Cafe Science

Why do humans cook? Holidays are celebrated in many ways, but chances are they involve eating, and eating a LOT. Ever wonder why we cook our food? We do it because it tastes good, of course, and because our customs and traditions are built around it. But we also cook our food for some basic biological reasons, because of evolution. Some scientists think that figuring out how to cook actually MADE us human! If conversation gets a little dry around your holiday table, now you'll have some awesome science to share with everyone!

Oxygen forms about 21% of the air around us. In your body, oxygen forms a vital role in the production of energy in most cells. But if gases can only efficiently diffuse across tiny distances, how does oxygen reach the cells deep inside your body? Enda Butler tracks the surprisingly complex journey of oxygen through your body.

What really drives us to breathe? And how dangerous is it to hyperventilate and hold your breath?

There's a concept that's crucial to chemistry and physics. It helps explain why physical processes go one way and not the other: why ice melts, why cream spreads in coffee, why air leaks out of a punctured tire. It's entropy, and it's notoriously difficult to wrap our heads around. Jeff Phillips gives a crash course on entropy.

Is vocal fry bad for your voice? Does it hurt your chances of getting a job?

GPS services have made getting from point A to point B a lot easier, but what effects does this have on our brains?

How much blood can a human lose without dying, and how does the body replenish that blood once it's gone?

We've heard it. We get it. We know! Drink more water! But it's not just overplayed advice from fitness magazines and your mother. When we get dehydrated our bodies send out clear warning signs that we need to check our fluid levels. If that happens, it's important to do everything to get your hydration level back on track. Here are some of the symptoms associated with not drinking enough water...

Why are some people racist, but others are not?

The average person experiences dozens of individual itches each day. We've all experienced the annoyance of an inconvenient itch - but have you ever pondered why we itch in the first place? Is there actually an evolutionary purpose to the itch, or is it simply there to annoy us? Emma Bryce digs deep into the skin to find out.

Scientists are taking cancer patients' immune cells and engineering them to fight cancer. How does it work?

Clint Buffington has found 83 messages in bottles - and you could probably do it too. Vox's Zachary Crockett and Phil Edwards found out how.

Being able to sense time helps us do everything from waking and sleeping to knowing precisely when to catch a ball that's hurtling towards us. And we owe all these abilities to an interconnected system of timekeepers in our brains. But how do they work? Marco A. Sotomayor details how human bodies naturally tell time.

So maybe we can't outrun cheetahs or antelope, but humans are uniquely adapted for long distance running. What does science have to say about marathon running? To find out, (and because I was feeling a little crazy) I decided to run one!

Trace and Amy get their DNA test results, and we talk to an expert about how scientists actually get genetic information out of DNA.

The meter is the world's ultimate measure, but how did it become "the" meter? What is this measurement based on? The story of this revolution in measurement traces its roots to the French Revolution. Scientists decided that an equal and united people should have equal and united measures. So they sent a pair of young astronomers out to measure the world, and invent the meter. Little did they know they'd find nothing but war, deception, and strife along the way. As a result of this ill-fated mission, the meter carries an error that still persists today. Still think the metric system is so perfect?

See Through engine in slow motion.

Engineers at MIT have found a way to prevent hydrogels from dehydrating.

Building a perfect igloo takes cool science!

Thanks to Google Making and Science for supporting this series, and to Sean Carroll for collaborating on it!

1 tablespoon of olive oil destroys half an acre of waves on this lake. What The Physics?!