dot physics

Melting an ice cube takes 3.34 x 105 joules per kilogram. So a single ice cube with a mass of 50 grams would take 16,700 joules. You can already see that melting stuff takes a bunch of energy. If you want to melt a metal door, you have…

Just because you see something done in a movie, that doesn't mean you should try it yourself. Take, for example, a human running on top of a moving train. For starters, you can't be sure it's real. In early Westerns, they used moving…

If you live in the US and missed the last total solar eclipse in 2017, good news! You're about to get another chance. There will be a total solar eclipse passing through Texas and the Midwest states on April 8. Remember that in a solar…

Now stretch it really hard and quickly hold it to your upper lip, which is sensitive to temperature. You will feel that it's warmer than it was before. That's because you're adding energy to the rubber band, which increases its…

Illustration: Rhett AllainYou can see that we have a right triangle with the hypotenuse equal to the distance from the observer's eyes to the center of the Earth (R + h), with the other two sides being just R and the distance to the…

It's been crazy cold this week, even down where I live in Louisiana, thanks to an outbreak of a polar vortex. This frigid air is bad for all kinds of things, including football helmets, apparently. But it's actually a great time to…

The rubber band example does indeed have two nodes—they are at the ends of the rubber band where your fingers hold it. We only have half a wavelength in the standing wave, but there is indeed a relationship between the length of the…

This Halloween, when you grab a candy bar, pay attention to the wrapper. In the United States, a "nutrition facts" label has been required for all packaged foods since 1994, giving the serving size and the amount of sugar, protein, fat,…

This also works the other way: Incoming electromagnetic waves will get canceled by the moving charges in the Faraday cage. Your phone won't know that it’s getting a text message or call.Let’s focus for a minute on why the cage’s…

Next, I need the mass. Each car has an empty mass of 26,000 kilograms and a capacity of 34 seats, or 123 total passengers. From the clip, the train looks pretty crowded, but not at full capacity. Let's just say there are 60 people per…