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\nWhy Are 96,000,000 Black Balls on This Reservoir?\n

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\n\nPublisher:\n\nVeritasium\n\n\n
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\nI 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...\nI 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. 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.\n
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Resource Details

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Curator Rating
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Educator Rating
Not yet Rated
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Media Length
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12:06
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Grade
9th - Higher Ed
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Subjects
Science
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Media Type
Instructional Videos
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Source:
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\nVeritasium\n\n
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Date
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2019
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Language
English
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Audiences
For Teacher Use
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Usage Permissions
Fine Print: Educational Use
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Concepts

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chlorine, cost, sunlight, los angeles, water, water quality, algae, drinking water, balls, birds, evaporation, plastic
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Additional Tags

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ladwp, los angelus, la, coming, black balls, heard, kind, veritasium, physics, black, ball pit, bromate, science, carcinogen, safe, fill, problem, la reservoir, water supply, shade balls, shade, carcinogenic, material, difficult, make, reduce evaporation, life, reservoir, bromide, nuts, reason, open reservoir, hard, remove
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Classroom Considerations

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Best For: Explaining a topic
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