Physicists consider that they have "seen" a particle when their detectors send an electronic signal and a spot appears on their computer screen. The American artist Julie Peasley has gone much further than that. She has started sewing soft toys so that we can not just see what particles look like but even play with them.
Julie, who is based in Los Angeles, has been passionate about physics since she was a teenager. She eventually opted for art studies but she never stopped reading physics books and her library at home is full of all sorts of scientific publications and even audio books to accompany her long hours spent sewing toys. "I have always been interested in physics and cosmology," Julie explains. "A year and a half ago I went to a craft fair and I saw that people were making little soft creatures of various things and it just seemed to me that particles I was studying had personality. So, why not turn them into little characters!"
She has no doubts that particles have strong personalities, "because this is what is needed to make up the whole universe". At first, says Julie, "my plushies weren't smiling, they were just a face. Later on, I realized that I wanted them to all be happy and to appear like they are having fun – except for the neutron, which insists on remaining neutral."
Julie had little sewing experience to start with but she decided to give it a go and soon she was selling her wares on the web. Less than three months later, in May 2008, she quit her job as a graphic designer and started designing and making the particle zoo full time. Physics World magazine soon noticed her web site and then other scientific publications and blogs took over and spread the word. "Initially, I did not have the idea that this could be as popular as it is today," says Julie. "Now I think it has reached the point where people who are interested in physics, scientists, teachers, know about it."
During the week of the LHC start-up in September 2008, Julie experienced a big spike in her sales to the point that she had to work more than 12 hours a day to satisfy the requests. "During a slow period I make about 5–10 particle plushies per day but I can make 30–40 a day when it gets really busy," she explains. She has also tried to mass-produce her particles in China "but I only did it for the electron because mass-producing the whole zoo would require an investment of a lot of money up front and I don't have enough business yet".
Julie's sales imply that the public seems to appreciate the theoretical, yet undiscovered, particles more than the others. Despite the big publicity that antimatter is receiving following the release of the Hollywood blockbuster Angels & Demons, "antimatter doesn't sell particularly well. The Higgs is the real top-seller and in second place is dark matter. The charm quarks are very popular at Valentine's day because they are pink and have a rose." All particles are cute and full of positive energy. Her favourites are the proton and the photon whereas, she says, nobody seems to like the tau.
Like any good scientist, Julie will soon explore new territories. Her next toy will be the "quantum duck", due to be made available this summer. "The quantum duck is my secret project," reveals Julie. "It is going to be Russian dolls – you keep opening the doll and you have the duck, the molecule and it's going down to quarks and keeps going further and further down." Why a duck? "I think at the time, when the idea came to me, my calendar had some ducks on it. So, I decided to do a duck!"
Nothing is out of reach for Julie's artistic imagination. In her zoo, particles can decay and reveal new objects created in the interaction. "I did the decaying top quark for Fermilab. It is a plushie that reverses inside out with a zipper to a big bottom quark and has a mini anti-muon and a mini muon–neutrino inside. I would like to do the neutron decay in the same way."
When particles have exhausted their inspiring power, Julie will turn her attention to cosmology. "In future I am going to do more objects from space, such as black holes and pulsars," she confirms. A first example represents the cosmic microwave background radiation. In the meantime, she also wishes to see her particles animated.
• To find your favourite particle, visit the zoo at www.particlezoo.net/.