Arc-o-Bot #1

Aim: studying the relationship between circumference radius and length of a circumference arc subtended by a given angle; direct proportionality.

Material:

OZOBOT

Card with Path an example is provided

In this activity students will experience that, for a given angle, the ratio between radius and length of a circumference arc is constant. The length will be measured as time OZOBOT takes to cover the circumference arc.

Procedure:

• STEP 1

Write a code for following a line at a defined speed.

Set a velocity and upload the code on OZOBOT.

Measure the time OZOBOT takes to cover a circumference arc, repeating the measurement in order to minimize the error.

Repeat the same procedure on other circumference arcs: take note also of the different radius.

• STEP 2

Calculate the ratio between radius and arc length: it should be the same for all arcs (check if they are all subtended by the same angle!).

Extensions:

• OZOBOT’s led can flash with different colours, so the measuring of the time becomes easier.