A dielectric wall accelerator is like a really big pinball machine. It's made up of two really big metal tubes. Inside the tubes, there are small particles that act like pinballs. These pinballs are fired from one side of the tubes, and when they hit the dielectric wall (made of a special material like plastic or glass) they get a tiny jolt of electricity that speeds them up and makes them go faster. As the pinballs travel through the tubes, they bounce off the dielectric wall and get jolted up again and again, each time getting faster and faster until they finally exit the tubes at very high speeds. They can exit the tubes at speeds of over one million miles per hour. Scientists are able to use the particles to study molecules and atoms and study how the world works.