Investigating Motion - Graphing Speed
Summary
In this introduction to motion activity, students will get a personal understanding of speed and acceleration by experiencing it firsthand. Wheeled office chairs or other cart like devices are used to give one student a ride as a fellow student uses a rope with a spring balance attached to apply a steady force to the rider. Data to be collected includes the distance traveled, time, force, and average speed. Students will record information on a data table and then create a graph with which they compare and interpret different outcomes. They will also predict outcomes when variables are changed. The intention of this activity is to promote interest and conversation with students about speed, velocity and acceleration.
CollapseLearning Goals
This activity is designed as a beginning physics activity where students will study speed, measure and record time and distance, then graph results. Learning goals: To collect data and create, compare and interpret graphs. To predict outcomes when variables are changed. Key Concepts: Speed requires both time and distance. When the driving force is increased on a moving object the speed increases. When the mass of a moving object increases, the speed decreases.
Vocabulary words: Force, Constant
Vocabulary words: Force, Constant
Context for Use
For 6th to 8th graders, this activity can be used as an introduction to speed and acceleration. If a hallway is used outside the classroom, one group at a time can collect data while others are working on different activities. If you do this in spring or fall you may be able to use the gym and have all students do this at once.
Instead of wheeled chairs the ambitious can put together carts using skateboard or roller skate wheels mounted to 16" squares of ¾ inch plywood sheets.
Instead of wheeled chairs the ambitious can put together carts using skateboard or roller skate wheels mounted to 16" squares of ¾ inch plywood sheets.
Description and Teaching Materials
In preparation, review accurate data collecting and graphing (Mention that "time" is usually on the horizontal axis...chart needs title, labeled axes...) What is speed?
Set Up: On a flat surface (hallway or gym) measure and mark with masking tape the 0, 5, 10 and 15 meter distances
Group Materials:
Wheeled device (wheeled office chair or modified cart)
Spring scale
Tow rope
Stopwatch
Notepaper with data charts
Graph paper
Each group will be graphing the speed of a student over a distance of 15 meters where a constant force is applied to the student.
Each group will have: one person pulling, one being pulled (on chair or cart) a timer calling out seconds, and a spotter/recorder to listen and record the exact moment the student reaches the 5, 10, and 15 meter marks. Also record the amount of force used.
Pullers must take care to use the same force throughout the distance by self-monitoring with the spring scale.
Once all students have ridden, each student will graph their own data of distance vs time.
Student Questions:
· How does your graph compare to others in your group? (Notice differences and similarities)
· Sketch a prediction of how a graph would look if your weight was doubled. Why?
· Sketch a prediction of how a graph would look if the constant pulling force was increased. Why?
· What would the graph look like if the pulling force was only applied for the first three seconds? (try this if your group has time)
· Imagine you have started another "ride". What would have to happen for your "ride" to produce a horizontal line between the 5 and 10 meter mark on your graph?
· How would you interpret a graph where the slope of the line is going down?
· Calculate and record your average speed at 5, 10 and 15 meters. Are you traveling at the same speed throughout your ride?
· Predict what your chart would look like if your ride went to 20 meters.
Set Up: On a flat surface (hallway or gym) measure and mark with masking tape the 0, 5, 10 and 15 meter distances
Group Materials:
Wheeled device (wheeled office chair or modified cart)
Spring scale
Tow rope
Stopwatch
Notepaper with data charts
Graph paper
Each group will be graphing the speed of a student over a distance of 15 meters where a constant force is applied to the student.
Each group will have: one person pulling, one being pulled (on chair or cart) a timer calling out seconds, and a spotter/recorder to listen and record the exact moment the student reaches the 5, 10, and 15 meter marks. Also record the amount of force used.
Pullers must take care to use the same force throughout the distance by self-monitoring with the spring scale.
Once all students have ridden, each student will graph their own data of distance vs time.
Student Questions:
· How does your graph compare to others in your group? (Notice differences and similarities)
· Sketch a prediction of how a graph would look if your weight was doubled. Why?
· Sketch a prediction of how a graph would look if the constant pulling force was increased. Why?
· What would the graph look like if the pulling force was only applied for the first three seconds? (try this if your group has time)
· Imagine you have started another "ride". What would have to happen for your "ride" to produce a horizontal line between the 5 and 10 meter mark on your graph?
· How would you interpret a graph where the slope of the line is going down?
· Calculate and record your average speed at 5, 10 and 15 meters. Are you traveling at the same speed throughout your ride?
· Predict what your chart would look like if your ride went to 20 meters.
Teaching Notes and Tips
This is my first time teaching physics and can only guess as to what challenges may come up. The method of stopping the rider including avoidance of crashing into walls and other students will need to be discussed before hand.
Assessment
This is a beginning activity from which I will build on. As the goal is mainly to stimulate interest for further examination I will assess with a notebook check of the activity, including a look at the students data chart, graph work and answers to student questions. I will also challenge students with sketches of graphs for students to interpret and encourage class discussion.
Standards
D. MOTION: The student will measure and graph the positions and speed of an object