Relativity Isn't Relative

On their 20th birthday, identical twin astronauts volunteer for an experiment. Terra will remain on Earth, while Stella will board a spaceship. Stella's ship will travel to visit a star that is 10 light-years away, then return to Earth....

In just a matter of seconds, hummingbirds can perform astonishing aerial acrobatics, eat lunch in midair, pollinate a flower, even escape threats while upside-down. And they can do this all while achieving sustained hovering flight— an...

Have you ever wondered why 75% humidity in the summer feels sticky, but 75% humidity in the winter feels super dry? Turns out, the common definition of humidity is inconvenient and confusing. But there is a better way!

Hank talks about space elevators, and why we shouldn't expect to see one any time soon.

We all know tides have something to do with gravity from the Moon and Sun, but if gravity affects the motion of all objects equally, then how come oceans have large tides while other bodies of water don't? It's because your mental...

This video is chapter 6 in my series on special relativity, and it covers the topic of relativistic addition of velocity: aka, how things that are moving relative to one inertial reference frame, which is moving relative to another...

"How fast are you moving?" seems like an easy question, but it's actually quite complicated -- and perhaps best answered by another question: "Relative to what?" Even when you think you're standing still, the Earth is moving relative to...

Your rich, eccentric uncle just passed away, and you and your 99 nasty relatives have been invited to the reading of his will. He wanted to leave all of his money to you, but he knew that if he did, your relatives would pester you...

In this video Paul Andersen explains how the dimensions of space and time are combined in relativistic mechanics. Gravity and velocity can affect both space and time according to Albert Einstein's Special Law of Relativity.

How Einstein (& others) discovered Special Relativity. Pi day (3.14) is Albert Einstein's Birthday! To celebrate, we'll explain 4 of his most groundbreaking papers from 1905, when he was just 26 years old.

Male birds have the largest genital diversity of any class of animals because their sex chromosomes make it easy to pass male-helping mutations down the...

From wasps nests to nuclear reactors. Here are just a few clever ways archeologists figure out how old something is.

New ReviewFriction always acts to oppose sliding motion, even when it makes an object speed up. Learn how this works with a clear and simple example using a sliding disk and a moving block.

Showing relative motion of two cars from the sky!

Understand the forces of lift and drag (also called air resistance) and which way they point on different objects as they move through the air.

A video entitled "Two Way Tables" that covers the organization of two-way tables and the process of using relative frequencies to find percentages.

What is inside a Black Hole? A black hole is really not a celestial body like a planet or a star. There is really no substance there other than a severely curved space-time. It’a a region in space where matter is...

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