engineering

Shade ball

Shade ball is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Shade ball rather than just read about it. In short: A shade ball is a small plastic sphere floated on top of a reservoir for environmental reasons, including to slow evaporation and prevent sunlight from causing reactions among chemical compounds present in the water. Also known as bird balls, they were developed initially to prevent birds from landing in bodies of water.

Key takeaways

Shade ball belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Shade ball to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Shade ball from memory before moving on to harder problems.

Reference excerpt

A shade ball is a small plastic sphere floated on top of a reservoir for environmental reasons, including to slow evaporation and prevent sunlight from causing reactions among chemical compounds present in the water. Also known as bird balls, they were developed initially to prevent birds from landing in bodies of water.

History Shade balls were originally known as bird balls, as they were developed initially to prevent birds from landing on toxic tailing ponds produced by mining operations. They have also been used by airports to prevent birds from being attracted to nearby drainage ponds, thus reducing collisions with planes.

Usage by LADWP

Starting in mid-2009, the Los Angeles Department of Water and Power (LADWP) put about 400,000 balls in the Ivanhoe reservoir with the main objective of preventing the formation of a carcinogenic chemical, bromate, which forms when sunlight interacts with naturally occurring bromine and the chlorine added to prevent algae growth. In the original release by the LADWP, there is no mention of water conservation as an objective and the project was planned for a five-year life span, until a Griffith Park project was completed. The reduction in evaporation led to an estimated savings of about 1.1 billion L (290 million US gal) of water in one year. In 2014 and 2015, the LADWP put 96 million shade balls onto its largest reservoir (Las Virgenes) in response to the United States Environmental Protection Agency's surface water treatment rule, which requires large reservoirs of treated water to be covered. The LADWP says that in addition to reducing evaporation, they also reduce UV radiation by-products and algae growth. The balls saved 1.7 million cubic metres of water from evaporating during their deployment from August 2015 to March 2017. However, they required 2.9 million cubic metres of water in their manufacture. Nevertheless, the balls have a lifespan of ten years, and the plastic may be reused after that.

Construction

The shade balls used in the Los Angeles project are made of high-density polyethylene (HDPE) with carbon black additive to make the balls opaque and protect the plastic from ultraviolet radiation. Adding carbon black also prevents the formation of bromate, a suspected human carcinogen. They are about 4 inches (10 cm) in diameter, and are partially filled with water to avoid being blown by wind. HDPE plastic is commonly used for food and beverage containers as well as water distribution pipes.

References

External links

Video of 2014 Shade Ball Deployment on YouTube Video "Why Are 96,000,000 Black Balls on This Reservoir?" on YouTube

Illustrations

Worked examples

Example 1 — a first encounter with Shade ball

Start with the simplest possible case. Write down what Shade ball claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Shade ball before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Shade ball ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Shade ball

In research: Shade ball appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Shade ball in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Shade ball is common in secondary-school and first-year university syllabi. It links to neighbouring topics Balls, Reservoirs, Water supply infrastructure, so understanding it makes those chapters shorter.
In everyday life: Look for Shade ball outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Shade ball in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Shade ball means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Shade ball out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Shade ball in simple terms?

Why does Shade ball matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Shade ball?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Shade ball.