Category Every Day Science

Shopping carts (also known as shopping trolleys or shopping baskets in some parts of the world) are a great example of a simple machine at work. They consist of only two main parts: a metallic basket and a set of wheels. The basket has a handle attached to it (which helps in steering the cart), and it’s installed above a set of four small wheels that make pushing, pulling and steering the cart very convenient.

It’s quite clear that a shopping cart consists of very simple components, but it is of tremendous assistance to shoppers while they roam throughout the shopping mart looking for a particular flavor of cookie or a big bottle of anti-dandruff shampoo.

In some countries, including India, the United Kingdom and Australia, there is a rather queer problem with trolleys; they seem to have a mind of their own! Suppose you try to turn a trolley towards, say, the left. It would definitely turn, but not towards the left; it would either go towards the right or move straight ahead. The same thing happens when you push them in the forward direction; it goes left or right unless you apply a surprisingly large amount of force to move it in the desired direction.

 

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The earliest wheel and axle machines were used as potter’s wheels. A potter’s wheel is a flat, round stone. By applying effort to a pedal, the potter makes the stone spin on its axle. The potter works a piece of clay between her hands on the spinning stone, shaping the clay into a pot. Clay pots were very important in everyday life in ancient times. They were used to store food, water, and medicines.

A potter’s wheel may occasionally be referred to as a “potter’s lathe”. However, that term is better used for another kind of machine that is used for a different shaping process, turning, similar to that used for shaping of metal and wooden articles.

The techniques of jiggering and jolleying can be seen as extensions of the potter’s wheel: in jiggering, a shaped tool is slowly brought down onto the plastic clay body that has been placed on top of the rotating plaster mould. The jigger tool shapes one face, the mould the other. The term is specific to the shaping of flat ware, such as plates, whilst a similar technique, jolleying, refers to the production of hollow ware, such as cups.

 

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CD-ROM’s are important tools for computer users. CD-ROM’s are discs that store words, music, and images. Encyclopedias, games, and other programs that would require greater storage capacity can fit onto one CD-ROM. CD-ROM stands for computer disc read-only memory.

When you put a CD-ROM into your computer’s drive, files are copied from the disc to the computer’s hard drive. These files tell the computer how to access all the information on the CD-ROM.

A DVD (digital video disc) is the same size as a CD-ROM but can store much more information. Unlike a CD or CD-ROM, the DVD is able to record data (information) on both the top and the bottom of the plastic disc. And it can record two layers of data on each side. A DVD player can also play CD-ROM’s.

A DVD contains layers of digital data encoded in tiny pits. In a DVD player, a lens focuses a laser beam on the desired layer. As the disc rotates, the pits and the flat areas between them reflect patterns of light to a photo detector, which changes the patterns into electrical signals. A single layer of a DVD has more pits, placed closer together, than an ordinary CD has, and so can store more data.

 

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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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