about this type of laser is that it can produce different colors by tuning them the way you tune a radio.

When were lasers invented and how did they get their name? 

Stimulated emission was first thought of by Albert Einstein in 1916, but the first laser was not built until 1960 by the American Theodore H. Maiman. Laser is a special type of word called an acronym. An acronym is a word made up of the first letters of several different words. LASER stands for: Light Amplification through the Stimulated Emission of Radiation. 

In the Lazer Vaudeville show, we spell laser with a "z" for that show-biz effect.

RADIATION 

Lasers do have radiation, but at very safe levels, and the radiation they do have is confined inside of the laser tube where the stimulated emission occurs. The sun puts out radiation, the rocks and the soil of the earth are also putting out radiation. In fact all light is radiation and if none of the radiation from the sun reached us at all, the earth would get cold and freeze. X-rays that doctors and dentists use to see your bones and teeth also use radiation. Small amounts of radiation are natural, but large amounts can be harmful. All electromagnetic waves are radiation, but only the shorter waves of gamma rays are harmful to humans.

LIGHT 

Light is energy! The sun produces heat and light energy on the earth. The energy of light is known as radiant energy. There are many kinds of radiant energy. In fact there is an entire spectrum of radiant energy. On the short wave end of the spectrum there are gamma-rays, x-rays, and ultraviolet rays. In the middle there is visible light, the light we as humans can actually see. On the long wave end of the spectrum there are infrared waves, micro-waves, and radio waves.

The technical term for these rays, waves, and visible light is electromagnetic waves. In 1864 the Scottish physicist James Clerk Maxwell predicted that electromagnetic waves existed but this was not proven for another 20 years. In the 1880’s, the German physicist Heinrich R. Hertz proved the existence of electromagnetic waves. Humans can only see visible light, we cannot see the low end of gamma, x, or ultraviolet rays, nor can we see the high end of infrared, micro, or radio waves. Gamma rays have the shortest wavelengths and radio waves have the longest, sometimes as long as several miles.

In 1666 the English scientist Sir Isaac Newton discovered that white light is made up of all visible colors. When white light passes through a special piece of glass called a prism it is broken up into all the colors of visible light. 

Experiment: Split a sunbeam.

What you need: A prism, white paper, a sunny day.

What to do: Go outside in the sun. Hold the prism up to the sun with the white paper behind it. The sun’s rays will split and a rainbow of colors will shine on the white paper. Now do the same thing indoors with a regular light bulb. Now try the same thing with a fluorescent light.

What it means: Light waves from the sun are bent and broken down into their full spectrum of colors based on their vibrations and wavelengths. Light waves from an indoor or fluorescent light bulb do not have a full range of light the way the sun does. Some of the colors from the prism are not as bright. This illustrates Sir Isaac Newton’s discovery.

Experiment: Bending light.

What you need: A bowl, a quarter, a pitcher full of water, a friend.

What to do: Place the bowl on a table and the quarter in the bottom of the empty bowl. Then step away from the bowl until you cannot see the coin. Have your friend pour water into the bowl. Magically the coin will appear.

What it means: This shows that light waves are bent as they pass through water. 

How fast does light travel?

Light travels at the speed of 186,282 miles per second. In the metric system that’s 299,792 kilometers per second. Light travels fast enough to circle the Earth 7 ½ times in one second. In 1862 the French physicist Foucault made the first semi-accurate measurement of the speed of light. He came up with 298,000 kilometers per second. 

MORE ABOUT LIGHT !

Light travels in waves similar to waves in an ocean. The first scientist to mention this theory was the Dutch physicist Christian Huygens in the mid 1600’s. This was later proven in the early 1800’s by the English physicist Thomas Young.

Early physicists thought that light waves had to travel on something, just as waves in an ocean travel on water. They called this invisible substance the ether. But no one could measure the ether or even prove that it was there. In 1887 experiments by the American physicists Albert A. Michelson and Edward Morley helped prove the ether theory false. A theory is an idea that no one has yet proven true or false.

How do light waves travel?

Light waves are electromagnetic waves. But light waves are just a small section of all electromagnetic waves. Light waves are just the ones we can see with the naked eye. They are actually a combination of two kinds of waves, electric waves and magnetic waves. These waves are on two different planes or surfaces. Imagine the electric waves going up and down the same way a roller coaster goes up and down; this is the vertical plane. The magnetic waves move just like a snake in the grass winding from side to side; this is the horizontal plane. These two waves happen at the same time to create electromagnetic waves and light waves. The distance between the top of each wave is called the wavelength. The size of the wavelength determines the color of the light. Longer wavelengths are closer to the red end of visible light, and shorter wavelengths are closer to the purple or violet end of the visible light spectrum. (For a color diagram of the visible light spectrum, see a science text book.)

How is light made?

All light comes from atoms. When an atom gains extra energy it is said to be an "excited atom". One way it can get rid of this energy is by giving off light. The wavelength of light is measured in nanometers. One billion nanometers = 1 meter. Meters, centimeters, millimeters, and kilometers are part of the metric system. This is the measurement the rest of the world uses instead of inches, feet, yards, and miles. Visible light waves start at about 400 nanometers, and go up to about 700 nanometers.

Regular light from the sun or a light bulb spreads in all directions and is called incoherent light; the wave lengths of this type of light are constantly changing. Laser light goes in one direction in a very tight beam and is called coherent light; the wave lengths of this type of light are exactly the same. The main difference between regular light and laser light is that the atoms inside the laser create the light through stimulated emission.

Experiment: Make a fluorescent bulb glow without plugging it in. *Teacher/Parental Supervision Recommended*

What you need: A long fluorescent bulb, a soft wool cloth. A dark room.

What to do: Go into the dark room and rub the bulb with the wool. Watch as the bulb glows where it is touched by the wool.

What it means: Electrons are pulled from the glass by the wool. This creates a positive charge thus drawing electrons from inside the bulb to the glass, through the mercury vapor inside the bulb. This creates the light.

RADIO WAVES 

Lazer Vaudeville uses radio waves in two very important ways. When you hear a performer talking they are using a cordless microphone . This would not be possible without radio waves. This microphone is very small, about the size of the cap to a ball point pen. The performer clips the microphone onto his or her shirt, and the sound of the voice is transformed into radio waves and sent to the sound system in a fraction of a second. Having a cordless microphone allows the performer to move around the stage, juggle, and do other things without getting tangled up in cable.

Behind the scenes we also use cordless headsets to tell the lighting technician when to turn the lights on and off. We also use the headsets to tell the stage hands when to open and close a curtain or move a piece of scenery. These headsets have microphones as well as ear pieces. 

Radio waves are also electromagnetic waves. They are the longest of all the known electromagnetic waves. Both television and radio use the section of electromagnetic waves known as radio waves to broadcast their signals to their listeners and viewers.

The Federal Communications Commission (FCC) assigns the specific frequencies for all radio and television signals in the United States. In Canada the Canadian Radio-Television and Telecommunications Commission assigns the frequencies for all radio and TV signals. 

How radio works:

Radio stations turn sound into radio waves and then broadcast them from a transmitter antenna. The radio waves go through the air in all directions and are then received by a radio. The radio then turns the radio waves into sound waves. The stronger the transmitter at the radio station, the farther the radio waves travel.

Each radio station is on a different channel or frequency which keeps them from interfering with each other’s broadcasts. There are two types of radio station, amplitude modulation (AM) and frequency modulation (FM).

MORE ABOUT RADIO !

Guglielmo Marconi of Italy sent the first radio signals in 1895. He was able to send telegraph code signals more than one mile. In 1901 Marconi’s radio equipment sent code signals across the Atlantic Ocean from England to Newfoundland. The Canadian Reginald A. Fessenden was the first person to broadcast human speech over a radio in 1906. Experimental radio broadcasts began in 1910 with Lee De Forest broadcasting a program from the Metropolitan Opera House in New York City. Radio station WWJ in Detroit, Michigan, began the first commercial broadcasts on August 20, 1920. However KDKA in Pittsburgh, Pennsylvania grew out of an experimental station started in 1916. KDKA broadcast the election results of the Presidential elections on Nov. 2, 1920. The first license the federal government issued to a station was on Sept. 15, 1921 to WBZ in Springfield, Massachusetts.

AM and FM RADIO

Each radio station is on a different channel or frequency which keeps it from interfering with other stations broadcasts. There are two types of radio stations, Amplitude Modulation (AM) and Frequency Modulation (FM). The strongest AM stations may have 50,000 watts of power and can be heard as far as 2,000 miles away. The strongest FM stations may have 100,000 watts of power, but can only be heard 70 miles away. Why is there a difference? FM radio signals only go as far as the line of sight, in other words as far as the horizon. This is why most FM antennas are located on top of a hill, mountain or very tall building. AM radio signals follow the ground when they spread out but they also go up into the sky. When AM signals reach a layer of the atmosphere called the ionosphere, they bounce back down to earth, then they bounce back to the ionosphere, then back down to earth, and so on until the signals become too weak to be heard. These AM signals go further at night when the sky is especially clear. AM signals get more interference from static than FM signals, therefore FM stations often have a better sound quality.

Frequency is measured in units called hertz (vibrations per second). One kilohertz = 1,000 hertz. One megahertz = 1,000,000 hertz. AM stations broadcast from 535 to 1,705 kilohertz. FM stations broadcast from 88 to 108 megahertz.

BLACKLIGHT

When you come to see a Lazer Vaudeville performance, you will see some segments performed in "blacklight", or ultraviolet light. If you go to the theatre you’ll see Alfonzo, the seven-foot tall, fire-breathing dragon; if we come to your school, you will see the "neon cowboy" spin ropes. To the human eye, both characters appear to glow in the dark.

In reality, neither the dragon nor the cowboy glows by himself. They are wearing clothes coated with a special fluorescent material that gives off visible light when you shine ultraviolet light on it. The ultraviolet light comes from four-foot, tube-shaped bulbs mounted on the edge of the stage like footlights. These bulbs are coated with black paint to prevent any visible light from coming out of them, and so they are called blacklight bulbs. 

Experiment: Make magic markers appear differently.

What you need: Regular & "neon" style magic markers, regular light bulb, blacklight bulb, paper.

What to do: Assemble two sets of magic markers: #1 the regular colors of red, green, blue, & #2 the bright, "day-glo" highlighter markers. Write the words "normal" and "fluorescent" with each of these markers and see which is brightest. Look at the words under three types of lighting: normal round incandescent light bulbs, long white tube - fluorescent lights, and a blacklight bulb or a tube.

What it means: This illustrates the extra amount of energy the fluorescent markers absorb. You may notice that a blacklight bulb or tube, will make the highlighters glow the best. This is how we get the dragon, cowboy, and some of the juggling props to glow. The blacklight is made with very dark glass, in fact it looks black when it is turned off. That’s why it is called blacklight. That very dark glass filters out all the other light so only the ultraviolet light illuminates the fluorescent highlighters. 

Q. Who first discovered fluorescence?

1. It was first explained in 1852 by the British scientist Sir George Stokes. He was a special kind of scientist called a physicist. Physicists study the physical properties of our world. They work on problems as diverse as the way an apple falls from a tree to the way stars and planets move through the sky. An important part of physics involves the study of light: how it travels through space and how it is perceived by the human eye. Sir George Stokes named this special kind of light fluorescence.

Phosphorescence occurs when something glows in the dark of its own accord long after the lights have been turned off. Some stores sell toys or stick-ons that glow in the dark; these are phosphorescent. Lazer Vaudeville uses special tape that glows in the dark. We put this tape on stage in special patterns so that when the lights go out we can tell where we are and where we need to go. It’s like a map that we make in each theatre we perform in, and this map is phosphorescent. You can order glow tape from Grand Stage Theatrical Lighting Co. in Chicago, IL. See "SOURCES" at the end of this study guide. Ever wondered what makes fireflies glow? It’s a process called bioluminescence, which also occurs in certain species of deep sea fish. 

Q. Why does fluorescent material glow in the blacklight?

A. Fluorescent material glows in the blacklight because it absorbs or soaks up ultraviolet waves and reflects it as visible light. This happens incredibly fast. Sometimes the fluorescent material only keeps (retains) the energy for one trillionth of a second; this is still fast enough to make the fabric glow to the human eye.

ULTRAVIOLET LIGHT 

Ultraviolet light is put out by two sources we are all familiar with:

1. The sun.
2. The fluorescent blacklight tubes we use to perform LAZER VAUDEVILLE. 

Ultraviolet light can be both harmful and helpful. We need some of the sun’s ultraviolet light for plants to grow. If there were no ultraviolet light from the sun, nothing would grow; it would be deep winter all the time. Great if you like skiing. Hospitals use ultraviolet light to kill bad bacteria and viruses, and to sterilize the operating rooms. Ultraviolet light can be used to treat some skin diseases. It also produces vitamin D in the human body.

Too much ultraviolet light can cause sunburn and way too much can cause skin cancer. The ultraviolet light from blacklights or from white fluorescent tubes is so low that there is no danger from exposure to the skin or eyes. The sun is actually the largest source of ultraviolet light we have in our lives. One very important thing protects us from too much of the sun’s ultraviolet light: the ozone layer. 

THE OZONE LAYER

The ozone layer is found in the upper atmosphere between 9 and 11 miles above the earth’s surface. This ozone layer shields us from 95% to 99% of the sun’s ultraviolet light. In the 1970’s scientists discovered that a human-made chemical compound called chlorofluorocarbons (CFC’s) were gradually destroying the ozone layer. People used to use these CFC’s in aerosol cans and air-conditioning systems. In 1978 the United States banned CFC’s in aerosol cans and by 1995 most countries had stopped making them—good news for the ozone layer and for life on earth.

Ozone in the upper atmosphere is very good since it protects us from the sun’s ultraviolet rays. Down here on the earth’s surface, however, it contributes to pollution. It is part of what makes up smog. Such ozone can damage rubber, plastic, plant and animal life. Ozone was discovered in 1840 by the German chemist Christian Frederich Schonbein.

Scientists have discovered ozone holes over both Antarctica (The South Pole ) and the Arctic (The North Pole). These holes are found in the winter of Antarctica (June to September), and in the winter of the Arctic (December-February). The ozone holes repair themselves during the summer. Ozone is actually a form of oxygen. Oxygen molecules have two oxygen atoms. Ozone molecules have three oxygen atoms.

THE SUBSTANCE OF THE UNIVERSE 

Have you ever wondered what the smallest thing in the universe is? Have you ever wondered how small a grain of sand or a piece of dust can really get? Well, so have many scientists around the world, and here is what they have come up with. 

There are actually two smallest things in the universe and they are called electrons and quarks. But these are just the building blocks for bigger and better things. Quarks combine to create more complicated entities. Some quarks combine to make protons, and some quarks combine to make neutrons.

To get an idea of how an atom is put together, picture an egg. Now imagine that the egg is scrambled inside its shell. The protons are the yoke, the neutrons are the egg white, and both are mixed together inside the egg. But what is the eggshell? The eggshell is make up of those other extremely tiny particles called electrons. The electrons circle around the protons and neutrons, just as the eggshell surrounds the egg yolk. The whole thing, including the protons, neutrons and electrons, is called an atom. The very center of the atom, the part that is made up of protons and electrons, is called the nucleus.

Some of the atoms have more electrons and some atoms have fewer. Some atoms have more protons than neutrons and some have fewer. That’s what makes some atoms oxygen atoms, some helium atoms, and some nitrogen atoms.  

When a bunch of different atoms get together they form a molecule. For instance, if you put two hydrogen atoms together with one oxygen atom, you get a water molecule. If you put a bunch of water molecules together you have something awfully good to drink after climbing Mount Everest.

If you put two oxygen atoms together you have the oxygen we need to survive. If you put three oxygen atoms together, you have the ozone that protects us from the sun’s ultraviolet light. 

Experiment: Erupting Volcano.

What you need: 16 oz. soda bottle, large pan, 2 measuring cups, 1 tablespoon flour, 1 tablespoon baking soda, spoon, funnel, red food coloring, 1 cup white vinegar, water.

What to do: Place the soda bottle upright in the pan. Mix the flour and baking soda in one of the measuring cups. Pour the mixture of flour and baking soda through the funnel into the soda bottle. Add 20 drops of red food coloring. Pour in half the vinegar. When the volcano stops erupting pour in the rest of the vinegar.

What it means. The baking soda reacts with the vinegar creating carbon dioxide gas.

Variations: Vary the amount of vinegar, baking soda, and flour. What are the results? 

MORE ABOUT ATOMS ! 

Electrons and quarks have something called electric charge. This doesn’t mean they have credit cards or bank cards, but it does mean they are slightly electrical. They have negative and positive charges similar to an electrical charge on a flashlight battery. 

Electrons have only one type of charge and that’s negative.

Quarks can have either a negative or a positive charge.

Protons contain two quarks with 2/3 unit of positive charge and one quark with 1/3 unit of negative charge.

Neutrons are the opposite of protons, they contain two quarks with 1/3 unit of negative charge and one quark with 2/3 unit of positive charge.

When the nucleus forms it is made up of differing numbers of protons and neutrons, but even one proton will make the nucleus of the atom positively charged. This positively charged nucleus will attract as many negatively charged electrons as it needs to balance out the positively charged protons. Thus the entire atom has a neutral charge. 

Atoms will become negative if they gain an electron, and will become positive if they lose an electron. The negative and positive terminals of a battery or any electrical source will be charged negatively and positively and this is due to the electrical charge of the atoms at that terminal.

See "Experiment: Make a fluorescent bulb glow without plugging it in" in "MORE ABOUT LIGHT"

ELECTRICITY 

Imagine a water wheel at an old-fashioned water-powered mill. Now imagine that the water is the electricity and the wheel is the light bulb. If the water were to start flowing uphill then the mill and the waterwheel would not work properly.

Since electricity flows very much like water, electricity is said to have electric current. The electric circuit is the path the electricity follows. For a light bulb, a toaster, a computer, or anything electrical to work, electricity must make a complete circle or circuit from its source. The source can be the batteries in a flashlight, or a giant water dam that produces electricity. These giant water dams, like the Hoover Dam in Nevada, are called hydro-electric power plants. The switch on the flashlight or the switch on your wall turns the light on by completing the circuit; it turns the light off by breaking the circuit so that the electrical current cannot complete the full cycle. 

Electricity flows in a current the way river water flows in a certain direction. There are two types of electrical current: direct current (DC) and alternating current (AC). Direct current is a steady flow of electricity in one direction. Things that use direct current are flashlights, small battery-powered radios, automobiles, and solar powered appliances. LAZER VAUDEVILLE uses direct current for microphones, flashlights, and headsets used backstage for communicating with the light booth, a common practice in any theatrical production. The main sources of direct current are batteries and solar electrical panels. Batteries and solar panels use a chemical reaction to produce electricity.

Alternating current flows in both directions, in fact it changes directions 120 times every second making 60 complete cycles every second. Things that use alternating current are toasters, washers and dryers, refrigerators, and most lights in homes and schools. The main sources of alternating current are hydro-electric dams, nuclear reactor power plants, and coal or oil burning electric plants. All of these types of power plants use generators to actually make the electricity. LAZER VAUDEVILLE uses alternating current to power lasers, blacklights, sound systems, and stage lights.

Experiment: Electric lemon.

What you need: Paper clip, a lemon, copper wire.

What to do: Unbend part of the paper clip and insert in lemon. Expose both ends of the copper wire. Push one part of the copper wire into the lemon away from the paper clip. Touch your tongue to both the copper wire and the paper clip. You will feel a tingle.

What it means: You have created a mild electrical connection. Your tongue completes the electric circuit. The moistness of your tongue conducts the electricity so you can feel it. 

Safety: Direct current and alternating current have advantages and disadvantages when it comes to safety. Direct current is safe in very low levels on voltages, but it is very dangerous in higher voltages. The main advantage is that it is very portable in the batteries it comes in. Alternating current is safer at higher levels or voltages, but it can still kill people. By using alternating rather than direct current in homes, we reduce the risk of injury or death from electrical accidents. 

MORE ABOUT ELECTRICITY !

SOURCES OF ELECTRICITY 

An electrical source must have a positive charge at one end and a negative charge at the other end. The first person to recognize this property of electricity was the French scientist Charles Dufay in the 1730’s. Rather than positive and negative, he called the charges vitreous and resinous, and thought of them not as a charge but as an actual fluid.

In 1752 Benjamin Franklin flew a kite while a thunderstorm was building up and recognized that the clouds also had electrical charge. Franklin was the first person to describe this charge as positive and negative. When you connect the positive and negative ends by a wire the electric charge will flow through. An electric source may be powered by heat sunlight motion or chemical reaction. Solar cells called photovoltaic cells convert the sun’s energy to electricity. Solar cells are made from semi-conducting materials, usually specially treated silicone. Batteries use a chemical reaction to produce electricity. In the 1790’s Alessandro Volta, an Italian physicist, built the first battery using silver and zinc. It was called the voltaic pile and was the world’s first source of steady electricity.

Generators produce most of the electricity the world uses. Generators take mechanical energy, a water wheel at a dam or a steam turbine at a nuclear power plant, and turn it into electrical energy. The water wheel or steam turbine turns coils of wire near a magnet to produce electricity.

COMPUTERS 

Lazer Vaudeville uses many computers in our everyday world of keeping the show traveling from town to town. But one computer in particular memorizes and controls all the laser patterns you see during the laser sections of a LAZER VAUDEVILLE performance. This computer stores all of the information to make the patterns, then it stores the information for how long each pattern will appear to the audience. We can program each pattern down to the tenth of a second. This computer controls all three of our lasers.

To make a single laser pattern the computer is programmed with a complicated formula. It has to memorize the movement for each of the two mirrors. The "X" mirror (side to side) has to be programmed to tell it how far to move, and how fast; the same with the "y" mirror (up and down). A shutter is also controlled by the computer. The computer tells the shutter whether it should be open (the audience can see the laser) or closed (the audience cannot see the laser). So when you see the lasers going on and off extremely fast, that is the shutter being controlled by the computer.

The computer talks to the lasers through an electronic language called M.I.D.I. That is another acronym and it stands for: Musical Instrument Digital Interface

There are many uses for a computer within a modern vaudeville show. Backstage and behind the scenes LAZER VAUDEVILLE uses a computer to keep the show running. This Study Guide was typeset and printed using our computer. In each of the towns we visit, we use a CD-ROM map program to find the exact location of the theatres we play and any schools in which we may be performing. We use another CD-ROM atlas program to figure out exactly how many miles we have to drive to the next town. We also used a computer to build our home page on the internet. You can look it up at www.lazervaudeville.com. We even use a computer for sending e-mail all over the world when we perform in other countries like Japan. Please e-mail us at LazerVaudeville@msn.com if you have any questions or comments about this study guide or our show!

The first versions of the computer were not electronic, but mechanical. In 1642 the French scientist and mathematician Blaise Pascal invented the first automatic calculator. It could only add and subtract. In the 1670’s the German mathematician Gottfried Wilhelm von Leibniz improved the calculator so that it could also do multiplication and division.

In 1888 the American inventor Herman Hollerith came up with a punch card system for calculating the results of the United States census. Hollerith later used this early version of the computer to found the Computing-Tabulating Recording Company which became the International Business Machines Corporation, or I.B.M., in 1924.

John V. Atanasoff built the first special-purpose electronic digital computer in 1939, but it was controlled by electromechanical relays which had to be switched on and off, making it very slow. In 1946 J. Presper Eckert Jr. and John William Mauchly built the first electronic digital computer at the University of Pennsylvania. It contained about 18,000 vacuum tubes and occupied more than 1,500 square feet of floor space. This giant computer was called ENIAC, and could perform up to 5000 additions and 1000 feats of multiplication per second. In the 1960’s the integrated circuit known as a computer chip was invented. This allowed small computers to be developed, small enough to sit on a desk at home or in your school—the modern desktop computer!

Experiment: Computer use.

What you need: A computer with Internet access, a printer.

What to do: Log onto the Internet. Access www.lazervaudeville.com. Read about the history of the show, the performers, the wizard and Alfonzo the dragon. Go to the performer’s biographies and print them out. Send email to LAZER VAUDEVILLE after you have seen the show. Include your name, your school, your town. Write us about what you liked in the show.

What to do: Look up the LAZER VAUDEVILLE tour schedule at the LAZER VAUDEVILLE web site. Use a CD-ROM atlas to locate where LAZER VAUDEVILLE is today. Look up all the towns they play in, use a CD-ROM mileage atlas and calculate how many miles the performers drive in one year.

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