These particles, called photons, are the most basic units of light.

According to quantum theory, each is made of three particles called quarks.

This more powerful force is mediated by particles called gluons.

Electricity, first thought to be a fluid, was now understood to consist of particles called electrons.

But since Einstein, we know that light consists of particles called photons.

The forces are also made from particles, called quanta.

He discovered the properties of these particles, now called cathode rays.

Elements are made of extremely small particles called atoms.

Also shooting around within the nucleus are the six less active particles called neutrons.

You know that light is made up of particles called photons.