TE Activity: Fun with Bernoulli
Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder
Summary |
Engineering Connection |
| Because they understand Bernoulli's principle, engineers manipulate air pressure in their designs to control and stabilize everything from rockets, to helicopters, to blimps. When designing airplane wings, engineers shape them so that they create lift. Even cars and trains are designed to take advantage of this principle, helping these moving vehicles stay on the ground at high speeds. |
Contents
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| Grade Level: 5 (4-6) | Group Size: 1 |
| Time Required: 35 minutes |
Activity Dependency  :None |
Expendable Cost Per Group
:
US$ .50 |
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| Keywords: airplanes, Bernoulli's Principle, force, pressure, velocity | |
| Reviews: Read Reviews | Be the First to Write a Review | |
Related Curriculum
:
| subject areas | Physical Science |
| curricular units | Up, Up and Away! - Airplanes |
| lessons | Can You Take the Pressure? |
Learning Objectives (Return to Contents)
Students should be able to:
- Understand that air pressure decreases as the speed of air increases.
- Understand that air pressure acts in all directions (not just down).
Materials List (Return to Contents)
Each student should have:
- 1 sheet of paper (new or recycled)
- 2 round balloons
- 2 pieces of string (18 inches long)
- 2 small plastic cups
- 2 straws
- 1 ping pong ball
- Water
Introduction/Motivation (Return to Contents)
When talking baseball, why does a curveball curve? Why does an airplane fly? The reasons can be found in Bernoulli's Principle, which states that the faster a fluid moves the less pressure it exerts. There are different air velocities on different parts of a curveball as well as on the different parts of an airplane. Bernoulli's Principle tells us that these differences in velocity mean there are differences in pressure as well. On a curveball, the difference in pressure causes the ball to move sideways. Engineers use their understanding of pressure differences to make airplanes fly.
Procedure (Return to Contents)
Before the Lesson
- Make copies of the Fun with Bernoulli Worksheet.
With the Students
Pass out the Fun with Bernoulli Worksheet.
Part A: The Paper Tent
- Have the students fold a piece of paper (lengthwise) in half and make a paper tent.
- Ask the students to predict what will happen when they blow into the tent. Will it appear to get larger, will it remain unchanged, or will it bend down toward the table? (Alternately, have students turn their paper tents upside down and blow through the V shaped paper.)
- Make sure the students notice that the tent flattens. This is because the air moving through the inverted V has less pressure, so the higher pressure on the outside of the paper tent flattens the paper.
- Have the students experiment with their paper tents, answer the relevant worksheet questions, and discuss their results.
Part B: Moving Balloons
- Blow up two balloons. Tie them off, and then attach a string to each one.
- Have students hold the two balloons together.
- Ask them to predict what will happen when they blow between the two balloons. Student should record their hypothesis in the space provided on the worksheet.
- Have students hold the balloons 4-6 inches apart and blow between them. If the students hold the balloons too close together, the balloons will simply move away from the student. The balloons must be sufficiently far apart so that students can blow between the balloons, not at the balloons.
- The students should see the balloons come together just like the paper V in Part A of the Procedures section.
- Have students complete the worksheet and discuss the results.
Part C: Magic Moving Ball
- Place two plastic cups about 6 inches apart.
- Place a ping pong ball in one of the cups.
- Ask the students to predict how to get the ball from one cup to the other without touching either the ball or cup.
- Have the students try a few of their ideas.
- Tell the students to gently blow across the top of the cup with the ball in it.
- The ball should jump from one cup to the next. This is because the air pressure moving across the top of the cup is less than the pressure inside the cup. The higher pressure inside the cup forces the ping pong ball to jump out of the cup.
- Have the students experiment with how far apart they can place the cups and still get the ping pong ball to jump from one to the other.
Part D: Bernoulli's Water Gun
- Give the students one cup filled with water and two straws.
- Have students place one of the straws in the water.
- Then students should cut the second straw in half to use as a "blower."
- Ask the students to predict what will happen if they blow across the top of one straw in the water with the other straw.
- Have students blow across the top of the straw with the other straw.
- The water should rise up in the first straw and blow across their table. This happens because the air blowing across the straw in the cup reduces the air pressure at that point. The normal pressure underneath pulls the water up the straw and the moving air blows the water out and across the room.
- Have students experiment with different straw lengths as the "blower."
Attachments (Return to Contents)
Troubleshooting Tips (Return to Contents)
Cut the string ahead of time to speed up the activity. Make sure there is a plan for the balloons after the activity is complete, as leaving the balloons with the students quickly becomes a large distraction.
Assessment (Return to Contents)
Pre-Activity Assessment
Discussion: Solicit, integrate, and summarize student responses.
- Ask students to review the Bernoulli Principle. Make sure everyone understands the concept. (The faster a fluid moves the less pressure it exerts.)
Activity Embedded Assessment
Worksheet: Have the students record measurements and follow along with the activity on their worksheet. After students have finished their worksheet, have them compare answers with their peers. Discuss as a class.
Post-Activity Assessment
Class Discussion: Have the students engage in open discussion to suggest solutions to the following problem:
- Given what we have learned, how does the Bernoulli Principle relate to airplane flight? (Answer: If air moves faster on one side of an object, the air pressure decreases and the object will move in the direction of the faster moving air. This is how wings create lift and why the objects in this experiment move in the direction of the faster air.)
Activity Extensions (Return to Contents)
Have the students look up "Bernoulli Principle" on the Internet and try to find an online demonstration of how the Bernoulli Principle works. A good site is: http://home.earthlink.net/~mmc1919/venturi.html.
Have the students blow between two empty soda cans (laying on their sides) with a straw. The cans should roll together just like the balloons came together. Do the students think this will work with any two objects? Have them investigate the answer and write a paragraph about what they find. (Most objects will do this unless they use objects that are too heavy for them to blow apart.)
Contributors
Tom Rutkowski, Alex Conner, Geoffrey Hill, Malinda Schaefer Zarske, Janet YowellCopyright
© 2004 by Regents of the University of Colorado.The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0226322. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.
Supporting Program (Return to Contents)
Integrated Teaching and Learning Program, College of Engineering, University of Colorado at BoulderLast Modified: September 26, 2008