Acceleration and the Measurement of Acceleration
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Subject: Physics |
Date: |
Teacher: |
Title: Acceleration and the measurement of acceleration
Central Concept: Plotting and recognizing acceleration in motion plots
Learning Standards (National Science Education Content Standards):
B.4 - Motions and forces
A.1.4 - Formulate and revise scientific explanations and models using logic and evidence
A.1.1 - Identify questions and concepts that guide scientific investigations
Essential Questions:
What is acceleration?
What is the relationship between speed and acceleration?
What is the relationship between acceleration and position?
How can we measure the change in position of something that happens very rapidly?
Content and Skills:
Develop a mathematical understanding of acceleration(B.4)
Understand methods for taking measurements of acceleration(B.4)
Scientific inquiry and reading comprehension (A.1.4, A.1.1)
Learning Activities:
- Get students' definition of acceleration. What are the related concepts? Position, speed, velocity, time, distance...
- Show video of lizard jumping. (link)Is the lizard moving?
- How is the motion of the lizard changing?
- Does the speed stay constant or does it change? When does the speed change? Does the speed change when the lizard is in the air?
- Looking at the Distance versus time graph can we tell something about the motion of the lizard?
- Velocity: What does a distance versus time graph of of a body moving at a constant velocity look like
- On the board create a distance versus time graph of a object moving at a constant velocity. Example: plot a distance time graph of a car traveling at 50 mph for 4 hours.
- Now what if we plot a velocity versus time graph? What does that look like?
- Can we create a velocity versus time graph of the lizard jump data?
- We can calculate the average velocity for a given motion if we know the distance traveled and the elapsed time.
- The distance and time information for the lizard jump is available either from Tracker or from the Graphing assignment from the previous class.
- With this data we can compute the average velocity from one frame to the next. Work through a couple of steps from the lizard jump worksheet.
- Using data from Tracker and a spreadsheet program this velocity versus time graph data was created.
- We can calculate the average velocity for a given motion if we know the distance traveled and the elapsed time.
- How does the velocity change over time?
- Does the velocity time graph look like what one would expect from watching the lizard jump video?
- Acceleration: What does a velocity versus time graph of a body undergoing constant acceleration look like?
- On the board create a sample velocity versus time graph of an object experiencing constant acceleration.
- Example: Plot a velocity time graph of a ball being falling from a building for 2 seconds.
- Now what if we plot a acceleration versus time graph? what does that look like?
- Can we create a acceleration versus time graph of the lizard jump data?
- We can calculate the average acceleration for a given motion if we know the change in velocity and the elapsed time.
- The velocity and time information for the lizard jump is available from the graphs created previously.
- With this data we can compute the average acceleration from one frame to the next. Work through a couple of steps from the lizard jump worksheet, the remaining steps can be completed as homework.
- Using data from Tracker and a spreadsheet program this acceleration versus time graph was created.
- We can calculate the average acceleration for a given motion if we know the change in velocity and the elapsed time.
- How does the acceleration change over time?
- Lets look at a graph showing distance velocity and acceleration.
- Can we draw some conclusions about the graph? Note: Noise in the data is amplified when we go from the distance, to the velocity, and finally to the acceleration versus time graph. This lead to greater uncertainty.
- On the board create a sample velocity versus time graph of an object experiencing constant acceleration.
Equipment / Materials:
Internet access – projector or computer lab
Expected Outcomes:
Students should:
- Understand difference between graphs representing distance, velocity, and acceleration
- Understand how to determine acceleration from a velocity versus time graph
- Understand that uncertainty tends to increase as we measure the slope of a graph.
Assessment / Assignment(s):
Homework:
Using the data from the previous homework assignment where the velocity and position of the jumping lizard was meassured, calculate and plot the acceleration of the lizard versus time.
