From ancient times we have observed the nature and tried to find explanations and fundamental causes for the phenomena we encounter. The Antique people thought that everything can be explained as a combination of four basic elements: earth, water, air and fire. Although not very precise in explanations, their intuition was good, today we use the classification: solid, liquid, gas and plasma for the explanation of the matter states. More than that, their idea of an ultimate form of matter that you can reach by continuous division, was confirmed and it is still used today by the researchers who study the particle physics.

The current picture that we have today about the elementary structure of nature, refined after more than a century of modern researches, is the following: the matter is made up of two classes of particles, leptons and hadrons which interact with each other by means of four fundamental forces: strong force, electromagnetic force, weak force and gravitational force (except the leptons which don’t “feel” the strong force, but only the other three). This set of basic elements and their compounds, which together form the so called Standard Model of elementary particles, allows one to explain the wide range of phenomena we experience from the sub-microscopic scale to the astronomical one and the scale of the evolution of the Universe.

The present set of learning activities, separately adapted to the level of lower and higher secondary school pupils, focuses on notions about the Standard Model and the way it is investigated today in research laboratories. By means of lectures, films and applications we present concepts about particles classifications, conservation laws, particles trajectories and particles decays. The exercises accompanying the lectures are inspired and use resources developed by the educational program International Masterclasses http://physicsmasterclasses.org/, which use data from real experiments and visualization tools made available by researchers in the field.

Elementary particles and fundamental forces