Category Archives: Brain Teaser

Q: How many mathematicians/physicists does it take to screw in a light bulb?

Mathematician: Theorem (Bulb Screwing) It only takes one mathematician to screw in a light bulb. Proof: Let the “bulb screwing number” of a profession , be the minimum number of people of profession that must be assembled to screw in … Continue reading

Posted in -- By the Mathematician, -- By the Physicist, Brain Teaser, Philosophical | 17 Comments

Q: Why is it that (if you exclude 2 & 3) the difference between the squares of any two prime numbers is divisible by 12?

Physicist:  That’s a really cool property! Every prime number (other than 2 and 3) can be written in the form 6j+1 or 6j+5.  For example, 17 = 6(2)+5 and 31 = 6(5)+1. This is because numbers of the form 6j, … Continue reading

Posted in -- By the Physicist, Brain Teaser, Math, Number Theory | 3 Comments

Q: How do “Numerology Math Tricks” work? (adding digits and tricks with nines)

The original question was: Please help me solve this math card trick, I do not understand how it works: If you take a deck of 52 cards and split it into any number of piles (lets say 3) and count … Continue reading

Posted in -- By the Physicist, Brain Teaser, Math, Number Theory | 7 Comments

Q: If you could see through the Earth, how big would Australia look from the other side?

The original question was: Relative to the size my feet appear when I’m standing up and looking at the ground, how large would Australia appear if I could see all the way through the Earth and observe its shape?  Also, … Continue reading

Posted in -- By the Physicist, Brain Teaser, Geometry | 1 Comment

Q: What would happen if an unstoppable force met with an unmovable, impenetrable object?

Mathematician: Sometimes, when we don’t use language carefully enough, we can get ourselves into philosophical trouble. For example, consider the following statement: If a barber shaves all those men (and only those men) who do not shave themselves, does he … Continue reading

Posted in -- By the Mathematician, Brain Teaser, Philosophical | 8 Comments

Q: If you were to break down an average human body into its individual atoms, and then laid the atoms out in a single straight line, how far would it stretch?

Physicist: Atoms are a little “fuzzy”, so their exact size is a little tricky to define.  So taking their size in terms of bond length, and looking at the most common elements in the human body (by mass: 65% oxygen, … Continue reading

Posted in -- By the Physicist, Biology, Brain Teaser | 2 Comments