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Why It Is What Time It Is (The History of Time)

How did we come up with our system of telling time? Why do we divide the day into 24 hours of 60 minutes each, and put 60 seconds in each minute? Where does the definition of a second come from? And who decides what clock shows the correct time? There’s clearly a lot of questions when it comes to time.
Season 5 Episode 36 Length 05:54 Premiere: 10/17/17

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Specials

Season 5 Episodes

Why Is Blue So Rare In Nature?
S5 E45 Length 07:39 Premiere Date 01/09/18

How Atom Bombs Can Uncover Forged Art
S5 E44 Length 05:06 Premiere Date 01/02/18

Why Do You Love Your Family?
S5 E43 Length 06:56 Premiere Date 12/20/17

20 Million Year-Old Spider!! Unweaving Spider Silk 🕷
S5 E42 Length 07:14 Premiere Date 12/12/17

Inside an Ice Cave! - Nature's Most Beautiful Blue
S5 E41 Length 05:45 Premiere Date 11/28/17

The Romantic Lure of Moonlight
S5 E40 Length 03:46 Premiere Date 11/15/17

Asteroid Mining: Our Ticket To Living Off Earth?
S5 E39 Length 05:17 Premiere Date 11/07/17

Should You Eat Everyday?
S5 E38 Length 04:38 Premiere Date 11/01/17

The Cheerios Effect
S5 E37 Length 05:08 Premiere Date 10/25/17

Why It Is What Time It Is (The History of Time)
S5 E36 Length 05:54 Premiere Date 10/17/17

Doomsday Machines
S5 E35 Length 05:35 Premiere Date 10/03/17

Why Is The Universe So Empty? (ft. PHD Comics!)
S5 E34 Length 04:04 Premiere Date 09/26/17

Do You Really Have Two Brains?
S5 E33 Length 04:20 Premiere Date 09/19/17

Why Do Disney Princesses All Look Like Babies?
S5 E32 Length 06:04 Premiere Date 08/22/18

Putting Hurricane Harvey In Perspective
S5 E32 Length 03:58 Premiere Date 09/15/17

DNA Doesn’t Look Like What You Think!
S5 E31 Length 05:18 Premiere Date 09/05/17

3 Incredible Examples of Evolution Hidden In Your Body
S5 E31 Length 06:58 Premiere Date 07/24/18

How Poop Shapes the World
S5 E30 Length 03:34 Premiere Date 08/29/17

The Only Animal That Weeps
S5 E30 Length 04:24 Premiere Date 07/24/18

When Is It Winter On Other Planets?
S5 E29 Length 05:00 Premiere Date 08/25/17

The Surprising Reason We Eat Spicy Food
S5 E29 Length 05:38 Premiere Date 07/24/18

Your Climate Conscience - feat. Al Gore
S5 E28 Length 05:21 Premiere Date 08/08/17

It's Okay to Fart
S5 E28 Length 05:07 Premiere Date 07/24/18

Why Nature Loves Hexagons (featuring Infinite Series!)
S5 E27 Length 05:58 Premiere Date 08/03/17

Which Life Form REALLY Dominates Earth?
S5 E27 Length 06:23 Premiere Date 07/24/18

How Do Glaciers Move?
S5 E26 Length 06:30 Premiere Date 07/25/17

What’s The Hottest Hot and Coldest Cold?
S5 E26 Length 05:11 Premiere Date 07/24/18

Beavers: The Smartest Things in Fur Pants
S5 E25 Length 04:42 Premiere Date 07/19/17

How Evolution Turned A Possum Into A Wolf
S5 E25 Length 07:02 Premiere Date 07/24/18

Orchid Mantis: Looks That Kill
S5 E24 Length 03:44 Premiere Date 07/11/17

The Cosmic Origins of Earth's Water
S5 E24 Length 04:14 Premiere Date 07/24/18

The Deadpool Salamander That Can Regrow Limbs
S5 E23 Length 07:16 Premiere Date 07/24/18

Why Do Fireflies Have Blinky Bottoms?
S5 E23 Length 04:22 Premiere Date 07/03/17

Why Do We Itch?
S5 E22 Length 04:57 Premiere Date 06/25/18

How The Pyramids Were Built (Pyramid Science Part 2)
S5 E22 Length 05:41 Premiere Date 06/30/17

What If You Never Forgot Anything?
S5 E21 Length 08:22 Premiere Date 05/07/18

Is Space A Thing?
S5 E21 Length 07:14 Premiere Date 06/20/17

97% of Climate Scientists Really Do Agree
S5 E20 Length 05:39 Premiere Date 05/07/18

How Ingenious Animals Have Engineered Air Conditioning
S5 E20 Length 03:54 Premiere Date 06/13/17

ЩΉӨ BЦIᄂƬ ƬΉΣ PYЯΛMIDƧ - Who Built The Pyramids
S5 E19 Length 04:47 Premiere Date 06/02/17

Can You Bend Light Like This?
S5 E18 Length 08:04 Premiere Date 04/11/18

De-Extinction: A Mammoth Undertaking
S5 E18 Length 04:42 Premiere Date 05/23/17

Could You Be Immune To Everything?
S5 E17 Length 06:16 Premiere Date 03/09/18

CRISPR and the Future of Human Evolution
S5 E17 Length 05:58 Premiere Date 05/17/17

Are We All Related?
S5 E16 Length 06:06 Premiere Date 05/09/17

Why Are There As Many Males As Females?
S5 E16 Length 05:20 Premiere Date 02/27/18

Why Does Hair Grow The Way It Does?
S5 E15 Length 04:18 Premiere Date 05/02/17

Defusing the Population Bomb
S5 E15 Length 05:51 Premiere Date 02/27/18

Tuatara All the Way Down
S5 E14 Length 07:55 Premiere Date 02/27/18

Why Are We The Only Humans Left?
S5 E14 Length 06:09 Premiere Date 04/25/17

Where Did Humans Come From?
S5 E13 Length 06:18 Premiere Date 04/18/17

Dogs and Humans: A 30,000-Year Friendship (ft. MinuteEarth)
S5 E12 Length 03:36 Premiere Date 04/12/17

Why I ❤ PBS
S5 E11 Length 02:32 Premiere Date 04/10/17

How Much Plastic is in the Ocean?
S5 E10 Length 04:43 Premiere Date 03/28/17

Illuminating the Universe: The History of Light
S5 E9 Length 05:51 Premiere Date 03/21/17

What is Luck?
S5 E8 Length 05:10 Premiere Date 03/17/17

How Do We Know Plate Tectonics Is Real?
S5 E7 Length 04:03 Premiere Date 03/07/17

How the Meter Became The Meter
S5 E6 Length 06:02 Premiere Date 02/28/17

How the Toilet Changed History
S5 E5 Length 05:43 Premiere Date 02/14/17

Relationship Advice from the Animal Kingdom
S5 E4 Length 05:18 Premiere Date 02/08/17

The Superb Owl!
S5 E3 Length 04:10 Premiere Date 01/31/17

How Many Species Are There?
S5 E2 Length 04:16 Premiere Date 01/24/17

Is This A NEW SPECIES?!
S5 E1 Length 08:06 Premiere Date 01/17/17

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