Brass Doorknobs of Public Restrooms

By Anupum Pant

I remember my grandma telling me to keep some water overnight in a copper pot, and in the morning, she used to drink it. I never understood why she did that. Backed by solid science, today I’m able to appreciate her age-old wisdom.

Today, to get rid of the problem causing bacteria, trusting brass doorknobs is better than trusting those triclosan lad anti-bacterial soaps. Yes, brass can kill bacteria very effectively.

Doorknobs are probably the most touched objects, especially the ones that are on the doors of a toilet at the mall. A doorknob probably even beats smartphones because a doorknob is accessible to anyone and everyone, whereas a smartphone is usually touched by a single individual.

Although, I’m not totally sure that a doorknob is really one of the most touched objects, one thing is for sure – Door knobs are the places where an incredible amount of sickness causing germs get collected. Thanks to the thousands of unclean hands coming straight from the toilet and touching the knob for the day.

And yet, you don’t often get sick after touching public restroom knobs. That is because doorknobs are normally made of brass. Brass and a couple of other metals have an ability to clean themselves – in a given amount of time these metals are able to sterilize themselves! This is called the Oligodynamic effect. Sounds like a cool name to remember because it’s easy to remember and nothing else would annoy your friends more than you bringing it up amidst conversations…

It has been tested and found that brass is able to sterilize itself in the span of eight hours. While some have tried to explain how it works, no one has been able to explain the effect in a satisfactory manner.

Other metals like silver, copper and copper alloys are able to kill bacteria better. Silver, purportedly is a very robust disinfectant. But, not many would be able to afford doorknobs made out of silver or pure copper. Instead, a far cheaper alloy consisting of copper and zinc (brass) is used to make bacteria zapping doorknobs.

Stainless steel and aluminium metals aren’t able to do this. Be careful when you have to twist doorknobs made of Steel or Aluminium. These are metals that could get you sick.


Weight of the Copper Tube with a Falling Magnet

By Anupum Pant

Remember I talked about Copper tube and a magnet a couple of days back? Turns out the same happens when you use an aluminium tube too. In short, a magnet (a strong one – neodymium magnet) when dropped into an aluminium or copper pipe falls very slowly, as if gravity stops acting on it.

It is due to the opposing magnetic forces generated by the electric field which is in turn generated by the magnetic field of the magnet (more in the link above).

That said, have you wondered what happens to the weight of the tube when the magnet is falling? Does it increase, decrease or remain the same? Just give it a guess and watch the following video.

The Royal Institution Explains:

Hit like if you learnt something today.

Everyone Knows Magnet in a Copper Tube, But this…

By Anupum Pant

I’m sure you know that if you let a strong magnet drop along a thick copper tube, the magnet falls in a very interesting manner. It falls slower than it normally should, delaying the span of the fall, as if gravity acting on the magnet mysteriously drops. If you haven’t heard about it, I’ll give it to you, you probably aren’t a YouTube addict, and that’s definitely good (and maybe also bad because there’s awesome stuff out there which you are missing). Just watch this, what I just said will start making sense…

Why does this happen?

OK, that’s pretty cool, but you knew about this little magnet-copper trick already, and you were expecting something more? You got it.

Whatever you just saw neither was a magic trick, nor was the Copper tube acting as an anti-gravity machine. This is pure science, can be easily explained by it. Here…

When a magnet moves quickly near a metal, it generates current in the metal. Here, current is generated in the Copper tube.
The current generated in the tube generates another magnetic field which opposes the magnetic field of the magnet and pushes the magnet upwards, away from the force of gravity. Gravity being stronger, pulls it down, but not with as much force because the magnet is being pushed in the other direction too. That’s the simple science behind it.
Still, someone else could explain it better on a page which is completely dedicated to explain it to you. [Here] and [Here]

But, you probably knew even that -The trick and the science behind it. So, there’s more for your-kind-of-people.

A new skill-toy that uses the same…

Feel flux. An amazing new skill toy that works on the same principle. Who would have thought, playing with gravity could get fun. The crowd funding campaign for it runs on indiegogo. Go fund it!