High School Teachers at CERN
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Consistency of language.

A paper originally written by Rita van Peteghem.

In different resources one finds different terms talking about the same topics. This particular one was a frequent topic of conversation in HST 2000.

In every physics textbook for secondary school force is defined as "every cause of acceleration or distortion". (That makes it very difficult to talk students about the weak force for example.) In particle physics the word force carries another meaning then in the textbooks for general physics. This further produces misconceptions. 

1.1. Our proposal is that in talking to the general public and in talking to secondary school students we use the word "interaction" instead of "force" when talking about force at its most fundamental level. When one talks about the four fundamental interactions, students intuitively accept the Feynman diagrams. In these diagrams the interactions between matter particles are visualized from the passage of other "messenger particles" between them. 

When one wants to talk about the gravitational force students are already familiar with, one can say that the gravitational interaction expresses itself in the attractive gravitational force between masses. The electromagnetic interaction expresses itself as the attractive or repulsive force between charges, or in the attractive or repulsive force between magnets, or in the Lorentz force a moving charge can feel in a magnetic field. The weak interaction can make particles change. The strong interaction holds quarks together in composite matter particles. 

In the Collins dictionary (1995) the definition of interaction is: 

'When one thing interacts with another or two things interact, the two things affect each other's behavior or condition'. That is completely compatible with what the four fundamental interactions in nature do. 

 
1.2. We suggest using the term 'strong interaction' only for the interaction between quarks. Then we can talk about the force between the particles of a nucleus as a consequence of that strong interaction between quarks. Students can intuitively understand that when one knows the properties of the interaction between quarks, the properties of the force between combinations of quarks can be derived. 

1.3. We suggest using systematically the word "fundamental" particles when we speak about the quarks and the leptons. One can say that: "Fundamental particles build up matter and messenger particles bind matter". 

 

1.4. We suggest speaking about three "generations" of the fundamental particles or the basic building blocks of nature. 

(We can talk about the leptons as the family of the electrons.)