Advanced Material Properties

Activities to try

1. 1

   Materials test lab: run the tests, fill the table

   Why it works: Each property can be measured by an isolated fair test, and materials can be grouped and compared from the recorded evidence rather than from assumptions about what a material 'should' do.

   1. Set up a specimen rack with tiles of different materials (e.g. copper, iron, aluminium, glass, wood, plastic, rubber, chalk).
   2. At a circuit station, use a low-voltage battery circuit. Clip each tile into a gap in the circuit and observe whether the bulb lights (an optional conductivity reading makes this more concrete). Record conductor/insulator plus any measured value. Note that a simple bulb circuit usually cannot show differences between metals, because all the metal tiles light the bulb about equally.
   3. At a heat station, stand one end of each tile (or same-sized strips) in the same amount of hot (not boiling) water, never in a flame, because wood, plastic and rubber can burn, melt or give off fumes. Time or watch how fast heat travels to the other end, for example with a heat-sensitive strip or a small blob of butter or wax at the far end. An optional colour-gradient-over-time display or timer can make heat travel visible. Record how fast heat moves.
   4. At a scratch-hardness station, try scratching each material against the others to rank relative hardness; record the scratch order.
   5. At a dissolve station, use small granular or powdered samples rather than the tiles. Include some soluble solids (e.g. salt, sugar) alongside insoluble ones (e.g. sand, powdered chalk). Stir the same measured amount of each into the same fixed amount of water at the same temperature, and record whether it dissolves (soluble/insoluble).
2. 2

   Pick the material for the job

   Why it works: The right material depends on which measured property the job needs; evidence from your own table, not the object's name or tradition, justifies the choice.

   1. Take a specific brief, e.g. 'choose the best handle for a hot pan' or 'choose the best core for an electromagnet'.
   2. Sort or scan the completed properties table to find which materials score best on the property the job actually needs.
   3. Notice when a material does well in one column but fails another. For example, copper conducts electricity well, yet a metal handle fails the heat-safety requirement because it conducts heat too well.
   4. State a choice and justify it by citing the specific measured property from the table (e.g. 'plastic for the handle because it is an insulator and heat travelled slowly through it in our test', 'copper for the wire because it conducted electricity in our test').
   5. Compare two metals for the same job (e.g. copper vs iron for a wire) and explain what the recorded results show. If the simple circuit showed no difference between them, say so, and note that other properties (e.g. bendiness, rusting) or measured conductivity readings would be needed to decide.
3. 3

   Predict-then-test the magnet (not all metals are magnetic)

   Why it works: Being attracted to a magnet is a property of only some metals (mainly iron, most steels, nickel and cobalt), not a defining feature of all metals; a quick fair test settles it.

   1. Lay out an aluminium drinks can, a piece of solid copper (e.g. copper wire or pipe), a steel paperclip and a brass key. Avoid 'copper' coins: many, such as UK 1p and 2p coins made since 1992, are copper-plated steel and are attracted to magnets.
   2. Before testing, predict which the magnet will pick up and write down WHY.
   3. Test each one with the magnet and record what actually happens. If the objects really are aluminium, solid copper and solid brass, only the steel paperclip will be attracted.
   4. Compare the prediction with the result and, if 'all metals are magnetic' was assumed, correct it: name the common magnetic metals (iron, most steels, nickel, cobalt) and the non-magnetic ones just tested (aluminium, copper, brass).
   5. Answer a follow-up: name a metal a magnet will NOT pick up.