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

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

  3. 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.
    • 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.

  4. 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.
    • 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.

  5. 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.
    • 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.

  6. 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.
    • 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.

  7. Bring all the cotton threads together, without tangling them. Twist them together at their tip.
    • Bring all the cotton threads together, without tangling them.

    • Twist them together at their tip.

  8. Insert the  threads into the ring magnet. Make a tight knot.
    • 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.

  9. 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!
    • 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.

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