Lesson No: I Unit Title: Solutions
 Lesson 2Lesson 3Lesson 4Lesson 5

Unit No: 7H

Lesson Title: The solution is clear (part 1)

NC Ref:
Sc3 1g 2b

Objectives:
MK - Mixture, dissolving, solution, solute, solvent, soluble, insoluble, clear, colourless, cloudy, transparent.
SK -
CK­

Lesson outline: All MK

  • Target sheet and Quiz sheet or Interactive quiz sheet.

  • Show a selection of gas jars with stuff in. Get the class to write on A4 laminated cards whether they thing it is a mixture or not.

  • Hold 2 beakers of water (one having salt dissolved in; don’t tell them one is salt water). Ask students to decide whether they are mixtures or not.  Get a student to dip his finger in and taste each one. The salt water is a mixture as it contains salt that cannot be seen. CAP (Thinking Skills)

  • Make a cup of tea or real coffee. What is the purpose of the tea bag or coffee filter (could be done with a cafetiere).

  • Lead the discussion that part of the tea/coffee is soluble and part of it is insoluble and the bag/cafetiere is used to separate the insoluble part from the soluble part.

  • Practical — Testing solubility. Mix the end of a spatula of solid in a test tube of water and stir. Leave for 2 mins then look again. Students are to describe the resulting mixture and decide whether the resulting mixture is soluble or insoluble. With some students introduce the terms ‘partially soluble’, ‘mostly soluble’. (There is no fill in sheet for this)

  • Keep the solutions for next lesson

  • SK — Try dissolving these solutes additional solvents.

Plenary - Go through descriptions of the solutions:
            Clear or transparent (even with a colour) = soluble
            Cloudy = partially or mostly soluble
            Cloudy that sinks = insoluble
            Solute = solid that dissolves
            Solvent = liquid that does the dissolving / there are other solvents
            Solution = when a solid has dissolved in a liquid / solute in solvent

Time

Homework: wls 7Ha/3

Resources:  W/s — 7H Target sheet and quiz sheet. W/s — 7Ha/3 — dissolving key words. Gas jar 1 — Half filled with sand — sugar mix. Gas Jar 2 — half filled with wood shavings. Gas Jar 3 — Half filled with iron wool. Gas jar 4 — Half filled with wood shavings iron wool mix. Salt solution. Glass rods. Spatulas. Sugar, salt, flour, instant coffee, soap shavings, pepper, baking soda, aspirin. Kettle. Caffetiere, tea bags, filter coffee, milk, squash detergent, vegetable oil. Exploring science 7

 

Risk Assessment: safety glasses.