Matter & Materials and States of Matter
What do we call anything that has mass and takes up space?
Matter — anything that has mass and takes up space.
Which state of matter takes the shape of its container but keeps the same volume?
Liquid.
What do we call the change from solid to liquid?
Melting.
Is melting chocolate and then letting it harden again an example of a reversible change or an irreversible change? Explain briefly.
Reversible — chocolate melts (physical change) and can harden again when cooled.
What is the difference between "matter" and "material"? Give a short example of each.
Matter is the stuff that makes up everything; a material is a kind of matter used for something (example: matter = water; material = metal).
Which state of matter keeps a shape and volume?
Solid.
What do we call the change from liquid to solid?
Freezing (solidification).
Is burning a piece of paper reversible or irreversible? Explain why in one sentence.
Irreversible — burning paper makes ash and new substances; it cannot be turned back into the original paper.
Name the three most common states of matter students learn in Y6.
Solid, liquid, gas.
Which state of matter spreads out to fill all available space and has no defined shape or volume?
Gas.
What is the melting point? Explain in one sentence.
The melting point is the temperature at which a solid becomes a liquid.
Give two classroom examples of reversible physical changes and two examples of irreversible changes.
Reversible examples: melting ice to water, dissolving sugar in water (if recovered by evaporation). Irreversible examples: burning paper, baking a cake (new substances form).
Describe how particles are arranged in a solid compared to a gas.
Solids: particles packed closely and vibrate in place. Gases: particles far apart and move freely.
Explain how particle motion differs between a liquid and a gas in one or two sentences.
Liquid particles move past each other but stay close; gas particles move fast and spread far apart.
Use the particle model to describe what happens to particles when ice melts into water (2–3 short sentences).
Liquid particles move past each other but stay close; gas particles move fast and spread far apart.
A student mixes sand and water. Can they get the sand back by physical means? Is this reversible or irreversible? Explain how they would separate them.
Reversible — you can separate sand from water by pouring or filtering and letting water evaporate (or using a filter).
Give an example of a material and tell which state of matter it is in under normal room temperature and why.
Example: Water is usually a liquid at room temperature because its particles move enough to slide past each other but stay close.
What does "thermal conductivity" mean? Give a simple classroom example of a material with high thermal conductivity and one with low thermal conductivity.
Thermal conductivity is how well a material lets heat move through it. Example high: metal spoon (gets hot quickly). Low: wooden spoon or foam cup (stays cooler).
A puddle of water disappears on a warm day but did not soak into the ground—what change of state likely happened? Explain the particle behavior that makes this happen.
Evaporation (or vaporisation). Particles at the surface gain energy, move faster, and escape into the air as gas.
Explain, using the particle model and the idea of new substances, why some changes are irreversible while others are reversible. Give one real-life example of each.
Reversible changes are physical: particles rearrange but the substance stays the same (e.g., melting ice). Irreversible changes produce new substances or break bonds so the original can't be easily recovered (e.g., rusting iron or burning wood).