Why Are 96,000,000 Black Balls on This Reservoir?

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Why Are 96,000,000 Black Balls on This Reservoir? 5
I took a boat through 96 million black plastic balls on the Los Angeles reservoir to find out why they're there. The first time I heard about shade balls the claim was they reduce evaporation. But it turns out this isn't the reason they were introduced.

Huge thanks to LADWP for arranging this special tour for me. Next time let's put the GoPro on the submersible!

The balls are made of high density polyethylene (HDPE) which is less dense than water so they float on the surface of the reservoir even if they break apart. They are 10cm (4 inches) in diameter and contain about 210ml of water. So the main reason they are on the reservoir is to block sunlight from entering the water and triggering a chemical reaction that turns harmless bromide into carcinogenic bromate. This effect occurs with prolonged exposure to bromate so regulators insist that levels be kept below 10 microgram per liter on average over a 12 month period.

Special thanks to Patreon supporters:
Donal Botkin, Michael Krugman, Ron Neal, Stan Presolski, Terrance Shepherd, Penward Rhyme and everyone who provided feedback on an early draft of this video.

Thanks to:
Las Virgenes Reservoir for footage of initial shade ball dump
Euro-Matic for bird into jet-engine footage

Researched and Produced by Casey Rentz

Animations by Maria Raykova

And from Kevin MacLeod "Marty Gots a Plan"

This is an educational video about the science of water quality.

Download — Why Are 96,000,000 Black Balls on This Reservoir?

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💬 Comments on the video

Jesus christ, I finally watched it youtube are you happy?!

Author — polt


America: bro
Australia: mate

Author — Adam Pavese


Imagine replacing the balls, feel like that'd be a real pain

Author — Zac Catella


How long have they known that sunlight turns bromide into carcegenic bromate?

Author — Donna White


R.I.P to the bird that flew into a engine at 5:50

Author — Jamaal Piggue


Veritasium: It’s really rare to see 96 million of anything

Sand grains: Am I joke to you?

Author — Tiznado


takes a lot of balls to make a video like this



Who immediately thought can I jump in it...

Or is it only me.. ;-; lol

Author — RebelPlayz x


Why's there no one mentioning that they're edible?

Author — Random Dude


It's very rare to see 96 million of anything.

Pieces of that bird: Am I joke to you?

Author — Justin Natasmai


We all know their real purpose... to stop Mr. Incredible.

Author — LukeFili


How long does it take for them to breakdown?

Author — K T


You see that airplane suck up the bird.. Its insane😮 time 5:50

Author — Sergio Dumanlag


Soo basically you're driving around in a boat in my bath water..?

Author — Cali 760


So my drinking water had a motorboat on it

Author — BeCreative Gaming


"It's rare to see 96 million of anything"

*The 9 year old family would like a word*

Author — The Fizio


5:52 That bird...just died...

Thanos snapped on the bird

Author — JoshArch 22


"It's very rare to see 96 million of anything"
Pewdiepie's subcount: ...
YouTube music's subcount: ...
YouTube gaming's subcount:...
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T Series's subcount: ...

Author — Moce


"It's very rare for you to see 96 million of anything"

Pewdiepie: ...

Author — Matthew McColl


so keep it clean but drive boats in it huh? haha

Author — Bradley Sanders