Why does mint feel cold and chiles feel hot?
So, the way we experience…pretty much everything is via proteins and ion channels. Very basically…there are proteins that are designed to sense certain things….the presence of sugar, whether they’ve been struck by light, the concentration of CO2 in the blood. When they sense those things, they open an ion channel changing the electrical charge of the cell, which then get transferred through the nervous system to the brain where that area of the brain is like “Cool…we’ve got sugar…or light…or too much CO2 in the blood.”
Well, sometimes these proteins can be fooled. A chemical will, just by chance (or by natural selection) be able to bind with that protein and cause that whole cascade to occur without the real stimulus. This is what happens with menthol in mint and capsaicin in peppers. Those chemicals bind to the cold / hot receptors respectively, fooling your body into thinking that something cold / hot is happening in your mouth. Pretty cool.
-Hank
Check out this adorably fantastic thankstank art that was sent in by SciShow viewers Tori and Mallory! It features the names of the fishy inhabitants of our office tank, as well as a corndog-lured anglerfish, Mount McDoobly-Doo the rock, and Papa the tree. Thanks, you two!

Check out this adorably fantastic thankstank art that was sent in by SciShow viewers Tori and Mallory! It features the names of the fishy inhabitants of our office tank, as well as a corndog-lured anglerfish, Mount McDoobly-Doo the rock, and Papa the tree. Thanks, you two!

Why Do Dogs Eat Grass?

Why do dogs eat grass? A look at your pup’s wild relatives may give you a sense of what dogs’ diets are really like.

Are Blue Eyes Endangered?

SciShow explains the genetics — and physics — behind why blue eyes are blue, and what the future may be for the trait. Spoiler alert: Blue eyes aren’t really blue! SciShow explains!

What Really Killed the Dinosaurs?

What wiped out the dinosaurs? Most of us were taught it was a killer asteroid — which is true. But it turns out there was more than one disaster movie playing at the cineplex that was Earth 66 million years ago.

We’re bad judges, better teachers, and video games are pretty good for us!

Humans judge each other within 33 milliseconds of seeing each other! We learn better if we think we have to teach someone else, and video games are good for us! 

Did you know that we’ve got 100 freshly-signed copies of SciShow: The Apocalypse Collection on DVD?! These DVDs feature 8 SciShow episodes, lots of outtakes, 25 minutes’ worth of interviews with the SciShow crew, and a big ol’ signature by the one and only Hank Green. 

You can pick up your own copy (while supporting SciShow) right now on Subbable!

Comet Chase & Molten Moons

In this episode of SciShow Space News, Hank details the work of the European Space Agency’s Rosetta spacecraft. He also explains the new discoveries of Jupiter’s moon Io.

I'm confused on the nature of gravity in space. Why is it called "zero gravity"?

First, there’s gravity everywhere. We’ve got a whole episode on it. But we also have this unit of force called the g-force, sometimes abbreviated as G (though this isn’t a technical SI unit.) One G is the amount of force we all experience because of the Earth’s gravity all the time. Two Gs would be double that…we can experience this much force if we’re accelerating away from earth or on a planet two-times more massive than earth (but the same size.) Likewise, if we are in constant freefall (as astronauts are when they orbit the earth) they will experience no Gs at all.  We would call that “Zero G” which is not, oddly enough, the same thing as “zero gravity.” Gravity is a force…not amount of force, and just because you are under the influence of gravity (as everything in the universe is (as far as we know)) does not mean you are feeling “G forces.”

-Hank

Scishow tie?

SciShow tie!

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