1.1 Characteristic of the Big Idea

According to the concept of Harlen´s Big Idea in Science, this particular Scientific Idea covers following understanding of the particular natural phenomena: “Atoms are the building blocks of all matter, living and non-living. The behaviour and arrangement of the atoms explain the properties of different materials. In chemical reactions, atoms are rearranged to form new substances. Each atom has a nucleus containing neutrons and protons, surrounded by electrons. The opposite electric charges of protons and electrons attract each other, keeping atoms together and accounting for the formation of some compounds.” (Harlen, 2015)

1.2 Suggested development of the Idea at primary education level (7–11 year – old pupils)

Big ideas are at primary age in an intense development. To support the further develo-pment of the Idea, pupils at primary age should be exposed to the following level of the Idea: “When some substances are combined, they form a new substance (or substances) with properties that are different from the original ones. Other substances simply mix without changing permanently and can often be separated again. At room temperature, some substances are in the solid state, some in the liquid state and some in the gas state. The state of many substances can be changed by heating or cooling. The amount of matter does not change when a solid melts or a liquid evaporates.”(Harlen, 2015)