2. Theoretical and experimental capsule on the circle

3. Properties of the circle

4. Exercise Find several round objects and measure their perimeter How did you go about measuring round objects? Is this method precise?

5. Exercise How to measure an irregular roundish object? Is it easy? Do you know of an instrument to measure that kind of shape?

6. The Odometer www.nouveauxobjets.com

7. Principle of the map odometer Description of the principle The wheel rolls on the map and allows you to accurately follow an outline or course. Using the reference indicator, it allows you to add up the number of kilometres traversed. Usually it is subdivided into equal parts in relation to the scale.

8. Principle of the map odometer (continued)

9. Analysis of the technical object With what is it made? How does it work? What are the scientific principles that explain the function of the odometer? Where are (is) the force(s) that act on the object? Do they cause movement? How is the movement transmitted?

10. Function Force Handle Wheel Axle

11. Forces I must push… Movement …so that the wheel of the odometer turns. Scientific principles I must push… Movement

12. What is a wheel? It is a simple machine The wheel was created long ago. It is used to circulate without there being too much friction. Friction is where two surfaces rub together. It is also a part of many objects (the pulley, the gear, the friction wheel). It is, in a way, composed of a series of levers laid out over 360° where the support point is the axle of the wheel.