Energy, Machines, and Motion
Part Three: Motion
Lesson 18: Motion of a Fan Car
Students observe a fan car constructed of K’NEX™ pieces and a fan. Students will observe the car’s motion with the fan turned on and the fan turned off. Students will then calculate the speed of the fan car at different intervals as it moves along a two meter track.
Focus Question: What is motion? What causes motion? What is speed and how is it calculated?
3. Lesson Set-up and Management
EALR 2:
Inquiry
Core content: Questioning and Investigating
6-8 INQC Collecting, analyzing, and displaying data are essential aspects of all investigations.
EALR 4:
Physical Science
Core Content: Balanced and Unbalanced Forces
6-8 PS1A Average speed is defined as the distance traveled in a given period of time.
6-8 PS1B Friction is a force that acts to slow or stop the motion of objects.
6-8 PS1C Unbalanced forces will cause changes in the speed or direction of an objects motion.
- Students observe and describe the forces on a fan car and its motion.
- Students learn that when forces are unbalanced there will be a change in speed and motion.
- Students calculate the speed of a fan car’s average speed at different times as it moves along a path.
3. Lesson Set-Up and Management
Materials:
- Students use AA rechargeable batteries; make sure they are recharged before each class. Do not give students these batteries until the first part of lesson 18.1 is complete.
- Make sure the fans work before use with students.
- Have a place where fan cars can travel for 2 meters without running into obstacles.
- Have one car made before class as an example for students. Directions are also provided in the student edition. If you teach multiple classes there is no need to dismantle cars between classes.
- In Lesson 18.2 students will use adding machine tape to mark a track the fan car will travel along. Have students practice with their fan cars prior to timing, the position of the wheels will sometime cause the fan car to veer off to the left or right, you want the car to travel as straight as possible.
- Have students recognize that they want to keep their batteries as fresh as possible, so limit the amount of time they “play” with their cars.
- Check also to make sure the fan car moves freely, some students have experiences too much friction in the front axle causing their car to move very slowly.
Student Management:
- In Lesson 18.1 students are asked to collect and organize data regarding the motion of the fan car with forces of different strengths. As a class discuss different possibilities for their data table. Consider having measuring tapes for students to use.
- In Lesson 18.2 students work as a group of four to measure the
amount of time it takes the fan car to travel at different intervals
along a two meter track. Consider having the following jobs:
- Timer-will time all measurements
- Recorder-will record data for all trials and start the fan car for each test at the beginning of the track
- Monitor-will say start and stop for the timer as it moves along the track
- Retriever-will stop the fan car and move it back to the beginning of the track
- When students gather data they will start their fan cars always at 0.0 meters. They will start timing at different intervals. Being very clear regarding these directions will help students see the various speeds at different intervals.
- Students need to measure the speed of the car at different intervals. Students always start their car at 0.0 meters. Going over how they will measure will lead to greater student success.
- As a fan car moves along a two meter track, students will measure
the time it takes the car to travel 0.4 meters intervals. Consider
changing the 0.4 meter intervals of the two meter track to 0.5 meters
instead. You end up getting the same concept, but it could be easier to
time and to calculate speed for some students.
Writing Support:
- Students are asked to create a data table to collect information about how the fan car moves without a fan, when a push is applied to the car. The following data table is from a middle school student.
Data Table for Fan Car - Different Force Applied
- Students are asked in the Procedure of Lesson 18.1 to list the forces that are exerted on the fan car when it was pushed and after it was pushed. Consider using a diagram of the fan car before, during and after the push for students to label the forces acting on the car. This may provide them with a more focused example of forces acting at different times on the car. The following is an example used in one middle school class:
- Diagram above was made in Microsoft Power Point using notes page. This
gave students an opportunity to draw the forces and give their
thinking before, during and after the force was applied. The three
statements state:
- Where are the forces when the car is standing still?
- Where are the forces when there is an applied force?
- Where are the forces on the car after the applied force?
Reading Support:
- There are three readings for Lesson 18. The first reading will instruct students on how to calculate speed. This will be read at the beginning of the lesson. It is helpful to read this as a class to discuss the important concepts students will be using during the lesson.
- The selections after Lesson 18.2 “Propellers: Vehicles in Motion” shows different machines that use fan power. “Sailing Through the Solar System” describes uses of sail in both boats and space crafts.
Math Support:
- After reading Measuring Motion” students will calculate the speed in different situations in the Getting Started portion of Lesson 18. Students might benefit from several other examples to become more confident with this calculation.
- Students need to measure the fan car at different intervals along a track. Have students drop objects to practice timing. Students will average the trial data derived in Lesson 18.2 and will use the trial data to calculate the speed along different portions of the track.
Last updated 09/09/2009