# WATCH: Don't Be Fooled by These Common Physics Misconceptions

Time to set that high school physics straight.

BEC CREW
9 JUN 2016

We're all pretty used to loling about Flat-Earthers and their crazy antics by now, but the sad truth is that, instead of wasting our time trying to convince conspiracy theorists with, you know, the facts, maybe we should be looking inward, and clearing up some of our own problems with miscommunication in science.

Case in point: gravity. I'm sorry to tell you, but if you don't have a college-level education in physics, gravity probably isn't what you think it is.

As the MinutePhysics video above explains, most people's understanding of gravity is actually pretty skewed. In high school, you probably learned that objects attract each other based on their mass, and seeing as light particles - or photons - don't have mass, it makes sense that light cannot be affected by gravity, right?

Wrong, because the source of gravity isn't mass at all, it's energy + momentum.

Regular matter, such as the atoms that make up our bodies, our homes, and our planet, has energy and momentum, but so does light. This means that not only does light get affected by gravity, from say a planet or a black hole, but it also exerts an influence on these things in return. It's a very, very tiny influence, but an influence all the same.

The upshot of all of this? Newton's law of gravitation has got nothing on Einstein's theory of general relativity

Next up, let's talk about special relativity. Say you've got a sheep on a train running at 2 km/h relative to the train, and the train was travelling at 2 km/h relative to the ground. It makes perfect sense to say that the sheep is travelling at 4 km/h relative to the ground, right? Nope, we wish it were that simple.

As Henry explains, experimental evidence has shown that velocities don't simply add together to give an accurate total. It's close, but not exact, which is the problem with oversimplifying things to make them easier to understand - simple explanations lead to not entirely accurate answers.

And that brings us back to that 'flat-Earth' problem, which you can also use the principles of special relativity to disprove. I'll let the MinutePhysics video above explain that one, and while you're at it, watch the episode below to find out why there is no fourth dimension:

But don't stop exercising!

1 hour ago

He's just trolling us now.

2 hours ago

It should provide "near-normal urinary and sexual functions".

3 hours ago
4 hours ago
20 hours ago

It's not just the double helix!

13 hours ago

*cue immature giggling*

13 hours ago