Category Invensions & Discoveries

Computers save us a lot of work—and a lot of time. The processor of the computer follows step-by-step instructions-exactly and quickly. This series of steps is called a program. A program might be thousands of steps long, but the processor can run the program in less than a second.

The program is stored in the computer’s memory. It is stored as a series of 1’s and 0’s. This is called a digital code. Sometimes the code is stored on a CD-ROM or inside the computer on the hard drive. But the computer finds it when it needs it.

When you have finished a report, you tell the computer to print it. The computer sends the digital code to the printer. The printer has a microprocessor that changes the code into letters—so you and your teacher can read it.

Laser printers are the fastest printers. A beam of laser light makes an electrically charged image on a rotating, cylinder. The charged areas attract powdered or liquid ink called toner, onto the cylinder. The cylinder transfers the toner with the image onto the paper. The paper then passes through fuser rollers. These rollers seal the toner to the page so it doesn’t smear.

 

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As electricity moves through the circuits in the computer, millions of tiny switches are turned on and off. The computer reads a code of zeros and ones. Think of the code as switches in a line. The ones are switches that are turned on, the zeros are switches that are turned off.

The code is called digital. Because it uses only two numbers in different patterns, it is also called binary code. When you type an A on the keyboard, the computer stores the A in its memory as 01000001. Each time you click the mouse, or press a key, it is changed to binary code and stored in the computer’s memory.

It’s not only numbers and text — binary is used for the most complex data. From images to video frames, at the most granular level of the data, it is binary code.

For example, an image is built up of hundreds of thousands of pixels, with each pixel containing an RGB value stored in binary code.

These binary codes fill RGB and according to the intensity generated from those codes, the intensity numbers are thrown at a video driver program. That program distributes those colors to the million crystals on your screen — and an image is seen by us!

 

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Telephones have them. Most watches have them. They help make our cars safe. They make our telephones work more quickly. And space travel would be impossible without them.

They are microprocessors. They make our lives easier in many ways. A microprocessor is a type of microchip that can hold the signals needed to run electronic devices. Some microchips only store information. But if the microchip is also able to “figure things out,” then it’s called a microprocessor. A microprocessor works faster than your brain. And it can fit on the tip of your finger!

The surface of this tiny part is cut with grooves. Each groove is packed with thousands of tiny electrical switches. The switches are connected by thin metal wires. All the wires link together-a group called a circuit.

Microprocessors are also called integrated circuits. Equipment such as calculators made with integrated circuits are small, light, and easy to use.

When you use such equipment, bursts of electric currents speed along the circuits. These bursts are like messages. They tell the equipment what to do.

The most important part of a computer is its microchip, or integrated circuit. A microchip can fit on a fingertip. When seen under a microscope, the tiny grooves and wires look like a maze.

The first integrated circuit was made for the U.S. space program in 1959. Equipment on the spacecraft had to be very small. All electrical signals for the equipment were put on a strip of material called silicon. Later, circuits were made into tiny squares called silicon chips.

 

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Look at a picture of yourself. Now look at it from a different angle. Do you see another side of yourself in the picture? No, but if you were looking at a hologram you could walk around the picture and see the left side of your body, your back, your right side, your front, and the top of your head.

A hologram is an image that looks three dimensional-that is, it seems to have depth, height, and width. Some credit cards have holograms on them. Holograms also appear in advertisements, artwork, and jewellery.

A hologram is made with laser beams. A laser beam is a kind of coloured light. One laser beam is bounced off a mirror then off the subject and onto a special film. Another laser beam is also bounced off a mirror and onto the film. Where the two beams cross on the film, they make a tiny pattern of bright and dark stripes, a hologram.

Guiding a laser beam onto the film will produce light rays that seem to come from the original subject. The resulting three dimensional image appears to hover in space. You can look over, under, and around the subject. When a hologram is viewed with regular light or sunlight, the image appears with rainbowlike bands of colour.

To make a hologram of an object, such as this teddy bear, a laser is aimed into a mirror then at the object. Another laser is reflected off a mirror and then onto the film. The film records the hologram.

 

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Is a DVD the same thing as a CD? Although DVD’s looks like CDs, they are different. A DVD works like a CD, but it can hold more information. A CD usually records only sound, but a DVD records pictures as well as sound.

Each side of a DVD can contain two layers. Each of these layers can store data. CD’s have only one layer of information.

Before CD’s and DVD’s were invented, people used cassette tapes and videotapes. Cassette tapes record and play sounds, and videotapes record and play sounds and images.

Cassette tapes, videotapes, CD’s, and DVD’s can be played again and again. That’s one of the reasons people like them so much.

A DVD can be played in a DVD player. A DVD player is often connected to a television set. When a DVD is played, pictures appear on the TV screen and sound comes out of speakers.

 

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Cassette tapes sound good when they are new. But after a while, they start to sound scratchy. A compact disc, or CD, produces much better sound. It is played using a special light called a laser beam. Only the beam of light touches the CD, so it stays like new.

Sound is stored on a CD in a digital (numerical) code-a string of 0’s and 1’s. When a CD is made a microphone turns sound vibrations into electrical signals. Then a machine changes the signals into a digital code.

This code is fed into a powerful laser. As a blank disc turns, the laser cuts billions of tiny pits that represent the digital code into the surface of the disc.

Inside a CD player is another, less powerful, laser. When the CD is played, the laser reads the position of the pits. The laser reads from the centre to the edge of the disc as the CD turns. These pulses of light are turned into electrical signals. The signals make the speakers vibrate. Then you hear the sounds.

Inside a CD player, a laser beam shines on a mirror and through a lens onto the pits on the CD. When the beam hits a pit, the light is scattered. When it hits between pits, the light is reflected straight back. A sensor reads the patterns of reflected light and turns the patterns into electrical signals. These signals are used to produce sounds.

 

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