Science lesson plan · 6th grade (Year 7 in England) · 45 minutes
Solutes, solvents and how much will dissolve
Materials and their properties
CCSS NGSS.MS-PS1-2England: KS3 Chemistry: Pure and impure substances
Objective and success criteria
Students will: Solutes, solvents and how much will dissolve.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Dissolving and solutions
Leads to: Choose the right technique to separate a mixture; Concentration in grams per dm³
Materials: A tray of everyday objects, Sorting hoops, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Dissolving and solutions). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Is rice soluble or insoluble in water? (soluble (dissolves in water) / insoluble (does not dissolve)) → insoluble (does not dissolve)Prompt: Imagine stirring it into a glass of water. Would it disappear from view?
- 5 g of sugar is dissolved in 300 g of water. What is the mass of the solution, in g? → 305 gPrompt: When something dissolves, does it disappear or is it still there?
- Which change makes sugar dissolve faster? (leaving it still / using warmer water and stirring / using colder water / using bigger sugar lumps) → using warmer water and stirringPrompt: Particles move faster when they are warmer.
Hook · 5 min
- Pass round objects made of different materials and ask why each one was chosen.
- Share the objective: Solutes, solvents and how much will dissolve. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Which word describes this: the clear mixture made when sugar dissolves in water?
- Step 1: A solution is the mixture of solute and solvent.
- Step 2: So the answer is: solution
- Answer: solution
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Which word describes this: sand that sinks to the bottom of water? (solute / solvent / insoluble / solution) → insolublePrompt: Solute + solvent → solution.
- At 20 °C, 200 g of sugar dissolves in 100 g of water to make a saturated solution. What mass dissolves in 300 g of water at 20 °C, in g? → 600 gPrompt: How many lots of 100 g of water are there?
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- At 20 °C, 32 g of potassium nitrate dissolves in 100 g of water to make a saturated solution. What mass dissolves in 150 g of water at 20 °C, in g? → 48 gPrompt: How many lots of 100 g of water are there?
- A student adds salt to water until some stays on the bottom however much they stir. What have they made? (an insoluble solvent / a saturated solution / a pure substance / a gas) → a saturated solutionPrompt: No more salt can dissolve.
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: Dissolving and solutions.
- Use concrete materials: a tray of everyday objects.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Choose the right technique to separate a mixture; Concentration in grams per dm³.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-6.
Free lesson plan from eurekami.com/lesson-plan-builder