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Rockets!

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What makes a rocket fly?

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Action and Reaction

What about a...

    • Plane?
    • Submarine?
    • Car?
    • Person jumping?

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Newton’s Third Law

    • For every action, there is an equal and opposite reaction
    • Rocket push hot gas down
    • Hot gas push rocket up

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Action and Reaction

Newton’s Third Law applies to everything!

When we jump...

  • We push the earth down...
  • ...and the earth pushes us up!

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Water Rockets

  • Uses air pressure to push water out
  • Works just like a real rocket! (...but with water instead of hot gasses)

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Parts of a Water Rocket

  • Water (demo)
  • Body
  • Fins (experiment)
  • Nose
  • Launcher

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Water

Pop Quiz:

Why do we need water?

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Light and Heavy (Demo)

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What did we learn?

  • When we throw a...
    • Light object: Very little force
    • Heavy object: Much more force
  • If the rocket only contains air, then it will not fly well because air is very light
  • What if the rocket only contains water?

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Parts of a Water Rocket

  • Water (demo)
  • Body
  • Fins (experiment)
  • Nose
  • Launcher

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Body

IMPORTANT! Only use gassy drinks bottle (eg. Coke, Pepsi, Sprite)

Other types of bottles (eg. mineral water, green tea) are NOT designed to withstand pressure and will explode when pressurized

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Fins

Why do we need fins?

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Why we need fins

  • Helps to stabilize the rocket
  • Without fins, the rocket will tend to tumble
  • Should be placed near the back

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Fins

  • You can have any number of fins (eg. 2, 3, 10)
  • ...but 3 or 4 is recommended

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Fins

Experiment and test out different...

  • Fin designs
  • Fin placement (front, middle, back)

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Testing Fins

  • Test your fin design using the fan and 2D rocket
  • If the fin is good, the 2D rocket should stay straight

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Experiment Time

Collect

  • Scissors (share please!)
  • Plastic board (half piece each)

Do

  • Draw your fin design on the plastic board
  • Cut it out and test it at the fan

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Nose

  • Bottle and fin are light
  • Will fly very fast at launch...
  • ...but light objects contains very little kinetic energy
  • Will lose speed rapidly

This will fly, but not very well...

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Nose

  • Use a tennis ball as the rocket’s nose
  • Increase weight
  • Slightly improve aerodynamics

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Launchers

3 main types of water rocket launchers

  • Simple Launcher
  • Launch Ramp
  • Launch Tube

What does it do?

  • hold the rocket while air is pumped in
  • then release it so it can fly

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Launchers

simple

launcher

launch

ramp

launch

tube

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Simple Launcher

  • Rocket is unsupported
  • OK for vertical launch
  • Tends to fall over when launched at an angle

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Launch Ramp

  • Rocket is supported by a ramp
  • Otherwise the same as a simple launcher
  • Can launch at an angle

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Launch Tube

  • Tube is inserted into rocket
  • Can launch at an angle
  • Tube guides the rocket keeping it straight
  • Tube also provides a boost at the start (Why?)

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Safety Rules

  • Only launch when permission is given
  • Do NOT launch if there is anyone down range
  • Do NOT enter the range if any launchers are loaded
  • Never stand in front of a loaded launcher
  • Do NOT launch the rocket vertically upwards

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Launch Time!

  • Time to test out your rockets!
  • You will decide what to vary, such as...
    • Launch angle
    • Pressure (max of 3 bars)
    • Amount of water

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  • Created by A Posteriori LLP
  • Visit http://aposteriori.com.sg/ for more tips and tutorials
  • This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
  • Some vector art created by freepik - www.freepik.com

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