MnSTEP Teaching Activity Collection > MnSTEP Activities > Fluids in Motion: Introduction to Bernoulli

# Fluids in Motion: Introduction to Bernoulli

#### Summary

These in-class activities are geared toward the inquire of Bernoulli's Principle. Using different household items the students will be able to see how Bernoulli's Principle works for fluids in motion.

## Learning Goals

- Thinking outside the box of normal science
- Understanding the concept for the motion of fluids
- Learning vocabulary works for fluids

## Context for Use

This activity is best for the introduction of fluid in motion.
Split the class into small groups and have them move from station to station to study and learn what fluid in motion is all about.

Subject: Physics:Fluid Mechanics:Dynamics of Fluids
Resource Type: Activities:Classroom Activity

## Description and Teaching Materials

Below lists all the materials and the procedures for the 5 stations that need to be set up. Once done with the activities give the following notes (attached file).

Title - Introduction to Bernoulli's Principle
Primary Subject - Science
Secondary Subjects -
Physics Mini-Lab: Bernoulli introduction

Note from LessonPlansPage.com: This lesson plan contains references to a diagram that was not included. You may be able to replicate the diagram yourself, do without the diagram, or email the author and request a copy (email address is at the bottom of this lesson plan).
Notes: Safety precautions:
1) Never place the funnel directly in your mouth; make an "extension" to the narrow end of the funnel with your hand.
2) Never share straws.
3) The candle used in this experiment can be a fire hazard.

Basic premise of Bernoulli's equation:
Actual equation:

The Coanda effect:

Objective: Students will observe and document behavior of materials that undergo a change in fluid velocity nearby.

Materials:
-2 ping pong balls
-Straw for each member of the team
-2 books (supplied by the student)
-Funnel
-Paper cup
-Extra straw to use in the cup
-Water

Procedure:

Station #1: Take two books of about the same height and place them about 12 cm apart (2.54 cm = 1 inch). Place a sheet of paper over the gap between the books. Place your straw parallel to the plane of the paper but above the paper by 1 cm. Gently blow through the straw and observe. Now place the straw the same distance below the paper in the same orientation. Gently blow through the straw and observe.

Station #2:Place the two ping-pong balls at a distance of 2.54 cm apart on the table. Take your straw and gently blow a stream of air between the two. Put your ping-pong balls away in the designated place for the future station or lab group.

Station #3: Simulation of perfume "atomizer": Fill your cup of water. Use scissors to cut the straw at a point that is about 0.5 cm above the height of the cup as shown earlier. Use the marker at your station or table to mark off the height of the water INSIDE the straw before moving on with this experiment. Take the other straw and set it perpendicular to the straw in the cup according to the diagram on the board. Blow through the "other" straw and have an observer mark the new height of the water within the straw "sitting" in the water. *(This will be tough to do and you need to follow the instructions given to you at the beginning of class).

Station #4: Place the ping-pong ball in the funnel. Use the technique demonstrated at the beginning of class to "blow the ping-pong ball out" from the top as diagrammed on the board. Attempt to use the same procedure when the ping-pong ball/funnel system is upside down. Can you defy gravity with Bernoulli?

Station #5: Place a lighted candle behind a large can (I used a large Chunky Soup can) so that you cannot see the candle. Blow on the can and watch how the air will bend around the can (on both sides) to blow out the candle.
______________________________________

Analysis and conclusion:

Station #1:
1) What happened to the paper when you placed a velocity of air parallel and above it?
2) What happened to the paper when you placed a velocity of air parallel and below it?

Station #2:
3) Write Bernoulli's equation below and circle the variables that you witnessed in this experiment.
4) From the above equation, how did the variables observed affect one another? (i.e.: the buoyant force on an object is larger when a larger volume of fluid is displaced by the object).

Station #3:
5) Approximate your change in height of the fluid inside the "sitting" straw.
6) Name three examples of how Bernoulli's principle can be used in a device at home.

Station #4:
7) Why could you not "blow the ping-pong ball out"?
8) Did your team succeed in defying gravity? Draw a diagram of this station below and show force vectors.

Station #5:

9) What happened in this experiment? Why?

Conclusion:

1) Relate what happens when a large truck is passing your car on interstate 40.
2) Julie is riding in a car with her large family and, to her disgust, Grandpa lights up a cigar. The car is filled with smoke and finally Julie asks him to crack open his window. How does the pressure outside the car now relate to the pressure inside the car? What happens to the disgusting smoke particles? (two questions = two answers).
3) Use the diagram below to explain one reason why airplanes can fly. Use the words pressure, velocity and force as well as vector arrows. [file 'notes']

## Teaching Notes and Tips

These activites are very straight forward, and the materials are easy to find. Just make sure you have enough matches and ping-pong balls.

## Assessment

The questions/answers at the end of each station were recored in lab notebook and turned in at a later time.

## Standards

12.II.D.1-2: physics and motion