‘Particles’ is a word from everyday experience, generally referring to small bits of stuff, In science, we borrow the term ‘particle’ to get across the theoretical model that all material is composed of myriad tiny sub-microscopic quanta of matter. These ‘particles’ of ‘particle theory’ are not like the hard discrete grains of sugar or sand with their definite edges and surfaces, but rather fuzzy balls of fields with no clear boundaries. The particle theory is valuable in science because the familiar properties of materials can be understood in terms of the behavior, arrangements and interactions of these very different ‘particles’ (or should we call them quanticles).
Sandra was a participant in the understanding science project. Sandra (year 7, 11-12 years old) has learnt that everything contains particles, but to her particles are the small bits of materials like salt. She found it difficult to understand how these particles of which everything was made relate to the particles she is already familiar with. This became clear when she talked about dissolving. She knew that if salt was dissolved, it could be recovered from solution by boiling off the water:
“you can like, … boil the water so it turns into gas, and then you have salt, … left there.”
However, it would not appear the same, as:
“You’d have the same, but there would just be more particles, but they’d be smaller.”
According to Sandra “Everything has particles in it” and most things would have “like thousands and thousands of particles inside it.” The grains that Sandra could see were “sort of (particles) but you’ve got more particles inside that.” However, when asked if there were two types of particles, Sandra reported that “I don’t know.”
So although Sandra had learnt about the particulate model of matter, and accepted the premise that “everything has particles in it” she was not sure if this was just a matter of scale, with these particles being very much smaller versions of the grains that were visible in a material like salt.
We should not be surprised that pupils gets confused when we chose to use a familiar word as a label for a new concept. Quanticles are very unlike familiar particles. Even in terms of scale, the very characteristic that leads to the analogy with particles. This is an example of everyday language leading to an associative learning impediment, triggering existing knowledge - in the case the usual meaning of 'particle' - in unhelpful contexts.
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Dr Keith S Taber kst24@cam.ac.uk
University of Cambridge Faculty of Education