Task 1: Make a dynamometer for measuring the tension force

Tie a rubber (so-called food) hose approximately 3 meters long with one end to a strong object (for example, to a radiator). On the other end of the hose, you can tie a short rod as a handle. Draw a mark on the hose roughly in the middle. Place a table with a large sheet of paper to draw a scale on or record the performances of individual pupils under the hose at the point of the mark (Fig. 7). Now you can organise a competition in who applies the greatest tension force. The friction force between the floor and the shoes limits this force. You can measure the differences in the tension strength of a barefooted and a pupil with his/her shoes on, on a dry and wet floor, on a different surface, or on a tension force if the pupil can be propped against a fixed stop.