Physics

■ Two theoretical physicists are lost at the top of a mountain. Theoretical physicist No 1 pulls out a map and peruses it for a while. Then he turns to theoretical physicist No 2 and says: "Hey, I've figured it out. I know where we are."
"Where are we then?"
"Do you see that mountain over there?"
"Yes."
"Well… THAT'S where we are."

I heard this joke at a physics conference in Les Arcs (I was at the top of a mountain skiing at the time, so it was quite apt). It was explained to me that it was first told by a Nobel prize-winning experimental physicist by way of indicating how out-of-touch with the real world theoretical physicists can sometimes be.
Jeff Forshaw, professor of physics and astronomy, University of Manchester

■ An electron and a positron go into a bar.
Positron: "You're round."
Electron: "Are you sure?"
Positron: "I'm positive."
I think I heard this on Radio 4 after the publication of a record (small) measurement of the electron electric dipole moment – often explained as the roundness of the electron – by Jony Hudson et al in Nature 2011.
Joanna Haigh, professor of atmospheric physics, Imperial College, London

■ A group of wealthy investors wanted to be able to predict the outcome of a horse race. So they hired a group of biologists, a group of statisticians, and a group of physicists. Each group was given a year to research the issue. After one year, the groups all reported to the investors. The biologists said that they could genetically engineer an unbeatable racehorse, but it would take 200 years and $100bn. The statisticians reported next. They said that they could predict the outcome of any race, at a cost of $100m per race, and they would only be right 10% of the time. Finally, the physicists reported that they could also predict the outcome of any race, and that their process was cheap and simple. The investors listened eagerly to this proposal. The head physicist reported, "We have made several simplifying assumptions: first, let each horse be a perfect rolling sphere… "

This is really the joke form of "all models are wrong, some models are useful" and also sums up the sort of physics confidence that they can solve problems (i.e., by making the model solvable).
Ewan Birney, associate director, European Bioinformatics Institute

■ What is a physicist's favorite food? Fission chips.
Callum Roberts, professor in marine conservation, University of York

■ Why did Erwin Schrödinger, Paul Dirac and Wolfgang Pauli work in very small garages? Because they were quantum mechanics.
Lloyd Peck, professor, British Antarctic Survey

■ A friend who's in liquor production,
Has a still of astounding construction,
The alcohol boils,
Through old magnet coils,
He says that it's proof by induction.

I knew this limerick when I was at school. I've always loved comic poetry and I like the pun in it. And it is pretty geeky …
Helen Czerski, Institute of Sound and Vibration Research, Southampton

Biology

■ What does DNA stand for? National Dyslexia Association.

I first read this joke when I was an undergraduate as a mature student in 1990. I'd just come to terms with my own severe reading difficulties and neurophysiology was full of acronyms, which I always got mixed up. For example, the first time I heard about Adenosine Triphosphate it was abbreviated by the lecturer to ATP, which I heard as 80p. I had no clue what she was talking about every time she mentioned 80p. And another thing, how does Adenosine Triphosphate reduce to ATP? Where's the P?
Peter Lovatt, lecturer in psychology of dance, University of Hertfordshire

■ A new monk shows up at a monastery where the monks spend their time making copies of ancient books. The new monk goes to the basement of the monastery saying he wants to make copies of the originals rather than of others' copies so as to avoid duplicating errors they might have made. Several hours later the monks, wondering where their new friend is, find him crying in the basement. They ask him what is wrong and he says "the word is CELEBRATE, not CELIBATE!"

I first heard this maybe more than 10 years ago in conjunction with the general theme of "copying errors" or mutations in biology.
Mark Pagel, professor of biological sciences, University of Reading

■ A blowfly goes into a bar and asks: "Is that stool taken?"

No idea where I got this from!
Amoret Whitaker, entomologist, Natural History Museum

■ They have just found the gene for shyness. They would have found it earlier, but it was hiding behind two other genes.
Stuart Peirson, senior research scientist, Nuffield Laboratory of Ophthalmology

Maths

■ What does the 'B' in Benoit B Mandelbrot stand for? Benoit B Mandelbrot.

Mathematician Mandelbrot coined the word fractal – a form of geometric repetition.
Adam Rutherford, science writer and broadcaster

■ Why did the chicken cross the Möbius strip? To get to the other… eh? Hang on…

The most recent time I saw this joke was in Simon Singh's lovely book on maths in The Simpsons. I've heard it before though. I guess its origins are lost in the mists of time.
David Colquhoun, professor of pharmacology, University College London

■ A statistician is someone who tells you, when you've got your head in the fridge and your feet in the oven, that you're – on average - very comfortable.

This is a joke I was told a long time ago, probably as a high school student in India, trying to come to terms with the baffling ways of statistics. What I like about it is how it alerts you to the limitations of reductionist thinking but also makes you aware that we are unlikely to fall into such traps, even if we are not experts in the field.
Sunetra Gupta, professor of theoretical epidemiology, Oxford

■ At a party for functions, ex is at the bar looking despondent. The barman says: "Why don't you go and integrate?" To which ex replies: "It would not make any difference."

Heard by my daughter in a student bar in Oxford.
Jean-Paul Vincent, head of developmental biology, National Institute for Medical Research

■ There are 10 kinds of people in this world, those who understand binary, and those who don't.

I think this is just part of the cultural soup, so to speak. I don't remember hearing it myself until the mid-90s, when computers started getting in the way of everyone's lives!
Max Little, mathematician, Aston University

■ The floods had subsided, and Noah had safely landed his ark on Mount Sinai. "Go forth and multiply!" he told the animals, and so off they went two by two, and within a few weeks Noah heard the chatter of tiny monkeys, the snarl of tiny tigers and the stomp of baby elephants. Then he heard something he didn't recognize… a loud, revving buzz coming from the woods. He went in to find out what strange animal's offspring was making this noise, and discovered a pair of snakes wielding a chainsaw. "What on earth are you doing?" he cried. "You're destroying the trees!" "Well Noah," the snakes replied, "we tried to multiply as you bade us, but we're adders… so we have to use logs."
Alan Turnbull, National Physical Laboratory

■ A statistician gave birth to twins, but only had one of them baptized. She kept the other as a control.
David Spiegelhalter, professor of statistics, University of Cambridge

Chemistry

■ A chemistry teacher is recruited as a radio operator in the first world war. He soon becomes familiar with the military habit of abbreviating everything. As his unit comes under sustained attack, he is asked to urgently inform his HQ. "NaCl over NaOH! NaCl over NaOH!" he says. "NaCl over NaOH?" shouts his officer. "What do you mean?" "The base is under a salt!" came the reply.

I think I heard this when I was a student in the early 1980s.
Hugh Montgomery, professor of intensive care medicine, University College London

■ Sodium sodium sodium sodium sodium sodium sodium sodium Batman!

This is my current favourite. It comes from my daughter, who is a 17-year-old A-level science student.
Tony Ryan, professor of physical chemistry, University of Sheffield

■ A weed scientist goes into a shop. He asks: "Hey, you got any of that inhibitor of 3-phosphoshikimate-carboxyvinyl transferase? Shopkeeper: "You mean Roundup?" Scientist: "Yeah, that's it. I can never remember that dang name."

Made up by and first told by me.
John A Pickett, scientific leader of chemical ecology, Rothamsted Research

■ A mosquito was heard to complain
That chemists had poisoned her brain.
The cause of her sorrow
Was para-dichloro-
diphenyl-trichloroethane.

I first read this limerick in a science magazine when I was at school. I taught it to my baby sister, then to my children, and to my students. It's the only poem in their degree course.

Martyn Poliakoff, research professor of chemistry, University of Nottingham

Psychology

■ A psychoanalyst shows a patient an inkblot, and asks him what he sees. The patient says: "A man and woman making love." The psychoanalyst shows him a second inkblot, and the patient says: "That's also a man and woman making love." The psychoanalyst says: "You are obsessed with sex." The patient says: "What do you mean I am obsessed? You are the one with all the dirty pictures.''

I have no idea where I first heard this joke. I suspect when I was an undergraduate and was first taught about Freudian psychology.
Richard Wiseman, professor of public understanding of psychology, University of Hertfordshire

■ Psychiatrist to patient: "Don't worry. You're not deluded. You only think you are."

I heard this joke from my husband, my source of all good jokes. It is a variation of the type of joke I particularly like: a paradoxical twist of meaning. Here the surprising paradox is that you can at once be deluded and not deluded. This links to an aspect of my work that goes under the label "mentalising" and involves attributing thoughts to oneself and others. It's a mechanism that works beautifully, but the joke reveals how it can go wrong.
Uta Frith, professor in cognitive neuroscience, University College London

■ After sex, one behaviorist turned to another behaviorist and said, "That was great for you, but how was it for me?"

It's an oldie. I came across it in the late 1980s in a book by cognitive science legend Philip Johnson-Laird. Behaviorism was a movement in psychology that put the scientific observation of behavior above theorizing about unobservables like thoughts, feelings and beliefs. Johnson-Laird was one of my teachers at Cambridge, and he was using the joke to comment on the "cognitive revolution" that had overthrown behaviourism and shown that we can indeed have a rigorous science of cognitive states. Charles Fernyhough, professor of psychology at the University of Durham

Multidisciplinary

■ An interviewer approaches a variety of scientists, and asks them: "Is it true that all odd numbers are prime?" The mathematician rejects the conjecture. "One is prime, three is prime, five is prime, seven is prime, but nine is not. The conjecture is false." The physicist is less certain. "One is prime, three is prime, five is prime, seven is prime, but nine is not. Then again 11 is and so is 13. Up to the limits of measurement error, the conjecture appears to be true." The psychologist says: "One is prime, three is prime, five is prime, seven is prime, nine is not. Eleven is and so is 13. The result is statistically significant." The artist says: "One is prime, three is prime, five is prime, seven is prime, nine is prime. It's true, all odd numbers are prime!"
Gary Marcus, professor of psychology, New York University

■ What do scientists say when they go to the bar? Climate change scientists say: "Where's the ice?" Seismologists might ask for their drinks to be "shaken and not stirred". Microbiologists request just a small one. Neuroscientists ask for their drinks "to be spiked". Scientists studying the defective gubernaculum say: "Put mine in a highball", and finally, social scientists say: "I'd like something soft." When paying at the bar, geneticists say: "I think I have some change in my jeans." And at the end of the evening a shy benzene biochemist might say to his companion: "Please give me a ring."

Professor Ron Douglas of City University and I made these feeble jokes up after pondering the question: "What do scientists say at a cocktail party". Of course this idea can be developed – and may even stimulate your readers to come up with additional contributions.
Russell Foster, professor of circadian neuroscience, University of Oxford