Quick check: choosing a separation technique

Classroom resources

Load these into Waypoints Prepare: choose Load URL and paste the copied address, or download the file and import it. In Prepare, the worksheet's Teacher edition shows the answers; the student copy hides them.

• Slides Download Copy address for Prepare Present from the browser, or export to PowerPoint or PDF.
• Worksheet Download Copy address for Prepare Print the student copy; the Teacher edition has the answers.

Students will be able to

• I can match a mixture to a separation technique.
• I can put the steps of a separation in a sensible order.
• I can say why one technique would not work on a given mixture.

Timing

About 10 min

Before class

A Quick check: a few questions on what students should know for AC9S7U06 node 5, which you teach in class. It has no board, no clip and no new teaching, and it is optional, so it never holds up course completion. Set the width with ?width=minimum, typical (default) or wider.

Use it as a self-test after your teaching, a starter, or revision. The strongest version of this node is on the bench with a mystery mixture. Use these questions to settle the reasoning first, or to review afterwards.

Running the lesson

1. Do the match first, then ask a student to justify two of them with a property.
2. The order question links to the sand, salt and water practical.

The hard part (on purpose)

Justifying with a property rather than naming the technique. When a student says "use a filter", ask what the filter paper tests.

When students get stuck

Answers to the checks

1. Match the technique: Which technique separates this mixture?
   Iron filings from sand → Magnet; Sand from water → Filtering; Salt from salty water → Evaporation; Pure water from salty water, collecting the water → Distillation; The colours in a felt-tip ink → Chromatography
2. In what order?: A mixture of sand, salt and water is to be separated into all three. Which plan works?
   Filter out the sand, then evaporate the water to leave the salt
   Filtering removes the sand because it is too big to pass through. The salt is dissolved, so it passes through with the water; evaporating the water leaves the salt.
3. A technique that fails: Why will filtering not separate salt from salty water?
   Dissolved salt particles are tiny and pass through the holes in the paper with the water
   Filtering separates by particle size. Dissolved particles are far smaller than the holes, so they go through.

Stretch and support

Stretch: Design a way to separate salt, sand, iron filings and wood shavings. What is the best order, and why?

Support: Give a table with columns: part, property, technique. Students complete it for each part.

Coach prompt (optional)

For a student who has done the lesson and is still stuck. They paste it into an AI tool your school allows; it asks questions about this lesson's one idea and doesn't give answers. Students see it on the course recap page only through a link ending in ?coach=1: recap with coach prompts.

You are a patient science coach for a Year 7 student in Australia. Help me understand ONE idea only, from the lesson "Quick check: choosing a separation technique".

The idea: Selecting and justifying separation techniques: I can select and justify an appropriate separation technique for an unfamiliar mixture using property differences.

What understanding looks like:
- Selects an appropriate technique for an unfamiliar mixture
- Justifies the choice using property differences
- Identifies at least one technique that would not work and explains why

Mistakes students often make here:
- A student says the filter catches sand because it is heavier.
- A student would evaporate first when sand is present.

How to coach me (rules from the Waypoints Kit coach):
- Ask me one short question at a time (2 to 4 sentences) and wait for my answer. Never give me the answer before you have heard my thinking, and don't hide the answer inside your question.
- Start in Discover: ask me to explain the idea in my own words, or to predict what happens in a simple example. I can switch any time: "teach it back" (you play a beginner and I explain), "spot the flaw" (you show me an answer with one common mistake and I find it), or "check" (I explain, and you tell me what is solid and what to revisit).
- If I am stuck or say "just tell me", ask what I think first, then give a small hint or a simpler example. Explain only after I have had a real go.
- If I seem to be missing the idea that comes before this one (Distillation and chromatography), check it quickly, then come back.
- Stay in this idea: don't teach later ideas or add extra content. If I ask about something else, say it is for another lesson and bring me back.
- After you help, ask me one reflective question, such as how I know my answer is right or what I would check.
- Praise my effort and method, not my ability.
- You can be wrong: if I rely on something you said, remind me to check it against my notes or the lesson. If you don't know, say so.
- Use simple words.
- Stop when I can explain the idea in my own words and get one new example right. Then tell me to go back to the lesson "Quick check: choosing a separation technique".

Exit ticket

Why does a magnet separate iron filings from sand?

Iron is magnetic and sand is not, so the magnet uses that difference in property.

What each step is for

• Choose and justify: Node 5: choose a technique for a mixture using property differences, put steps in order, and explain one that would not work.

Where it leads

Back in class: a practical separating an unfamiliar mixture, with a written justification.