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!)
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.
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.
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.
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.