Guess The Weight has hundreds of items, from fleas to skyscrapers. Some are easy. Others catch out almost everyone, because our intuition about weight is built on things we can lift. Here are twelve of the most surprising, grouped from tiny to enormous, with the reasoning that makes each one click.
1. A honey bee: about 0.1 g
You would need around ten thousand bees to make a kilogram. A worker bee can still carry a load of nectar or pollen that is a large fraction of its own body weight back to the hive.
2. A bee hummingbird: about 1.6 g
The smallest bird in the world, found in Cuba, weighs less than a single sheet of A4 printer paper (about 5 g). Its eggs are roughly the size of a coffee bean.
3. A credit card and a sheet of paper: both about 5 g
Two objects that feel completely different in the hand weigh the same. Thickness fools us: a card is stiff and solid, while a sheet of paper is large and floppy, but the total amount of material is similar.
4. A golf ball vs. a tennis ball: 46 g vs. 58 g
The tennis ball is much bigger, yet only slightly heavier, because it is hollow and filled with air. The golf ball is small but solid all the way through. Official rules cap a golf ball at 45.93 g.
5. A high-end graphics card: over 2 kg
Modern gaming graphics cards are mostly metal cooling fins and heat pipes. The RTX 4090 Founders Edition weighs about 2.2 kg, heavier than many laptops.
6. An Oscar statuette: 3.85 kg
It is only about 34 cm tall, but the statuette is solid bronze plated in gold. Winners often comment on how surprisingly heavy it is when they lift it on stage.
7. A Formula One car: about 800 kg
Including the driver, recent rules have set the minimum weight of an F1 car at roughly 770 to 800 kg, less than a typical compact family car (around 1,200 kg). Teams build them as light as possible and then add ballast to reach the minimum.
8. A giraffe: about 1,200 kg
A giraffe looks slim, but an adult male can stand over 5 metres tall and weighs as much as a car. Its neck alone can weigh more than an adult human.
9. A blue whale: about 150,000 kg
The largest animal known to have ever lived weighs as much as roughly 25 African elephants. A blue whale's heart alone weighs around 180 kg, about as much as two adult humans.
10. An average cumulus cloud: about 500 tonnes
This is the one nobody gets right. A fluffy fair-weather cloud about a kilometre across holds roughly half a gram of water in every cubic metre of air. Spread over a billion cubic metres, that adds up to around 500 tonnes, about the weight of eighty elephants. It floats because the droplets are tiny and spread out, and rising air keeps them aloft.
11. The International Space Station: about 420 tonnes
The ISS was assembled piece by piece over more than a decade from dozens of launches. On Earth it would weigh about as much as a fully loaded jumbo jet.
12. The Eiffel Tower: about 10,100 tonnes
That figure includes everything: the iron structure (about 7,300 tonnes), lifts, shops and fittings. For something 330 metres tall it is remarkably light. If you melted down its iron and spread it over the square base of the tower, the layer would be only about 6 cm thick.
Almost every surprise comes from the same mistake: judging weight by size instead of by size and density. Hollow things (tennis balls, the Eiffel Tower's lattice) are lighter than they look, and solid metal things (golf balls, graphics cards, Oscars) are heavier. Clouds are the extreme case: enormous volume, tiny density, and still a huge total.
Test yourself in Guess The Weight, or read How to Get Better at Estimation Games for techniques that work across every game.