Separation Station
Pull a mixture back into its parts.
What this lesson covers
Why it matters
Salt hides in sea water, iron filings lurk in sand, mud clouds your drinking water. Every mixture has a trick to pull its parts back out.
Predict first
Why can you separate a mixture by physical means, but not a compound?
A mixture's parts keep their own properties, so physical methods — filtering, evaporating, a magnet — pull them apart. A compound needs a chemical reaction.
- A mixture's parts aren't chemically bonded, so physical tricks work — correct
- Mixtures are lighter than compounds
- You can't really separate either
What you do
Pick the technique that separates each mixture into its parts.
Check yourself
How do you get pure salt back from salt water?
Salt is dissolved, so filtering won't catch it — evaporate the water and the salt is left behind.
Sand does not dissolve in water. To remove it you…
Filtration traps undissolved sand while the water passes through.
Which mixture can a magnet separate?
Only magnetic materials like iron respond to a magnet.
- Evaporate the water away — correct
- Filter it
- Use a magnet
- Filter the mixture — correct
- Evaporate the water
- Use a magnet
- Iron filings from sand — correct
- Salt from water
- Sugar from tea