Task 25

Materials and tools for a working group:

board, wooden block, ruler, plasticine, rough materials (eg fleece, sandpaper)

In another task, pupils investigate whether the magnitude of the frictional force that acts against the movement of an object on a surface depends on the quality (properties) of the surface. This relationship was examined in task 19 by measuring the distance from which the magnet attracts a clip lying on different surfaces, so this task can be perceived as verifying the result obtained by solving the 19th task. If the pupils did not carry out the task of 19., the research question is inductive for them, ie. the goal is to identify (not confirm) whether the relationship between the two variables exists and if it has a character (what surface properties cause a reduction and what friction increase).

Pupils use the same procedure as in the previous two tasks to verify predictions. For investigation they use a wooden cube sliding along a wooden board. In the first situation, they let the block slide over the board, in the second situation they cover the board with a rougher cloth (such as fleece, sandpaper, etc.), and in the third situation, the material is glued not only to the backing on which the slip block, but also to the cuboid surface by which it is laid on the mat. For each situation they repeat the measurement three times to avoid measurement errors and conclude on the basis of the data obtained.