# Can You Solve Einstein’s Riddle?

Original article by Danielle Andrew in IFL Science

photo credit: InformiguelCarreño/Wikimedia

The following riddle is claimed to have been written by Einstein as a boy. It’s also sometimes attributed to Lewis Carrol, although there’s no evidence that either of them actually wrote it. Either way, it’s fiendishly clever and is popularly called “Einstein’s riddle”. It’s rumored that only 2% of the world can solve it.

See if you can figure it out:

There are five houses in five different colors in a row. In each house lives a person with a different nationality. The five owners drink a certain type of beverage, smoke a certain brand of cigar and keep a certain pet. No owners have the same pet, smoke the same brand of cigar, or drink the same beverage. Other facts:

1. The Brit lives in the red house.
2. The Swede keeps dogs as pets.
3. The Dane drinks tea.
4. The green house is on the immediate left of the white house.
5. The green house’s owner drinks coffee.
6. The owner who smokes Pall Mall rears birds.
7. The owner of the yellow house smokes Dunhill.
8. The owner living in the center house drinks milk.
9. The Norwegian lives in the first house.
10. The owner who smokes Blends lives next to the one who keeps cats.
11. The owner who keeps the horse lives next to the one who smokes Dunhill.
12. The owner who smokes Bluemasters drinks beer.
13. The German smokes Prince.
14. The Norwegian lives next to the blue house.
15. The owner who smokes Blends lives next to the one who drinks water.

The question is: who owns the fish?

There are no tricks, all it requires is simple logic. Those that haven’t the patience to work it out can watch PoETheeds’ video, which takes you through the process of solving it step by step.

## How many chess games are possible?

A commonly cited fact is that there are more possible games of chess than there are particles in the observable universe. How can this be? Another great video by Numberphile.

## That Viral Math Problem (Cheryl’s Birthday)

Simon Pampena gives his take on THAT viral math problem from Singapore on Numberphile.

## 5 of my favourite YouTube Channels

This is the first of a series of ‘5 of my favourite …’ that I hope to blog in the coming weeks.

Many, if not most, people have a Gmail account. However, not many realise this means they can use the same login for YouTube to upload videos and/or subscribe to various YouTube channels. Subscribing to good YouTube channels is a must for parents and (older) children. Below are 5 of my favourite science YouTube channels (plus a bonus).

1. Veritasium

Veritasium is the brainchild of my mate and former research colleague Derek Muller. Building on his PhD thesis which examined the use of video and multimedia in physics education and addressing misconceptions, Derek has developed one of the top science YouTube channels with over 2 million subscribers and over 127 million views! With his charismatic persona, interesting and varied topics and ever increasing cinematography, Veritasium is a must watch channel to subscribe to. Here is one of his excellent repertoire:

2. Minute Physics

My claim to fame is that when Derek was starting out I suggested he contact Henry from Minute Physics to compare notes and collaborate (this happened). Minute Physics is a very well established, high quality YouTube channel using succinct, stop motion, hand drawn animations to explain some some extremely varied and interesting physics concepts. Here the true science of parallel universes is explained:

3. Periodic Videos

Another staple is Periodic Videos from Brady Haran and the University of Nottingham. Featuring the excellent, eccentric, quintessentially crazy-haired Professor Sir Martyn Poliakoff, Periodic Videos brings us some fascinating chemistry videos for young and old alike. This ‘barking dog’ reaction in slow motion is a great example:

4. AsapSCIENCE

Another very well established (over 3 million subscribers) channel using stop motion animation to explain all manner of topics is AsapSCIENCE. To quote ScienceDump “I swear if AsapSCIENCE were my A level teachers, I’d be so happy, [an] entertaining way to learn rather than the standard textbook!”. Let AsapSCIENCE explain which came first – the chicken or the egg?:

5. SciShow

SciShow is a great YouTube science magazine-style channel with very appealing (and fast!) presentations and animations, covering all aspects of science. In this video SciShow explains how dogs really listen to us, and how pufferfish puff:

Bonus: Numberphile

I had to include Numberphile as a math-tastic channel, also by Brady Haran. I have always loved maths but the passionate and quirky mathematicians featured in Numberphile have brought the interest level of maths to another level. Did you know there was a mathematical way to choose a toilet?:

## Do ‘i’ Really Exist

“Sad to say this but you are imaginary. We need to get to the root of this problem.”