Sciences · does it appeal?
Do you want to know how anyone found that out?
Fourteen questions about ordinary things — a cooker, a cut apple, a fever, the sea. None of them are about careers, and none of them need anything you have not been taught. What they have in common is that the interesting part is not the answer but how anybody could possibly have established it. If that sounds like a good afternoon, that tells you more than any amount of reading about what scientists do.
Answers are still being checked. 0 of 14 answers are verified and shown below. Verified here means the answer has been checked against a peer-reviewed source, a standard reference or a measurement anyone can repeat, and cites it. Some of these have a clean answer sitting in a textbook. Others are explanations rather than facts, where two accounts can both be partly right and the useful thing is what experiment would tell them apart — those stay questions however long this page is up. That is not the page being unfinished. It is the difference between something that has been measured and something that has been argued.
How anyone knows
How does anyone know how old the Earth is? Nobody was there.
It is not a guess and it is not a tradition. Somebody worked it out, and the method is more surprising than the number.
Answer being checked against the primary text before it goes up.
What answering it involves. Reading a past nobody watched. You cannot go back, so you find something in the present that could only have got this way at a rate you can measure, and you run the rate backwards. Finding a clock that nobody set and nobody wound is one of the most powerful moves there is, and it is how almost everything about deep time is known.
Someone in your family swears a home remedy cured them. What would it take to find out if it did?
Arguing about it goes nowhere, and they are not lying — they did take it and they did get better. The interesting question is what evidence would settle it either way.
Answer being checked against the primary text before it goes up.
What answering it involves. "Compared with what?" Almost every illness ends on its own, so getting better after doing something is nearly no evidence at all. Once you see that you need the people who did not take it, you have arrived unaided at the control group — and at why one convincing story is weaker evidence than a boring table.
How do we know what the Sun is made of, when nothing anyone owns has been near it?
No probe has brought back a sample and none ever will. We know anyway, in some detail, and the reason is sitting in a rainbow.
Answer being checked against the primary text before it goes up.
What answering it involves. Measuring by proxy. The only thing that reaches you from the Sun is light, so everything must be squeezed out of that — and light turns out to carry a fingerprint of what emitted it. Working out what a signal can tell you about a source you cannot reach is how most of astronomy and a good deal of chemistry is done.
Your body
Why does your body give itself a fever, when the fever is the part that makes you feel terrible?
It would be easy to assume the fever is the illness doing something to you. It is mostly you doing something to yourself, which raises an obvious question about why.
Answer being checked against the primary text before it goes up.
What answering it involves. Asking what a symptom is *for*. Separating the damage from the defence changes what you think treatment should even try to do, and it is the question that keeps returning in biology — is this thing broken, or is it working, and how would you tell?
Why does the doctor say finish the course when you feel completely fine on the third day?
You feel fine. The tablets are unpleasant. Everyone has been told the rule and almost nobody has been told the reason, which is a shame, because the reason is one of the most important ideas in biology.
Answer being checked against the primary text before it goes up.
What answering it involves. What is happening is happening to a population, not to you. Feeling better measures your body; the question is about the survivors of something you cannot see, and what you have just selected for. Once you can hold "the ones that are left are the ones that were hardest to kill" in your head, evolution stops being about dinosaurs and starts being about this week.
Identical twins start out identical. Why do they stop?
Same instructions, right down to the letter. Different fingerprints from birth, and more differences every year after that.
Answer being checked against the primary text before it goes up.
What answering it involves. The difference between the instructions and what happens while they are being carried out. It also turns a stale argument — is it nature or upbringing — into a question precise enough to actually test, which is usually the moment an argument becomes science.
The kitchen
Why does a pressure cooker cook faster? Is it the pressure, or something the pressure does?
The obvious answer is that the pressure squeezes the food. Most people have never been asked to say how, and trying to is where it gets interesting.
Answer being checked against the primary text before it goes up.
What answering it involves. Insisting on the step in the middle. Two things happening together is not an explanation, and the habit of asking "yes, but by what route" is what separates a mechanism from a correlation. It is also the difference between remembering that a cooker is faster and understanding why the same cooker behaves differently on a mountain.
Why does a cut apple go brown, and why does a squeeze of lemon stop it?
Two explanations sound equally reasonable — the lemon keeps the air off, or the lemon interferes with something in the apple. They cannot both be the main story.
Answer being checked against the primary text before it goes up.
What answering it involves. Two rival explanations that predict different experiments, which is the most useful thing a hypothesis can do. Sitting in your own kitchen you can design a test that would embarrass one of them, and designing that test is a better afternoon than being told the answer.
Why does soap get oil off your hands when water on its own will not?
You have done this every day of your life. The explanation is about the shape of something far too small to see, and it predicts several other things you have noticed and never connected.
Answer being checked against the primary text before it goes up.
What answering it involves. Explaining something you can watch by the structure of something you cannot. Moving between the scale of a hand and the scale of a molecule, and demanding that the story at one scale account for the behaviour at the other, is most of what chemistry is for.
The sky and the ground
The sky is blue in the afternoon and red in the evening. Is that one fact or two?
They look like two separate pieces of trivia and are usually taught as two. There is a version where they are the same sentence read twice.
Answer being checked against the primary text before it goes up.
What answering it involves. Economy. When one mechanism accounts for two things that looked unrelated, that is evidence for the mechanism rather than a tidy coincidence — and the pleasure of noticing it is, honestly, a large part of why people do this at all.
How much does a cloud weigh, and why is it still up there?
Work the weight out roughly before reading anything. The number is startling enough that most people redo it, and then the real question arrives.
Answer being checked against the primary text before it goes up.
What answering it involves. Estimation, followed by the moment the estimate contradicts what you can see out of the window. That contradiction is not a nuisance — it is the whole prompt, and resolving it forces you to ask what "heavy" even means for something spread out. Being willing to trust an arithmetic result that disagrees with your eyes is a learnable habit and not a common one.
The rivers running into the sea are not salty. So why is the sea?
Every child asks this. Almost every adult has stopped being able to answer it, and the answer has a second half that is better than the first.
Answer being checked against the primary text before it goes up.
What answering it involves. A rate so small it is unmeasurable in a lifetime, multiplied by a time so long it is unimaginable. And then the harder half — the water leaves and the salt does not, so what is going in has to be balanced against what is going out. Asking where a thing goes, as well as where it comes from, is how you stop believing in things that only accumulate.
Numbers and chance
A test that is right ninety-nine times out of a hundred says you have a rare disease. Should you believe it?
The intuitive answer is yes, obviously, and it can be badly wrong. Doctors get this one wrong in studies, which is either alarming or reassuring depending on your temperament.
Answer being checked against the primary text before it goes up.
What answering it involves. How rare the thing was before anyone tested for it changes what the result means, and nothing in the result itself tells you that. This is the single most useful idea on the page: a number can be entirely accurate and still not answer the question you asked it.
In a class of thirty, two people share a birthday. Is that a coincidence?
It feels like one. Work out how many pairs of people there are in a class of thirty before deciding.
Answer being checked against the primary text before it goes up.
What answering it involves. Counting the right thing. You are not asking whether someone shares *your* birthday — you are asking about every pair at once, and there are far more pairs than people. Restating a question until you can count what it is actually about is a move you will use on every survey, every claim about a coincidence, and every result anybody calls surprising.
What these have in common. Notice what these have in common. Not one of them can be settled by looking harder at the thing itself. Every single one turns into "what would I have to compare this against, and how would I know I was not fooling myself" — and that is not a preamble to the science. That is the science. The facts are what is left over afterwards, and they are the part school gives you first.
Whether it is you
| Worth a closer look if… | Probably not, if… |
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Am I already late?
Almost certainly not, and the answer depends on where you are standing rather than on how much you have done.
| If you are in | Then |
|---|---|
| Class 10 | Nothing to prepare, and one thing worth knowing. The science stream keeps every route in this field open; what closes doors is the choice inside it. Dropping Mathematics shuts the statistics and mathematics institutes and most of physics, and taking Applied Mathematics rather than Mathematics is where that happens to people who never meant it to — the same trap the engineering page names, and it catches science students more quietly because nobody warns them about it. |
| Class 11 | The year the entrance preparation is actually done, since the papers draw on both years. It is also the cheapest year to test whether you like the activity rather than the subject: do an experiment nobody set you and see whether the failure of it is interesting or merely annoying. That reaction is worth more than a mock score. |
| Class 12 | Not too late, and the shape of the decision here is unlike the other fields on this site. Most science degrees in this country have no entrance exam at all — they are decided on board marks or on a common university test — so the boards themselves carry more weight here than the entrances do. The research institutes are the exception and they have their own papers; check the exam pages for which of them collide with your boards. |
Books, none of them preparation
The cheapest way to find out whether any of this interests you. None of these are preparation material and none of them will help you pass anything. If you find you cannot put one of them down, that is a better signal than any mock test.
| Book | Author | Why this one |
|---|---|---|
| A Short History of Nearly Everything | Bill Bryson | The whole of science told as the story of how anybody found any of it out, including the arguments and the people who were wrong for decades. Pitched below Class 10 and readable in pieces, which is the point. |
| Bad Science | Ben Goldacre | How a claim goes wrong, and how to take one apart. If the questions above about the home remedy and the ninety-nine-per-cent test were the ones you liked, this is four hundred pages of exactly that. |
| Surely You're Joking, Mr. Feynman! | Richard Feynman | What doing science actually feels like from the inside, including the boredom, the showing off and the safe-cracking. The best available antidote to the documentary version of the job. |
| The Man Who Knew Infinity | Robert Kanigel | Ramanujan, from a clerk's desk in Madras to Cambridge and back. Read it for mathematics as something a person did rather than a syllabus, and for how badly the institutions of the time handled him. |
| The Immortal Life of Henrietta Lacks | Rebecca Skloot | Cell biology told through the woman whose cells were taken without her knowing. It belongs here because it insists that a result has a person at the other end of it, which is not how the subject is usually taught. |
| The Double Helix | James Watson | How one famous discovery was really made — competitively, hastily and not always decently. Worth reading for what it reveals about the author, and alongside what it leaves out about Rosalind Franklin. |
If that held your attention: where this field actually leads →
If you read these and found yourself wanting to know not just the answer but who worked it out and how they could be sure, that is worth paying attention to. If you read them and felt nothing, that is just as useful and it cost you four minutes. Neither reaction is the right one.