Lesson 2 Two variables
Note: advance preparation needed for Activity 3, which needs either a week to dry out or can be ‘fiddled’ using an oven or hairdryer.
Spreadsheet (optional). Notesheets for each group. Workcards 2A, 2B, 2C, 2D. Overhead projector transparency.
Eight sets of apparatus (two for each activity), arranged around the room with their Workcards.
Spring balance, 100 g mass hanger, Three 100 g masses, Pulley and string.
Method of fixing string to base (see Workcard diagram). Workcard 2A.
One 100 cm3 beaker. Four other glass or plastic containers, all circular cross-section, all at least 100 cm3 in volume, of varying heights and diameters. Use straight-sided containers.
The five containers labelled with letters A to E, in order of their diameter, with narrowest A, widest E.
Water – this can be coloured with soluble food dye to make levels easier to see in containers.
Four sycamore, elder, or other large deciduous leaves which do not have a waxy coating, hung on a line (see diagram on Workcard 2C). These must be
prepared at least 5 days in advance. They are numbered 1 to 4, and then leaf 1 has Vaseline spread on its top surface, leaf 2 has Vaseline spread on its bottom surface, leaf 3 has Vaseline spread on both surfaces and leaf 4 has no Workcard 2C.
Five copies of Workcard 2D.