Subject Covered:  Science
 

Grade Range: 6-8
 

Learning Objectives:
 
Students will have the opportunity to:

• Understand Bernoulli's Principle and how air pressure affects a plane's ability to fly.
   

Standards List:
 
(From McRel Standards, www.mcrel.org/compendium/browse.asp)
 
Science Standards -- Physical Sciences
Understands forces and motion

• Understands general concepts related to gravitational force
• Knows that an object's motion can be described and represented graphically according to its position, direction of motion, and speed
• Understands effects of balanced and unbalanced forces on an object's motion
   

Tools and Materials:
 
Strips of paper, ping pong balls, string or yarn, text books, beach ball, an electronic fan, and straws.
  

Time Needed:
 
One class session is recommended to complete the lesson.
 

Teaching Strategy:
 
Solicit ideas from students about how a plane flies. How is it similar or different to how birds fly? Ask the students to brainstorm ideas about how flight works and write down their ideas on the chalkboard. After soliciting students' input, begin a discussion of Bernoulli's principle. Describe how lesser air pressure over the top of a surface creates lift. Discuss how this principle applies to flight and how it enables planes to fly. When air moves over the greater surface area of the top of a curved wing, the air has to move more quickly, creating less air pressure than the air traveling under the flat surface of the bottom of the wing. This difference in air pressure creates lift, allowing planes to fly.
 
Before beginning the discussion, you may even wish to screen for the class the segment on the Wright Brothers' first flight (timecode: 2:10 - 10:50) from episode 1 of "Chasing the Sun."
 

Activity:
 
Students will perform three short activities, followed by a class demonstration. After each activity, have the students make entries into their class journals or on a sheet of paper about the results of their experiments. Have them write down how their results reflect the different principles of flight you've introduced.
 
For the first activity, give the students thin strips of paper (about 2 inches by 8 inches). Instruct your students to hold the strips of paper up to their mouths. The students should position the strips of paper just below their mouths. While the top edge of the strip of paper should be held horizontal just below their lips, the bottom part of the strip of paper should hang down vertically over their chin. Instruct your students to blow air straight out over the top of the strip of paper. Have them observe what happens and make notations in their journals about what happened and how it relates to principles of flight.
 
Tape a piece of yarn or string onto each of two ping pong balls. Have the students hold the strings together at about eye level so the ping pong balls rest at mouth level. Blow air straight forward in between the two ping pong balls. What happens to the ping pong balls? Why? Observe what happens. Instruct students to record information into their journals.
 
Have the students take another ping pong ball and a straw. Instruct students to place the straw in their mouth and tilt their heads backward. Have them attempt to blow air into the straw in an attempt to balance the ping pong ball on top of the straw with the air pressure. The students can record data regarding the length of time that they can support the ping pong ball. Students should make a journal entry about this activity.
 
The last activity can be done as a class demonstration: Take a large "box" type fan, turn it on its highest setting, and turn the fan on its side so that the fan is horizontal. . Place a beach ball into the air stream and keep it balanced, just as the students did with the straws and ping pong balls. While holding the fan, begin to walk around the room. The ball will remain in the air stream. Have the students record entries into their journal.
 
Complete the class activity with a discussion. Ask the students about the results of their activities. What forces of flight have they witnessed with their activities? How does that relate to principles of flight they've been learning. Students should comment on the data that they have collected in their journal entries.
 
The students can be evaluated during the follow up class discussion. The students can turn in their journal entry for this topic and they can be evaluated for effort, teamwork and contribution to group work situations.
 

Extension:
 
Contact your local airport's air traffic control office and invite a spokesperson to come tell students about their role in aviation. Follow this lesson with a discussion of turbulence in the air. Look at the effects of large planes taking off at local airports.