Visitor's Handout: The Story of the Lederman Science Center's Exhibits

The Ideas - What We Study

There is an amazing beauty and symmetry in nature. A snowflake, a daisy, a honeycomb. The shapes of these and all other natural objects depend on an underlying structure of matter. For centuries scientists have wondered what this structure is like. Their studies have led to a search for particles that are the basic building blocks of matter and forces that control their behavior. The particles are quarks and leptons; the forces are gravity, electromagnetism, weak and strong. Scientists who work at Fermilab are leaders in the international search to learn how the universe works.

Methods - How We Work

Scientists work by posing important, new questions, developing theories, and inventing tools and techniques to answer their questions and test their theories. Scientists need to have a lot of particles together in one place to study, so they make their own. Scientists at Fermilab create particles by colliding protons into particle targets. Sometimes the protons collide with fixed particle targets (hydrogen ions, iron, tungsten, etc.) In other experiments, protons collide head-on with a second beam of protons. When these collisions take place (scientists call them events), new particles are created. Scientists record and study how the newly created particles move away from the collision point (scatter). By observing this behavior of the particles, scientists can learn about them and the forces that control their interactions and sometimes discover particles not seen before.

Tools - What We Use to Do Our Work

The instruments that particle physicists use for their studies include accelerators, detectors and powerful computers. Accelerators increase the energy of the protons. The smaller the particle to be studied, the higher the energy (mass) of the protons, and the bigger the accelerator must be. The particles scientists want to study are so small that they cannot be seen by the human eye or the most powerful microscope. They build huge detectors to track the particles as they move. Scientists need computers to collect, store and analyze the information because the experiments create a lot of data over a very short period of time, because many of the newly created particles live for fleeting moments, and because the computer allows scientists to reconstruct the data into an event.

Connections - The Biggest and Smallest Things in the Universe

When scientists study these particles and the forces that bind them together, they also learn about the history of the universe and how it began with the Big Bang. When the universe was very young, there weren't even atoms; it was too hot for them to form. The only form of matter was a primordial soup consisting of the most basic particles such as quarks and electrons. At Fermilab, scientists make the ingredients of primordial soup by smashing together protons at very high energies in the Tevatron. The earlier we look in time, the fewer and more basic the particles become, and the fewer the forces are needed to control their behavior. The laws of physics are valid in the whole universe and throughout the whole of time.