science

Li's field

Li's field is a science 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 Li's field rather than just read about it. In short: Li's field (Chinese: 李氏力場) is a satirical conspiracy theory in Hong Kong over the existence of a force field that repels tropical cyclones from the city. Background The "Li" in Li's field refers to local business tycoon Li Ka-shing, the implied developer of the field.

Key takeaways

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

Reference excerpt

Li's field (Chinese: 李氏力場) is a satirical conspiracy theory in Hong Kong over the existence of a force field that repels tropical cyclones from the city.

Background The "Li" in Li's field refers to local business tycoon Li Ka-shing, the implied developer of the field. The basis of Li's field rests on the way Hong Kong's government is organized. The city's Commerce and Economic Development Bureau oversees the Hong Kong Observatory, and that has led to speculations the Observatory bases its issuance of tropical cyclone warning signals on economic reasoning, instead of scientific reasoning. In Hong Kong, schools above kindergarten level are shut down when Tropical Cyclone Signal Number 8 is issued (kindergarten classes are suspended when Signal Number 3 is issued), and all non-essential staff at a workplace are sent home. Some believe businesses have pressured the Observatory into avoiding the issuance of Typhoon Signal Number 8, in an effort to avoid economic losses. In response, former Observatory Chief Lee Boon Ying told reporters in 2010 the Observatory has always put the safety of Hong Kong residents as its first priority, and is not swayed by business or economic concerns.

Examples From 2005 to 2006, and again in 2010, the Observatory did not issue a single tropical cyclone warning above Number 3.

Typhoon Prapiroon In 2006, Typhoon Prapiroon brought gale to storm winds (63-117 km/h, Beaufort scale force 8–11) to Hong Kong, fulfilling the requirements for the No.8 Gale or Storm signal. The storm overturned containers, uprooted trees, and caused many flight delays at the airport, but the Observatory did not issue Signal Number 8, remaining at the lower level Signal Number 3. Observatory Chief Lam Chiu-ying later said the decision was based on the fact that wind speeds in Kai Tak, near the Victoria Harbour, did not reach the level required for issuing Signal Number 8. Nevertheless, humorous speculation arose that Li Ka-shing was behind the decision, in an effort to maximize productivity from his workers and prop up the economy.

Scientific reason

Media reports in 2010, citing research by the Observatory, revealed the reason behind the fewer occurrences of Signal Number 8. It is believed that an ocean temperature difference between the South China Sea and the Pacific Ocean provides the explanation.

Cultural references Li's force field has been mentioned in local cultural media, and has been the subject of many Internet memes.

"Gambling wall" in Macau A similar urban legend spread in Macau after Tropical Storm Nida (2016), when the Macao Meteorological and Geophysical Bureau (SMG) only issued a No. 3 typhoon signal, despite it reaching the standards of a No. 8. Some residents believed the SMG did so because the issuance of a No. 8 signal would affect the opening hours of casinos (which represent Macau's largest industry), leading them to joke that there was a "賭牆" (literally: "gambling wall", homophonous in Cantonese with 賭場 "casino") which protected Macau from typhoons, much like Li's field.

See also Bielefeld conspiracy Birds Aren't Real Hong Kong tropical cyclone warning signals

References

Illustrations

Worked examples

Example 1 — a first encounter with Li's field

Start with the simplest possible case. Write down what Li's field claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Li's field 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 Li's field 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 Li's field

In research: Li's field appears in science 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 Li's field 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: Li's field is common in secondary-school and first-year university syllabi. It links to neighbouring topics Conspiracy theories in China, Culture of Hong Kong, Humour, so understanding it makes those chapters shorter.
In everyday life: Look for Li's field 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Li's field in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Li's field 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 Li's field out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Li's field in simple terms?

Li's field (Chinese: 李氏力場) is a satirical conspiracy theory in Hong Kong over the existence of a force field that repels tropical cyclones from the city. Background The "Li" in Li's field refers to local business tycoon Li Ka-shing, the implied developer of the field.

Why does Li's field matter?

Because it connects several science 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 Li's field?

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 Li's field.