Some fun technology facts

What makes Velcro stick?
by Ben Biggs, 9 May 2012
Discover the small-scale engineering behind the invention of Velcro
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Velcro works by having two strips of material, one with lots of tiny hooks, and one with lots of thinner loops that the hooks can cling to when the two elements are pressed together. This mechanism of sticking was inspired by the way tiny hooks on the seeds of burdock, known as burrs, attach to animal furs and human clothing.
The hooks and loops in Velcro are commonly made from nylon and polyester with the hooks being more rigid and thicker than the loops.
The more hooks and loops that are attached per unit area, the stronger the bond with heavy-duty Velcro containing up to 400 hooks and loops per square inch. In some cases a five-centimetre (two-inch) square piece of Velcro is enough to support a 79-kilogram (175-pound) person.
How does a washing machine work?
Most homes are lucky enough to have one, but have you ever wondered how a washing machine works? After separating your laundry into whites and colours – so as to protect your whites from colour run – load your clothes into the main drum and close the door. Once you’ve programmed the machine to tell it what sort of wash you require – temperature, speed, length and so on – the machine then adds water and detergent and sloshes the clothes around. After a time, the drum will spin really fast – up to 80mph (130kph) – creating a centrifugal force that extracts most of the water out of the clothes and out through the holes in the inner drum where it is then pumped away.
‘Pixel’ is short for Picture Element. When we see graphic images on digital devices the display divides the screen into thousands or millions of pixels, arranged in rows and columns. Each pixel has its own address in this grid and is represented by dots or squares. Pixels build up a sample of an original image and are the smallest component of a digital image. The more pixels used to represent an image, the closer it will resemble the original.
The number of pixels used to create an image is often referred to as the ‘resolution’. The best digital cameras have the highest pixel count because they produce a higher-quality image. In colour images a pixel is typically comprised of three of four colour dots – a red, a blue and a green. When these colour dots converge, they build coloured pixels. You might have spent most of your youth playing Mario games with 256 x 224 pixels – now a typical HD monitor can display 1,366 x 768 pixels.
How does voicemail record messages?
by Jonny O’Callaghan, 20 November 2011
What happens after someone leaves you an answerphone message?
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Voicemail works by monitoring the electromagnetic waves used to carry phone signals. If you’re busy, or your phone is off, the message is stored in a ‘mailbox’, essentially another line to which calls are diverted after a certain time. This mailbox records the exact nature of the electromagnetic wave that was sent, including the differences in volume and frequency in the human voice.
These impulses are then encoded into ASCII, a binary system that renders them into 0s and 1s. Once this is done, the phone is capable of playing it back as a stream of binary data, which includes the frequency and volume of the voice that left the message. When you hit playback, the resonating elements of the phone, including the speaker itself, use that stream of binary code to re-create the voice call for you to listen to.
How does Kevlar stop a bullet?
by Jonny O’Callaghan, 6 February 2012
We’ve got the answer right here
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Kevlar is able to stop a bullet due to its molecular structure. It is a light, polyarylamide plastic fabric, which has a high tensile strength. this means it takes a huge amount of energy to make its fibres stretch even a little. Each Kevlar molecule looks like a long twisting coil. During polymerisation these coils of molecules become tangled, causing it to be hard to stretch.
Inside a bulletproof vest are many strips and layers of Kevlar. When a bullet hits the vest, it tries to force it through the layers, but to do this it must push the fibres apart. The fibres are woven and resist this very effectively. The movement is translated into a stretching force on the fibres. Some will break, but most will absorb the energy of the bullet by stretching a small amount.
How do fuses work?
by Jonny O’Callaghan, 13 November 2011
Find out why blowing a fuse is actually a good thing.
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Fuses are essentially fire breaks, points of deliberate weakness that, if power surges through a house’s electrical system, will collapse to prevent damage or fire. This is achieved by the fuse’s central component, a strip or strand of metal which has a lower breaking capacity. The metal’s breaking capacity is the maximum current that can be passed through it safely, while anything above that will cause it to melt and break the circuit. Zinc, copper, silver and aluminium are all commonly used as fuse wire.
The fuse wire is then placed between two terminals, wrapped in a non-conductive material and then put in place. Then, if a power surge happens, the fuse will break, severing the connection, closing the circuit and minimising further damage.
How does Wi-Fi work?
by Jonny O’Callaghan, 3 October 2011
Here’s our quick guide to wireless Internet.
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Asked by Jacob
Most people use a router to connect to the internet. This gadget sends and receives information from a phone line or TV cable, and can handle this information, connecting to several computers around the house or office at the same time.
The computers can be plugged into the router using a network cable, but Wi-Fi is more convenient as it uses radio signals. The wireless device in the computer and router then work like two-way radios, sharing large amounts of information.
The router can use different radio channels, but the information packets are addressed to a specific machine. To ensure the communications stay safe, there are different ways to encrypt it, and that’s why you need to set up a password.
José Monteiro, Sci

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velcroVelcro

We all love Velcro – it’s a great alternative to buttons and zipper, but do you know how it works?

Velcro works by having two strips of material that can hold themselves together.  One strip has loads of tiny hooks – the other has loads of thin loops that the hooks can cling to when the two strips are pressed together.

Velcro was invented in 1948 by the Swiss electrical engineer George de Mestral, and it’s said that his inspiration came from the way that the seeds of burdock, known as burrs, stick to animal furs and your clothing.

The more hooks and loops that a strip of Velcro has, the stronger the hold that it has.  Really heavy-duty Velcro is strong enough to support a human (but don’t try this at home!)

PixcelsPixels

Our TV’s have them as do our cameras and phones, but do you know what a pixel is?

Pixel stands for ‘Picture Element’.  The display on a digital devices divides the screen into thousands or millions of pixels, arranged in rows and columns.

Each pixel has its own address in this grid and is represented by dots or squares, and the more pixels used, the closer the created image will resemble the original image.

The number of pixels used is often referred to as resolution, and high quality digital cameras will have the highest pixel count as they need to produce higher-quality images.

VoicemailVoicemail

You might be in a class or playing sport when mum calls, so she leaves a message.  But do you know what  happens when someone leaves you an answerphone message?

Voicemail works by monitoring the electromagnetic waves used to carry phone signals. If you’re busy, or your phone is off, the message is stored in a ‘mailbox’, essentially another line to which calls are diverted after a certain time.  This mailbox records the exact nature of the electromagnetic wave that was sent, including the differences in volume and frequency in the voice.

These impulses are then encoded into ASCII, a binary system that renders them into 0’s and 1’s.  Once this is done, the phone is capable of playing it back as a stream of binary data, which includes the frequency and volume of the voice that left the message. When you hit playback, the resonating elements of the phone, including the speaker itself, use that stream of binary code to re-create the voice call for you to listen to.

FusesFuses

All electrical devices have fuses in their plugs, but do you know where fuses are there?

Fuses are essentially fire breaks – points of weakness that if there was a power surge, will break to prevent damage or fire.

This is achieved by the fuse’s central component, a strip or strand of metal which has a low breaking capacity. The metal’s breaking capacity is the maximum current that can be passed through it safely, while anything above that will cause it to melt and break the circuit. Zinc, copper, silver and aluminium are all commonly used as fuse wire.

The fuse wire is placed between two terminals, wrapped in a non-conductive material and then put in place. Then, if a power surge happens, the fuse will break, severing the connection, closing the circuit and minimising further damage.

Wi-FiWi-Fi

Most people have lap-tops or tablet devices at home that access the internet without any wires, by using Wi-Fi.  But do you know what Wi-Fi is?

To connect to the internet, every home needs a router – this is a gadget that sends and receives information through a phone line or TV cable, connecting to several computers around the house or office at the same time.

Computers can be plugged into the router using a network cable, but Wi-Fi is more convenient as it uses radio signals. The wireless device in the computer and router work like two-way radios, sharing large amounts of information.  Whilst a router can use different radio channels,  the information carried is addressed to a specific machine. To ensure the communications stay safe, there are different ways to encrypt it, and that’s why you need to set up a password.

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