## Gravity Explained

###### By Anupum Pant

I’m always amazed by how teachers all around the world come up with fantastic ideas to make science easier for kids. A couple of months back we saw a video of Dan Burns using a trampoline to explain the space-time warping at a Physics Teacher SOS workshop in Los Gatos High School. In fact there is even a place on the web where you can learn it to do yourself [here].

Another explanation which came around much later just takes the cake. EdwardCurrent uses a “space-time stretcher” to demonstrate how gravity, well, stretches the space-time fabric. Moreover, the material he uses to construct this teaching aid comes mostly amongst all the old stuff lying in his garage.

## Calculating Sunset Time With Your Fingers

Did you know, estimating sunset time with the help of your fingers is really very easy. This is one thing every person going for a trek should remember. I know you have smartphones which tell you the exact sunset time these days. In that case, learn it to show it off to your friends. By the time their smartphones come out of their pockets, and get unlocked, you’ll have an estimate ready.

Here’s what you do…

Stretch your arm as much as you can and count the number of fingers that can come in between the sun and the horizon. That’s it.

Each finger is about 15 minutes of remaining sun time. If four of your fingers, or one hand fits there, you can directly say that it’s one hour to sunset.

Another thing to note is – where you are on Earth roughly. Good news for people near the equator. The estimate near the equator is very close to 15 minutes per finger. However, for people trekking nearer to the poles, you might have more time than what you just estimated using this technique. Very near to poles, it is a completely different story.

When pros have 2 hands (8 fingers or 2 hours) of time left for sunset, they start searching for a shelter to spend the night.

But again, smartphones can give you really an accurate time. This simple farm trick, like the one  I shared a few days back – telling temperature with cricket sound. It is just a rough estimate. So make sure you don’t completely rely on this to get back home before it gets dark.

via [Groovy Matter] and [Lifehacker]

## Six Weeks and Ten Factorial – Bizarre Math Coincidence

###### By Anupum Pant

The number of seconds in 6 weeks might be of little importance to anyone. However there is an interesting bit of trivia related to it, or call it a bizarre mathematical coincidence. Here it is…

The number of seconds in 6 weeks, or 42 days (The answer to life universe and everything) equates to:
6 X 7 (days) X 24 (hours) X 60 (minutes) X 60 (seconds) = 3,628,800 sec
The number 362,880, on the first glance, looks like very random number. Now here is what this number is equal to…

10 factorial (denoted by 10!).
Or simply, 10 X 9 X 8 X 7 X 6 X 5 X 4 X 3 X 2 X 1 = 3,628,800

Down to a single second, the number of seconds in 6 weeks is exactly equal to the numerical 10! Very strange!

One thing you could do is split the 6 weeks calculation into factors, and see it for yourself. The result is all numbers from 1 – 10. The most amazing factoring I’ve ever seen.

If you are too lazy to calculate it yourself, go to this WolframAlpha calculation and see it for yourself. It subtracts 10! seconds from 6 weeks (the result is exactly 0). Apples and Oranges, I know, but the 6 weeks refers to seconds in 6 weeks, here.

Salutes to the person who discovered this.

First seen on [Reddit]