Yearly Archives: 2013

Q: Is it a coincidence that a circles circumference is the derivative of its area, as well as the volume of a sphere being the antiderivative of its surface area? What is the explanation for this?

Posted on February 9, 2013 by The Physicist

Physicist: For those of you not hip to the calculus groove, here’s what’s going down:  The derivative of Y with respect to X, written , is just a description of how fast Y changes when X changes.  It so happens … Continue reading →

Posted in -- By the Physicist, Math | 14 Comments

Q: If hot air rises, why is it generally colder at higher elevations?

Posted on February 3, 2013 by The Physicist

Physicist: Beautiful question! The short answer is that if you have a warm bubble of air it will rise, but as it does it’ll expand in the lower pressure environment, which causes it to cool. If you’re not familiar with … Continue reading →

Posted in -- By the Physicist, Physics | 10 Comments

Q: What is quantum teleportation? Why can’t we use it to communicate faster than light?

Posted on January 29, 2013 by The Physicist

Physicist: Contrary to its exciting name, quantum teleportation doesn’t involve any physical stuff suddenly disappearing and then reappearing somewhere else.  Instead it’s a cute, clever, technique for transferring an unknown quantum state of one system (usually a single particle) to … Continue reading →

Posted in -- By the Physicist, Entropy/Information, Physics, Quantum Theory | 28 Comments

Q: Since all particles display wave-like characteristics, does that imply that one could use destructive wave interference to destroy or at least drastically change a particle?

Posted on January 24, 2013 by The Physicist

Physicist: The wave-like property of particles allows you to do a lot of cute things with particles that would otherwise seem impossible, but making a particle disappear isn’t one of them.  You can use destructive interference to make it very … Continue reading →

Posted in -- By the Physicist, Particle Physics, Physics, Quantum Theory | 4 Comments

Q: How does the Oberth Effect work, and where does the extra energy come from? Why is it better for a rocket to fire at the lowest point in its orbit?

Posted on January 19, 2013 by The Physicist

Physicist: When a rocket fires it increases its speed by some fixed amount called the “ΔV” (delta V).  If the original speed is W, and the rocket speeds up by ΔV, then the change in energy is: .  So here’s … Continue reading →

Posted in -- By the Physicist, Physics | 27 Comments

Q: How do lenses that concentrate light not violate the second law of thermodynamics? If you use a magnifying glass to burn ants, aren’t you making a point hotter than the ambient temperature without losing energy?

Posted on January 13, 2013 by The Physicist

Physicist: This is a surprisingly subtle question. It certainly impossible to create new energy, but there’s nothing to stop you from piping energy from one place to another (say, by running hot water from a boiler to somewhere else).  The … Continue reading →

Posted in -- By the Physicist, Entropy/Information, Physics | 55 Comments