By the end of the lesson the learner can name the three sub-atomic particles and state the charge and relative mass of each.
By the end of the lesson the learner can describe how protons, neutrons and electrons are arranged inside an atom.
By the end of the lesson the learner can relate the structure of the atom to everyday materials in Kenya.
Transcript
[0:00] Everything around you, from a matatu's metal body to the water in a borehole, is built from tiny particles called atoms.
[0:35] An atom has a central core called the nucleus. Inside the nucleus are protons, which carry a positive charge, and neutrons, which carry no charge at all.
[1:20] Moving around the nucleus are electrons. Each electron carries a negative charge and has almost no mass compared with a proton or a neutron.
[2:05] Because protons are positive and electrons are negative, a neutral atom must have equal numbers of each, so the charges balance out.
[2:50] The proton and the neutron each have a relative mass of about one unit, while an electron is roughly one over eighteen-hundred of that, so nearly all the mass sits in the nucleus.
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