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2.5

Minor Versionm

by Vishal Bhatt

Introduction

Using just a couple of straws of different gauge, we create a wonderful propeller, which addresses many concepts in physics.

Video Overview

    • Handle scissors with care.

  1. Take a 10 cm fat straw and bend it into half. Nip the two corners at the centre-fold using scissors. This would give you two diamond shaped holes in the middle of the straw.
    • Take a 10 cm fat straw and bend it into half.

    • Nip the two corners at the centre-fold using scissors.

    • This would give you two diamond shaped holes in the middle of the straw.

    • Ensure that the holes are big enough so that the normal straw can be inserted easily, but not so big that the straw breaks in half.

  2. Press down each end of the fat straw and seal them with tape. Tape over the end of the straw rather than around it, such that the tape doesn't come off. The orientation is very important. In other words, when you look through the diamond shaped holes, both taped ends should look flat to you, i.e. press the back and front and tape the ends.
    • Press down each end of the fat straw and seal them with tape.

    • Tape over the end of the straw rather than around it, such that the tape doesn't come off.

    • The orientation is very important. In other words, when you look through the diamond shaped holes, both taped ends should look flat to you, i.e. press the back and front and tape the ends.

  3. Nip one corner using scissors on each taped end of the fat straw such that they are diagonally opposite to each other. Nip one corner using scissors on each taped end of the fat straw such that they are diagonally opposite to each other.
    • Nip one corner using scissors on each taped end of the fat straw such that they are diagonally opposite to each other.

  4. Fold one end of the normal straw about  5  mm  from the edge. Nip just one corner using scissors so that you get a diamond shaped hole close to one end of the straw. Nip just one corner using scissors so that you get a diamond shaped hole close to one end of the straw.
    • Fold one end of the normal straw about 5 mm from the edge.

    • Nip just one corner using scissors so that you get a diamond shaped hole close to one end of the straw.

  5. Insert the normal straw into the diamond shaped holes of the fat straw such that the hole in the normal  straw lies within the fat straw. Shut the hole-end of the normal straw with your finger and blow through the other end of the normal straw. Shut the hole-end of the normal straw with your finger and blow through the other end of the normal straw.
    • Insert the normal straw into the diamond shaped holes of the fat straw such that the hole in the normal straw lies within the fat straw.

    • Shut the hole-end of the normal straw with your finger and blow through the other end of the normal straw.

    • Your straw propeller should now spin!

    • On changing the direction.

    • The fat straw doesn't rotate smoothly -

    • Increase the size of diamond shaped hole.

    • The fat straw doesn't rotate at all -

    • Ensure that its ends are taped correctly. The orientation is very important. In other words, when you look through the diamond shaped holes, both taped ends should look flat to you, i.e. press the back and front and tape the ends.

    • Ensure that the two holes made, are diametrically opposite to each other.

    • Ensure that the diametrically opposite holes are large enough for the air to pass through.

    • Ensure that the hole in the normal straw is not more than 5 mm from one of its ends .

  6. Vary the length of the fat straw (double, half etc) and observe its effect on the speed. Vary the number of holes and observe its effect. Make a hands-free propeller.
    • Vary the length of the fat straw (double, half etc) and observe its effect on the speed.

    • Vary the number of holes and observe its effect.

    • Make a hands-free propeller.

    • Make a propeller using straws of the same gauge.

    • Make a hands-free multi-rotor propeller.

    • To learn and make these variations, please go to Action Reaction - Straw Propeller (Variations).

Finish Line

Suhail Ahanger

Member since: 05/02/2017

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