Matter can be understood by applying two scientific models: particles, and waves
Particles are objects that are hard, have mass, and move according to Newtonian mechanics. Particles are a macroscopsic model which can be applied to the microscopic world. Kinetic model of a gas: gas molecules are small, hard particles bouncing off of one another and the walls of their container. Macroscopic phenomena of pressure and volume are explained in terms of masses and speeds of the microscopic particles. Particles show reflection and refraction.
Waves are shaped like a sine graph, but in practice waves are never shaped exactly like these. Complicated waves can consist of much simpler waves.
Waves are a way in which energy is transferred from one place to another. In a wave, something is changing in a regular way while energy is travelling/transferred along. In water waves particles of water move up and down while energy is transferred horizontally. Waves show reflection, refraction, diffraction, and interference but the last two are the defining characteristics of waves. If diffraction and interference are observed, waves are involved. Waves do not have mass or charge.
All electromagnetic radiation consists of photons.
A photon is a packet of energy, or a quantum of electromagnetic energy. Gamma-photons are the most energetic out of all the types of photons. The energy of a photon is directly proportional to the frequency of the electromagnetic radiation of which it is a part of, so high frequency radiation means high energy photons.