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Minor Versionm

by Vishal Bhatt

Introduction

Using plastic sheets of different sizes to make a parachute, you can show how the area of a surface affects air drag/resistance and how various objects in nature use this principle to their benefit.

Video Overview

    • Handle scissors and cutter with care.

  1. Cut the bottom of the plastic bag and spread it open.
    • Cut the bottom of the plastic bag and spread it open.

    • Cut between the two layers on both sides so as to get two separate pieces of plastic.

    • Cut a 20 cm x 20 cm square out of one of the plastic sheets using a ruler and cutter.

    • Take the 20 cm x 20 cm plastic sheet.

    • Fold AB over CD to make a rectangle.

    • Now, fold QS over PR to make a square.

    • Overlap vertex L with vertex O.

    • We have a right angled triangle ABC.

    • Fold the side AB towards the hypotenuse AC. Now you get one small and one big triangle.

    • Cut along the line BQ.

    • Open the plastic sheet. This makes the canopy of our parachute.

    • You have essentially made a 16-sided polygon, with slightly curved edges, making it look almost like a circle.

    • As you open the triangle, you'll find the 8 creases (16 `corners'); here we have marked every alternate crease line to identify 8 evenly spaced locations along the edge of the parachute.

    • Place eight cotton threads ( 25cm each) at the edge of the creases.

    • Stick them using a tape.

    • Bring all the cotton threads together, without tangling them.

    • Twist them together at their tip.

    • Insert the threads into the ring magnet.

    • Make a tight knot.

    • You could use any ring shaped object of appropriate mass, e.g. a nut or any weight, e.g. a stone, which you can tie easily to the strings.

    • Repeat all the previous steps to make a parachute of a different size i.e using a 40cm x 40cm plastic sheet.

    • Hold the parachute as shown in the figure.

    • Drop the parachutes from a sufficient height (e.g. terrace or balcony of a 1 or 2-storey building) and watch them descend!

    • The payload is too heavy or too light for the canopy.

    • Strings are unequal in length or not attached properly.

    • Release both parachutes from the same height at the same time. Record the time taken by each to touch the ground.

    • Double the weight on each parachute and measure the time taken to descend the same height.

    • Measure the surface area (and mass, if possible) of each parachute, and its average velocity in each of the cases.

    • Use 4 suspension lines instead of 8 and then record the time taken by the parachutes to touch the ground. Compare it with your previous observation.

Finish Line

Vishal Bhatt

Member since: 04/26/2017

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