Angular Speed of Ceiling Fan

Aim: To determine the angular speed of fan at different positions of the regulator knob.

Apparatus: Ceiling fan, stop watch


Have you ever wondered about the relation between the angular speed of a fan and the five step regulator knob. In this activity we will explore this relation. We have recorded the videos of a fan (in slow motion video mode of the smartphone) with regulator knob positions changing from 1 to 5. You are expected to generate the data from these videos and plot a graph between the angular speed of the fan and the knob position.


  1. From the videos given below, generate the data for angular speed of the fan at different regulator knob positions with 1% uncertainty in the measurement.
  2. Plot a graph between angular speed of the fan and the regulator knob position.
Regulator Knob 1
Regulator Knob 2
Regulator Knob 3
Regulator Knob 4
Regulator Knob 5

3. You can also download the videos by clicking on the links below:

a. Knob 1

b. Knob 2

c. Knob 3

d. Knob 4

e. Knob 5


In order to get your response, we are providing you with a google form. So that, we can get an idea about

  1. your data collection techniques,
  2. variables chosen for measurements,
  3. your data and
  4. the graphs that you will plot.

The google form:

Use spreadsheet for calculations, if needed: spreadsheet

Download the graph sheet given below to plot the graph: Graph Sheet


What is meant by 1% uncertainty in the measurement of data?

When we say that we want to measure a variable, y with 1% uncertainty, it means that

It means that the measured quantity is at least 100 times the least count.

Extra Work:

Repeat the same procedure for the ceiling fan at your home and plot the graph between the angular speed and knob position. Is there a change in the nature of the graph?

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