Truth Checks on The VikiD Truth

Does every AI email drink a bottle of water?

Sun, 25 Oct 2026 04:20:00 +0400

Where the claim comes from

In September 2024 The Washington Post, working with researchers at UC Riverside, published “A bottle of water per email”. It said a 100-word email written by GPT-4 needs 519 millilitres of water, a little more than a standard bottle. The figure spread everywhere, and it still turns up in arguments about AI.

What’s actually true

It’s a model, not a measurement. The method comes from the paper Making AI Less “Thirsty”. That paper estimated GPT-3 used about 500 ml of water for every 10 to 50 medium-length responses, depending on where and when the model runs. It counts water evaporated to cool the data centre and water used to generate the electricity it draws.
Most of that water isn’t in the data centre. Critics who went through the method, including writer Andy Masley in correspondence with the paper’s lead researcher Shaolei Ren, found that most of the bottle is water used by off-site power plants. That includes evaporation from hydroelectric reservoirs. Ren later told the Deseret News that the figure shouldn’t be treated as an accurate measure of today’s AI. In his words: “We cannot just use a number from two years ago to describe today’s system.”
Newer measurements are far lower. In August 2025 Google published its own figures: a median Gemini Apps text prompt used 0.26 ml of water and 0.24 Wh of energy, “about five drops”. In June 2025 OpenAI’s Sam Altman wrote that an average ChatGPT query uses about 0.000085 gallons, roughly a fifteenth of a teaspoon (about 0.3 ml). Both are company-reported figures, not independent audits.
The total is still real. Billions of prompts a day add up. Training runs and new data centres also draw heavily on local water and power, especially in hot, dry places like the Gulf.

The truth

The truth: The bottle came from stacking worst-case assumptions about a 2020-era system, then running the result through a headline. Each prompt is closer to a few drops. The real story is the total: how many data centres get built, where, and what power and cooling they use. Ask about that, not about your email.

Is gold a hedge against inflation?

Sun, 25 Oct 2026 04:15:00 +0400

Where the claim comes from

It’s probably the most repeated line in investing. Money printers go brrr, paper loses value, gold doesn’t. You hear it every time prices rise, and gold is on my own Markets board every day for exactly that reason: people watch it as a fear gauge.

What’s actually true

The most cited study is The Golden Dilemma by Claude Erb and Campbell Harvey of Duke University. It was an NBER working paper in 2013, later published in the Financial Analysts Journal. They tested the popular stories about gold one by one.

Sell in May and go away?

Sun, 25 Oct 2026 04:10:00 +0400

Where the claim comes from

It’s an old saying in the European financial press, with an ending about coming back for the St Leger horse race in September. In the US it’s called the “Halloween indicator”: be in stocks from 31 October to 30 April and out for the other half of the year. Most market sayings are noise. This one turned out to be harder to dismiss.

What’s actually true

The pattern is real in the data. In 2002 Sven Bouman and Ben Jacobsen tested it in the American Economic Review. In their words, they found “this inherited wisdom to be true in 36 of the 37 developed and emerging markets studied”. It was especially strong in Europe, and in the UK they traced it back to 1694. They found no convincing explanation in risk, the January effect or links between markets.
It kept working after it was published. Most anomalies fade once academics publish them. A 2013 Financial Analysts Journal paper by Andrade, Chhaochharia and Fuerst tested the same 37 markets out of sample, from 1998 to 2012. They found November–April returns still averaged about 10 percentage points higher than May–October.
But “lower” isn’t “negative”. Bouman and Jacobsen found May–October returns “close to zero in many countries”, not reliably below zero. Sitting in cash means giving up whatever the summer does return, and it brings trading costs and, in many countries, taxes. A seasonal average says nothing about whether this summer will be a bad one.

The truth

The truth: This is one of the rare pieces of market folklore with serious evidence behind it. As a fact about averages, it holds up. As a trading rule, it’s a bet on an average, made once a year with real costs. Respect the pattern, but don’t treat it as a law.

Is copper the best electrical conductor?

Sun, 25 Oct 2026 04:05:00 +0400

Where the claim comes from

Copper is everywhere electricity goes: house wiring, motors, transformers, data centres. It’s also one of the metals I track every day on the Markets board, because cable makers live and die by its price. So it’s easy to assume it must be the best conductor there is.

What’s actually true

Copper is the yardstick. In 1913 the International Electrotechnical Commission adopted the International Annealed Copper Standard (IACS). Annealed copper at 20 °C is defined as 100% IACS (58 MS/m), and every other metal is rated against it. Modern high-conductivity copper routinely reaches 101–102% IACS.
Silver beats it. Pure silver is about 106% IACS, the most conductive metal. It isn’t used for ordinary wiring because it’s expensive and mechanically weak, so it stays in specialist uses like contacts.
Gold is worse, not better. Gold is about 70% IACS. It’s used on connectors because it doesn’t corrode, not because it conducts well.
Aluminium is the other big one. Pure aluminium is about 61% IACS, but it’s much lighter and cheaper per amp carried. That’s why overhead transmission lines are mostly aluminium conductor, while copper dominates cables, buildings and machines.

The truth

The truth: Copper isn’t the best conductor. It’s the best conductor you can afford by the tonne, and that’s why its price is a barometer for the whole electrical industry. When copper gets expensive, engineers reach for aluminium, never for silver.

Do we only use 10% of our brains?

Sun, 25 Oct 2026 04:00:00 +0400

Where the claim comes from

The film version is a pill that unlocks the “other 90%” and gives you superpowers. Nobody knows exactly where the myth started. It’s often linked to the psychologist William James, who wrote that “we are making use of only a small part of our possible mental and physical resources”, and it’s sometimes attributed to Einstein. James was making a point about potential, not anatomy.

What’s actually true

From Scientific American’s explainer, which quotes neurologists at Johns Hopkins and the Mayo Clinic: