Micrometry using Foldscope

A workshop named “Magnify Your Curiosity-Mathematics in a Laboratory with Foldscope” was organized by Department of Environmental Science, University of Calcutta on the evening of 12th March 2019 at Jagadis Bose National Science Talent Search, Kolkata, West Bengal, India, in collaboration with Howrah Vigyan Chetna Samannaya.

Map showing route of Jagadis Bose National Science Talent Search, Kolkata, West Bengal, India

Introductory Session-

The workshop started with Dr.Punarbasu Chaudhuri delivering a speech on Relative Size of Things and metric conversion of different units of length.

Interaction with students at introductory session by Dr. Punarbasu Chaudhuri

Introducing the macroscopic measuring tools-

After the introductory session, Dr. Punarbasu Chaudhuri demonstrated different length measuring devices such as Measuring tape, Ruler Scale, Vernier Scale, Screw Gauge their applications and limitations too.

Measurement session-

Dr. Punarbasu Chaudhuri demonstrating screw gauge to the participants

In this session, students were asked to measure the length of a table with Ruler Scale and as well as a Measuring tape. The measured value was noted down and the difference in values between two instruments was shown to describe the human error.

participants measuring the length of table

After this participant were asked to measure the thickness of their hair with a ruler scale. The measurement was done by coiling a single strand of hair around a plastic refill and measuring the total length. After this, the total length measured by ruler was divided by the total number of coils to get the value of a single hair strand.

Participants spinning a single hair strand to measure the width of single hair strand

Measurement of single hair strand using foldscope-

In this session, Stage Micrometer was introduced to the participants and by calibrating stage micrometre with a ruler scale (centimetre scale) we determined the width of a single strand of hair. It was also done at various portion of hair to get the range of the width of human hair.

Dr. Punarbasu Chaudhuri describing the Stage micrometer and about the length of a single division of stage micrometer
Interactive session with foldscope- A. Ranjan Demonstrating how to attach foldscope with a smartphone, B. Participants observing under foldscope

Measurement of stomata-

A fresh leaf peel was taken on a slide and the length and breadth of stomata was measured using foldscope.

Demonstration of measurement of length of stomata after calibration with stage micrometer


During measurement using foldscope, the original images taken by a single smartphone has to be original images and not zoomed or cropped.


This was their first exposure to micrometry using foldscope and the event was a success.

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