Science at key stage 3    (Year 7)

• classify materials as solid, liquid or gas
• offer explanations (which may be incorrect) in which they try to link their existing knowledge to observations, eg
• the syringe which contains a solid won't squash because it's got no air in it
• the metal rod expands because the particles get bigger
• evaluate their own explanations and those given by others

• evaluate the ideas of others and collectively create a solution to the game/puzzle which is consistent with the evidence
• explain how their solution is consistent with the evidence and, if necessary, why they had to change their ideas

• classify materials and justify their classification in terms of properties of solids, liquids and gases
• explain why some materials are difficult to classify
• generate descriptions of solids, liquids and gases consistent with the evidence and their scientific knowledge, eg a solid is made of tiny grains all glued together
• design a key to classify materials as solid, liquid or gas

• describe in writing and drawing the arrangement, proximity and motion of particles in solids, liquids and gases
• describe how particle theory can explain some phenomena, eg diffusion of a gas, mixing of liquids, expansion of a metal bar

• explain observations in terms of particles
• evaluate their own explanations and those of others

• explain their observations using the particle theory
• identify where there are contradictions in their ideas, when these are pointed out
• describe gas particles as moving all the time and pushing against surfaces
• explain that the can collapses because there are fewer air particles on the inside pushing out than on the outside pushing in

• draw and describe particles in solids, liquids and gases in terms of the movement and proximity of their particles
• describe observations they have made and explain them, eg a metal block is heavier than a wooden block because the particles are heavier or because the particles are closer together