Monthly Archives: September 2013

Q: Why can some creatures walk on water yet I (a human) can’t?

Physicist: Surface tension. There are a lot of details and phancy physics behind surface tension, but the main idea behind surface tension comes from what separates liquids from gases.  Small things (like individual molecules) have a tendency to stick to … Continue reading

Posted in -- By the Physicist, Biology, Physics | 6 Comments

Q: What fair dice can be simulated by adding up other dice?

The original question was: The five platonic solids (tetrahedron, cube, octahedron, dodecahedron, and icosahedron) are often used in games to make 4, 6,8,12, and 20-sided dice respectively. However, if you renumber the dice using nonnegative whole numbers you can create … Continue reading

Posted in -- By the Physicist, Brain Teaser, Combinatorics, Logic, Math, Probability | 10 Comments

Q: How do I encrypt/hide/protect my email?

Cryptographer: Lots of people have been asking “how do I encrypt my email” or “how can I hide from NSA surveillance”. It turns out that the answer to the first question is fairly straight forward, while the second is not, … Continue reading

Posted in -- Guest Author, Computer Science, Paranoia | 4 Comments

Q: Where do the weird rules for rational numbers come from? (Dealing with fractions)

The original question was:  Why is it when we multiply fractions we multiply the numerators across  and the denominators across?  Whereas when we divide we don’t do the same?  Who came up with these rules and why do they work … Continue reading

Posted in -- By the Physicist, Conventions, Math | 7 Comments