Physics Weekly Newsletter
Physics Weekly Newsletter

Top new questions this week:

Which ball touches the ground first?

This is a very well known problem, but I can't find an answer in the specific case I'm looking for. Let's consider two balls : Ball 1 weighs 10 kg Ball 2 weighs 1 kg Balls have identical volumes …

homework newtonian-mechanics newtonian-gravity drag free-fall  
asked by FlipFlapFlop 25 votes
answered by Bernhard 43 votes

Is this really a golden ratio spiral?

In this blog post, I found this picture: Does the water really form golden ratio spiral in such cases? Or is the photo just a provocative example, without physics grounds for claims about …

fluid-dynamics everyday-life  
asked by VividD 23 votes
answered by Emilio Pisanty 21 votes

Why is the pressure inside a soap bubble higher than outside?

Apparently, the air inside a soap bubble is under higher pressure than the surrounding air. This is for instance apparent in the sound bubbles make when they burst. Why is the pressure inside the …

pressure air surface-tension  
asked by David Zwicker 19 votes
answered by David 32 votes

Is the frequency of light restricted?

What are the factors that limit the frequency of light? Can it have wavelengths ranging between zero and infinity?

electromagnetic-radiation visible-light frequency wavelength  
asked by Afrish Khan 14 votes
answered by LDC3 6 votes

Pool in a submarine

A common theme in aquatic science fiction is the submarine pool/access to the ocean. That terrible TV show Seaquest had it, The Deep & Deep Blue Sea (Samuel L Jackson is standing in front of it …

asked by George R 14 votes
answered by bowlofred 13 votes

Is speed of light and sound rational or irrational in nature?

Just as circumference of circle will remain $\pi$ for unit diameter, no matter what standard unit we take, are the speeds of light and sound irrational or rational in nature ? I'm talking about …

speed-of-light mathematics physical-constants  
asked by kaka 13 votes
answered by David Z 45 votes

Evidence of why the Standard Model is a successful theory of particle physics

When discussing physics with laypersons, I'm often in the situation where I have to explain what the Standard Model is, and why it's a successful theory of particle physics. To help in such …

experimental-physics standard-model  
asked by Mark B 12 votes
answered by PhotonicBoom 16 votes

Greatest hits from previous weeks:

How does water evaporate if it doesn't boil?

When the sun is out after a rain, I can see what appears to be steam rising off a wooden bridge nearby. I'm pretty sure this is water turning into a gas. However, I thought water had to reach 100 …

water temperature evaporation  
asked by Crummy 20 votes
answered by Peter 17 votes

What is the difference between "kinematics" and "dynamics"?

I have noticed that authors in the literature sometimes divide characteristics of some phenomenon into "kinematics" and "dynamics". I first encountered this in Jackson's E&M book, where, in …

kinematics terminology  
asked by nibot 28 votes
answered by Chad Orzel 17 votes

Can you answer these?

S-Matrix Generating Functional (Problem 4.1 in Weinberg)

I'm currently working through Weinberg's QFT book, but I'm somewhat stuck at problem 4.1, which states: Define generating functionals for the S-matrix and its connected part: \begin{equation} …

homework quantum-field-theory feynman-diagram s-matrix-theory  
asked by Lurianus 2 votes

What is the advantage of segmented particle traps?

I'm currently trying to familiarize myself with the physics of ion and particle traps, especially with linear Paul traps. Many scientific experiments I've come across use segmented electrodes (like in …

experimental-physics ion-traps  
asked by Sentry 3 votes

Point of rotation appears as an ellipse when calculated from gps coordinates

First question here. Feel free to write if I posted in the wrong place. While rotating a ship as accurately as we can around some point within the ship, we can calculate the point of rotation from …

asked by Nicolai 1 vote
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