Watch UO physicist–and IFS Director–Graham Kribs walk you through one of the seminal experiments that helped open the quantum age.

9 April 2025 || University Communications

Quantum mechanics is a branch of physics that attempts to explain the behavior of matter and energy at their smallest level, down to the size of subatomic particles like electrons, photons and quarks. And at that size, reality is very different from our everyday world.

The quantum world is distinct from the classical world familiar to us because particles in the quantum world exhibit both particle-like and wave-like behavior. This is most easily seen by comparing the results of a double-slit experiment with sand, waves and then quantum particles like electrons.

Electrons exhibit wave-like behavior when no one is looking at which slit they go through. But when a detector is used to obverse which opening the electron goes through, the resulting pattern immediately switches to particle-like behavior. The act of looking changes the result, collapsing the quantum wave-function.

Why is that important? That wave-particle duality is at the heart of quantum mechanics, and quantum mechanics is at the heart of nearly all of the modern world’s technology, from cellphones to lasers to medical imaging and quantum computers.

In this video, UO physicist Graham Kribs walks us through the double-slit experiment and gives us a peek into the world of quantum mechanics.