Rhett Allain

Hammond

Contributing Writer at Medium

https://t.co/6NnvyopzvQ Physics faculty. Physics blogger. @WIRED @MacGyverCBS and @MythBusters. Physics, Science, Geek. Coffee is my superpower.

Articles

The Golden Dome vs. Physics: Is This A Good Idea?

1 week ago | rjallain.medium.com | Rhett Allain

In case you weren’t paying attention (I can hardly blame you), Trump signed an executive order directing the creating of a missile defense system called the Golden Dome. I’m not so sure this will work, but I’m positive that the name is stupid. I bet Trump was thinking about the Israeli defense called Iron Dome. If an Iron Dome is good, wouldn’t a GOLD dome be EVEN BETTER? The idea is create a way to intercept incoming ballistic missiles as well as hypersonic and cruise missle.
Visualizing Faraday’s Law with Python

2 weeks ago | rjallain.medium.com | Rhett Allain

Sometimes it’s easier to actually calculate the real thing than it is to make a drawing. Here’s a case where that’s true — showing the induced electric field due to a changing magnetic field. This is also known as Faraday’s Law and it’s one of Maxwell’s equations. Here’s a quick reminder about Faraday’s Law. The very short version is that changing magnetic fields create electric fields.
Physics Question: What Happens to Force on the Block When It’s Tilted?

3 weeks ago | rjallain.medium.com | Rhett Allain

Here’s a great physics question for you. A block with mass of 1 kilogram sits on a horizontal table at rest such that the table pushes up on the block with a force of 9.8 Newtons. Nothing crazy there. Next, I tilt the table so that it is 30 degrees above the horizontal but the block stays at rest (it doesn’t slide). What is the new force the table exerts on the block? Here’s a small hint: I got this question wrong. Do you have an answer? If your answer is 8.49 Newtons, that’s not correct.
The Phony Physics of Star Wars Are a Blast

1 month ago | technewstube.com | Rhett Allain

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The Phony Physics of Star Wars Are a Blast

1 month ago | wired.com | Rhett Allain

I'm a huge fan of Star Wars. The first movie (no, not Episode 1) came out when I was young, so I grew up thinking about the Millennium Falcon and lightsabers. Perhaps it sparked my interest in science—even if it's not exactly science fiction. Oh, there's a nice way to start a nerd fight: Is Star Wars “science fiction” or is it “space fantasy”? Either way, you have to admit there are things in there that look like science.
The Phony Physics of Star Wars Are a Blast

1 month ago | flipboard.com | Rhett Allain

2 hours agoThese elements of ‘Star Wars’ stories might seem like science fiction but are actually real. Just 48 short years ago, movie director George Lucas used the phrase “A long time ago in a galaxy far, far away” as the opening to the first Star Wars movie, later labeled Episode IV: A New Hope. But at least …
Calculus is Weird. Why Is the Area Related to the Slope? Fundamental Theorem Explained.

1 month ago | rjallain.medium.com | Rhett Allain

In case you didn’t know, calculus is weird. In the intro class, there are really just two big ideas: derivatives and integrals. We can say that the derivative of a function is a way to describe the slope at different points. That’s cool. For integration, it’s essentially the area under the curve of the function. Nice. Now for the crazy part. The area under the curve is the opposite of the slope. OK, that’s not exactly true — but an integral is an anti-derivative.
Pew Pew… But How Fast? A Physics Investigation of Star Wars Blaster Bolts

1 month ago | rjallain.medium.com | Rhett Allain

A long time ago in a different blog, I did an analysis of the speed of blaster bolts. Well, the internet does not preserve things like we would hope and my original analysis is all borked. It’s time to redo this. We know that the stuff that comes out of a blaster in Star Wars is not a laser. I mean, if they were laser guns you wouldn’t really see much unless the beam was hitting you. Also lasers are light and travel at the speed of light (about 3 x 10⁸ meters per second).
Lenz’s Law Is Confusing for Many Physics Students - Here’s How It Really Works

1 month ago | rjallain.medium.com | Rhett Allain

In the algebra-based physics course, the second semester gets pretty dicey. There’s a bunch of important things in there — but much of it depends on vector calculus. However, since it’s an algebra-based course the students don’t have the calculus stuff. That means they are left with some equations that might just seem like magic. The concept that I see students struggle with often is Lenz’s Law. So, I’m going to do my very best to explain how this works and what it does.
ある物理実験が教えてくれる、「役に立たない」科学に投資すべき理由

1 month ago | wired.jp | Rhett Allain

よくある話だ。政治家は、政府が資金を出している“くだらない科学プロジェクト”に文句をつけ、納税者の不満をあおる。そうしたくなる気持ちもわからないでもない。非常に高価な粒子加速器も、ペチュニアの色についての安価な実験も、金の無駄に思えるのだろう。ビジネスの観点から見た場合、そう思うのも無理はない。とはいえ、仮に収支だけを重視したとしても、誰にも予測できない「波及効果」まで含めて考えれば、こうしたプロジェクトは結果的に大きな利益をもたらすことが多い（ペチュニアの話もぜひ読んでほしい！）。ここで、一見大したことのようには見えないが、実は驚くほど高い費用対効果を発揮した小さな実験を紹介しよう。ヘルツの実験ジェームズ・クラーク・マクスウェルが、後に「マクスウェルの方程式」として知られる電磁気学の基礎となる一連の方程式を発表したのは1862年のことだ。このころ、人類はようやく電池や電流の性質を研究し始めた。マクスウェルが提唱した4つの方程式の最初の2つは、静止した電荷の周囲に存在する電場と磁場を表している。...