Chromatography Basics

Overview

In this lesson (Lesson 8 of 18), students are introduced to chromatography as a separation technique. They build from prior ideas about mixtures and properties of matter to explain how the properties of substances enable separation in chromatography.

Learning intentions

• WALT understand what chromatography is and how it separates mixtures.
• WALT describe, using evidence, how different substances move through paper at different rates.
• WALT recognise common real-world applications of chromatography.

Success criteria

Students can:

• I can explain that chromatography separates components based on how they travel on a medium.
• I can describe what happens to pigments/colours as the solvent moves up the paper.
• I can identify at least two real-world uses of chromatography.

Curriculum links

• SC4-SOL-01 — Students explain how the properties of substances enable separation in a range of techniques.
• SCLS-SOL-01 — Students describe the properties of familiar substances and materials (link to properties like solubility and different behaviours).
• SC4-WS-04 — Students follow a planned procedure to undertake safe and valid investigations (students follow steps during the demo/group activity).
• Key science practices: using evidence from observations to support explanations (observing patterns, reasoning with cause and effect).

Lesson structure ({total minutes})

1. 0–5 min · Hook with interactive demo (front-loaded). Teacher displays prepared chromatography strips and solvent cup (or projects a teacher demo), then asks: “What do you think makes the colours separate?” Students make a quick prediction and justification (think-pair-share).

2. 5–12 min · Modelled explanation (concept building). Teacher explains chromatography using a simple sequence: sample spot → paper absorbs solvent → solvent carries components → components separate based on how far they travel. Students record the process on a class anchor diagram (sentence starters provided for autistic students).

3. 12–20 min · Guided small-group chromatography (hands-on, safe procedure). Teacher groups students (3–4 per group) and provides a worksheet sheet with multiple-choice steps and a checklist for procedure. Teacher circulates to ensure correct placement of the pencil line and that the spot stays above the solvent. Students complete their chromatography strip and observe as it develops, recording what they see using multiple-choice “What happened?” questions.

4. 20–24 min · YouTube clip and quick check. Teacher plays “Chromatography for Kids” (no pauses longer than needed). Students answer two rapid-response questions on a mini handout (multiple-choice): “What separates?” and “Where does the separation happen?”

5. 24–30 min · Independent worksheet wrap-up (uses of chromatography). Students complete an independent multiple-choice worksheet: identifying applications (e.g., forensics, testing food/drinks, identifying inks/pigments). Teacher collects for feedback and gives a 30-second closure: students share one application and link it back to “properties enabling separation.”

Resources

• Pre-cut chromatography paper strips (lightweight paper) and pencils (no ink pens on the paper)
• Marker dots or washable food-colour mixes (teacher-prepared “samples” for consistency)
• Small cups/containers with solvent (teacher-selected appropriate solvent; follow your school safety procedures)
• Paper towels, trays, gloves/aprons as required by your school plan
• Group worksheet (multiple-choice procedure + observation questions)
• Independent worksheet: “Uses of chromatography” (multiple-choice)
• Timer and class anchor chart template (chromatography steps)
• “Chromatography for Kids” YouTube clip (prepared for play; teacher controls playback)
• Projector/whiteboard for demo images/diagram

Assessment

• Teacher observations during group work: correct setup (spot above solvent line, patience during development) and safe handling.
• Formative checks:
• Quick think-pair-share prediction at the start (hook).
• Multiple-choice “What happened?” and “What separates?” during the clip.
• Final independent worksheet on applications (link to SC4-SOL-01 explanation of why separation works).

Differentiation

• Autistic-friendly supports:
• Provide clear visual steps on the anchor chart and on worksheets (numbered sequence with picture cues).
• Use sentence starters for explanations (“Chromatography separates… because…”).
• Reduce language load in questions; keep options short and distinct for multiple-choice items.
• Support:
• Provide a “word bank” near tables: sample, solvent, paper, spots, separate, travel, distance.
• Offer an additional teacher group prompt: “Which colour went farther? What does that tell us?”
• Extension (for early finishers):
• Add one extra multiple-choice challenge: choose the best factor explaining separation (e.g., different solubility or attraction to paper) and justify with one sentence.
• Safety and access:
• Assign roles within groups (materials handler, observer, recorder) to reduce sensory overload and improve participation.

Extension (optional)

SKIP