by placing a crystal at different concentrations of Visking tubing bag. the bottom of a large solution. Using a coloured B1.17 Calculate percentage gain beaker of water. Ask sugar syrup, such as Explain to students that and loss of mass in osmosis students to work in pairs blackcurrant squash, makes it glucose and water to discuss why the colour easier for students to see that molecules are small Investigate osmosis in B1.16 disperses through the the solutions are of different enough to cross the potatoes water. Ask where in the concentrations. membrane, but that water the manganate is starch molecules are Students should find that the most concentrated at the not. Ask students to potato strip in pure water start, and how work in pairs and use gains mass, while the rest lose concentration of that information to help mass in relation to how much manganate at any them predict whether water was in the solution (i.e. particular point in the diffusion and osmosis the potato in the solution with water changes over time. will occur over that least water [100% solution] Use this to lead to a time, and in which loses most mass). definition of diffusion, as direction. the overall movement of Equipment: Per group: 4 particles from where Digital: Osmosis potato strips of identical size, there are more of them animation accurate balance, 4 boiling (higher concentration) to tubes and rack (or beakers), where there are fewer (a waterproof pen, 4 labelled lower concentration). solutions containing different amounts of water, forceps, Equipment: Large paper towels. beaker of water, potassium manganate(VII) crystal, tongs – alternatively video of diffusion of potassium manganate(VII) in water.
B1.17 B1.16 Calculate percentage gain and loss of mass in osmosis Investigate osmosis in potatoes by placing a crystal at the bottom of a large beaker of water. Ask students to work in pairs to discuss why the colour disperses through the water. Ask where in the water the manganate is most concentrated at the start, and how concentration of manganate at any particular point in the water changes over time. Use this to lead to a definition of diffusion, as the overall movement of particles from where there are more of them (higher concentration) to where there are fewer (a lower concentration). Equipment: Large beaker of water, potassium manganate(VII) crystal, tongs – alternatively video of diffusion of potassium manganate(VII) in water. different concentrations of solution. Using a coloured sugar syrup, such as blackcurrant squash, makes it easier for students to see that the solutions are of different concentrations. Students should find that the potato strip in pure water gains mass, while the rest lose mass in relation to how much water was in the solution (i.e. the potato in the solution with least water [100% solution] loses most mass). Equipment: Per group: 4 potato strips of identical size, accurate balance, 4 boiling tubes and rack (or beakers), waterproof pen, 4 labelled solutions containing different amounts of water, forceps, paper towels. Visking tubing bag. Explain to students that glucose and water molecules are small enough to cross the membrane, but that starch molecules are not. Ask students to work in pairs and use that information to help them predict whether diffusion and osmosis will occur over that time, and in which direction. Digital: Osmosis animation
GCSE9-1ScienceTerm1detailedplanning-UPDATE1.docx