Mixtures, Solutions & Separation
📋 What it is
A mixture combines substances without changing them; we can separate them by their properties.
🗣️ Coach says
Mix sand and salt and nothing chemically changes — that’s a mixture. Dissolve salt in water and you get a solution (a special evenly-mixed mixture). Because the substances keep their properties, you can separate them again: filter the sand, evaporate the water to get the salt back.
🧠 Memory hook
Mixture = combined but unchanged → so you can separate it back out.
😂 Giggle
Why did the noble gas cry?
Because all its friends argon!
😲 Whoa!
Seawater holds so much dissolved salt that if you spread ALL the ocean’s salt over land, it would form a layer over 150 metres thick.
✅ Quick check: You dissolve sugar in water. Can you get the sugar back?
Say your answer out loud first — then reveal.
Yes — evaporate the water and the sugar is left behind; dissolving is a mixture, not a permanent change.
In a solution the substances keep their identity, so separation is possible.
🧪 Try it! (2 minutes)
Stir salt into warm water until it vanishes, then leave it on a sunny sill. The salt reappears as the water evaporates.