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Reactions
How Do We Know How Old the Earth Is?
Season 4
Episode 31
Since there’s no “established in” plaque stuck in a cliff somewhere, geologists deduced the age of the Earth thanks to a handful of radioactive elements. With radiometric dating, scientists can put an age on really old rocks — and even good old Mother Earth. For the 30th anniversary of National Chemistry Week, this edition of Reactions describes how scientists date rocks.
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9:53
Scientific fraud rocked the Alzheimer’s research community. Did it help point to a cure?

12:54
Alex Dainis explores whether or not your milk needs to be pasteurized. Yes, it really does.

14:04
George tests a revolutionary new way to stick stuff together.

12:02
Sometimes the difference between life-saving drug and deadly side effect is chirality.

17:23
What happens when you eat morel mushrooms.

10:31
WARNING: this video contains incredible macro footage of supercooled water droplets nucleating ice.

13:12
Let’s dive into the science behind ocean alkalinization!

16:56
Discover why curdled milk is the key to the best cocktail you’ll ever taste.

10:13
Scientists are finding the building blocks of carbon ring structures… out in space!

12:00
George becomes a pyromaniac to figure out if ammonia is the fuel of the future.

13:06
Why Alex is terrified of antibiotic resistance, and what chemists are doing about it

9:01
Are liquid, virtually fireproof, recyclable batteries the future of grid-scale storage?