Made by Manish Kumar.
"Look down at the veins tracing their way up your fingers. They are made of stardust. This is a truth rooted purely in science, one of the many that make the subject beautiful to me. However, it is a shame most science students will not realise this during the course of their studies. What could have been a passion for astrophysics becomes instead distaste for formulae of elliptical orbits students are unable to fully comprehend. Were I to change the way science is taught in institutes, I would encourage appreciation for the implicit over memorisation of the explicit, nurture understanding and curiosity for derivations over worship of formulae, and demonstrate practical applications to clarify ambiguous theory." - Sahr Jalil 2011
My friend Sahr, wrote this for our team's evaluation form to LUMS PSIFI 2012. The question was, "How would you change the way science is being taught in institutes?"
Science cannot be taught just based on theory, but it needs to be taught based on observation, something formula and rote-learning cannot teach. And this example, is perfect to reflect over this thesis.
Step 1: Definition
An Aeroplane relies on Bernoulli's Principle to generate lift on its wings.
A Helicopter uses the same method to generate lift on its wings.
A Race-car uses Bernoulli's principle to stay on the ground (down force).
An Insecticide Spray also uses Bernoulli's Principle to spread out the spray over a larger area.
A Bunsen Burner
Ping Pong Ball Experiments
Lets first look over one practical application and then demonstrations and then more practical applications. :)
Step 2: Practical Application : Airplane and Helicopter Wings
Step 3: Demonstrations : Paper Airplane
Everyday, someone designs a new paper airplane but not every plane is able to fly properly and go higher using Bernoulli's Principle. After bending a piece of paper into the respective folds, we are supposed to get a plane that it thicker from the front and thinner from the end. This helps to give the paper plane better lift.
Another Way of demonstrating this experiment is to make two paper airplanes of the same paper and structure and then cutting one from the ends as shown in the pictures.
Airplane 1 : No cutting.
Airplane 2 : Cutting
We notice that Airplane 2 actually lifts and then lands showing a parabolic curve. Airplane 1 just shows a downward movement.
Step 4: Demonstrations : Blowing Over Paper
A stream of air over the paper creates a low pressure zone which lifts the paper due to the pressure difference: higher pressure under the paper and lower pressure over the paper. This levitates the paper in the air.
Step 5: Demonstrations : Tissue Paper Hair Dryer or Leaf Blower
Slip a thin rod through the hole in a toilet tissue paper role. Have one person hold the rod by placing a hand on each side of the toilet paper roll. Then switch on the blow dryer and watch the magic. This is Bernoulli's Principle which lets the tissue paper fly high up in the air without falling.
Step 6: Demonstrations : Ping Pong Ball Experiment 1
A ping pong ball can be "floated" on a stream of air. The air rushing around the ball creates a pressure low enough to lift and support the ball. Even when the ball is not exactly over the air source! As long as the low pressure spot is under the center of mass of the ball, it will stay "afloat". And the high pressure regions around the ball push the ball in if it tries to escape the low pressure zone.
We can repeat the same experiment using a balloon using a lower blow dryer power.
Step 7: Demonstrations : Ping Pong Ball Experiment 2
In this experiment, we need to create two types of funnels. One will be a cylinder of the exact same radius of the ping pong ball itself and the other will be made in a cone shape. We now need to place the ping pong ball in both funnels and blow out from one end. The ping pong ball shoots out from the cylinder but not the cone shaped funnel.
When the ping pong ball is placed in the cone shaped funnel with the air blowing out, the ball won't fall out of the funnel. The rushing air creates an area of low pressure that holds the ball in place.
Step 8: Demonstrations : Boomerang!
Step 9: Demonstrations : Envelope
Step 10: Practical Applications : Race Car
Step 11: Practical Applications : Insecticide Spray
Step 12: Practical Applications : Bunsen Burner
The mixture of gas and air enables the gas to burn completely to produce a clean, hot, and smokeless flame.