Mad About Science: Everyday science

By Brenden Bobby
Reader Columnist

There are some things in our lives that may as well be magic. Wave a wand, say the magic word, plug it into an outlet and voila — your task is complete. Ever wonder how some of this everyday technology works? I have, and luckily some of that everyday tech makes it very easy to find out how other tech works.

Vacuum cleaners

If you’re reading this paper, chances are you’ve encountered a vacuum cleaner at some point in your life. Ever wondered how it works?

The device, seemingly magic, sucks virtually anything up and away to clean your house in a few easy minutes. It achieves this by creating negative pressure in an enclosed space. That likely means a whole lot of nothing to you, so think about it like this: When you use your lips to suck liquid up through a straw, one of the things you’re doing is creating negative pressure inside of the straw. 

Air functions to equalize pressure wherever it is, so when air is moved, other air — or liquid, in the case of a straw — moves to equalize the pressure within the structure and flows with the same energy that was applied to move the initial air. 

To further simplify this, imagine if you’re standing in a line for your favorite breakfast burrito. The faster the chef makes the burritos, the more quickly the line moves. In this case, the line is a straw, the chef is your lips and you are the air.

A vacuum cleaner performs this mechanically by using a bladed fan attached to an electric motor that pulls in air by creating negative pressure. As air moves to equalize the pressure, it’s pulling other objects like dust and debris along with it. Normally, this would cause all of that junk to simply spray out the opposite end of the vacuum cleaner — after all, the air has to go somewhere, otherwise the vacuum cleaner would just fill up and stop working. 

The air and everything else it’s carrying is directed through two filters. Air molecules are very small and able to pass through the filter and shoot through the exhaust port of the vacuum, while the larger and heavier debris get trapped in the filter and dust bag of the cleaner.

This is virtually the same process that happens in the pneumatic tubes you use at the bank. At one time, mail was transported this way, particularly in large metropolitan areas and housing complexes, though the postal service now tends to favor conveyors and sorting machines, as these are easier to maintain and supervise than airtight tubes that can get jammed.

NFC

I know what you’re thinking; and, no, we aren’t talking about non-fungible tokens. The internet can keep its ridiculous million-dollar screenshots.

NFC is an abbreviation for “near-field communication.” If this term is foreign to you, that’s understandable, but its function is very familiar. Chances are, you use it every time you pay for coffee or gas.

NFC technology is in most of our phones and all of our credit and debit cards. The chips in your card are equipped with a tiny transmitting and receiving antenna for sharing data with a console that also possesses a transmitter and receiver. 

The transmitters send information through radio waves at very close distances, usually within less than an inch. This ensures that the act of transmission is intentional and crafty thieves aren’t skimming your credit card information while you walk through the cafe. 

An evolution of RFID, or radio frequency identification technology, the bulk of NFC tech is found in the financial sector to transmit payment securely through point-of-sales systems and vendors. It had been briefly used to transmit data between smartphones, but touching smartphones is such a bizarre and invasive concept that it understandably never caught on.

Wireless charging

This may as well be magic, and the real nuts and bolts of how this works is better explained by an electrical engineer than some guy who works at a library.

Nevertheless, more than a few of us are likely curious about how this magical power transmission works and why it takes 15 attempts to perfectly position your phone, just for it to buzz right out of position when it signals to you that it’s charging.

The electricity coming from your wall is an alternating current, which means the electrons in the current will reverse direction several times per second, swapping back and forth. Talk to your friendly neighborhood electrician about why this is important. 

Electrons traveling through a coil embedded in your wireless charger generate a magnetic field. Due to the alternating current, the magnetic field will occasionally reverse. There is a magnet Inside your phone that is also wrapped in an electrical coil, which is connected to your battery. Electrons trapped within the coil are manipulated by this rapidly switching magnetic field, which pushes and pulls them through a process called magnetic induction.

If you’re lost, don’t worry — I am, too.

If you want to see a less magical version of how this works, look up videos about AA batteries as electric trains. 

A user will place magnets on either end of a battery and then set that battery into a copper coil that spans several feet. As the electrons travel through the completed circuit, it generates an electromagnetic field that then propels the battery through the copper coil. 

This does, however, expend the energy of the battery, so that it’s not a perfect representation of what’s going on with your phone’s wireless charger, but it sure is fun to watch.

We’re surrounded by so much cool technology that we take for granted. While it might seem like magic, all you need is a little curiosity and a few extra minutes a day to devote to learning something new.

Stay curious, 7B.