Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
As a result of this lesson students should be able to:
- Identify changes in motion that produce acceleration.
- Explain why circular motion is continuous acceleration even when the speed does not change.
- Calculate acceleration as the rate at which velocity changes.
- Graph acceleration on a velocity-time graph.
- Define instantaneous acceleration.
Prior Knowledge: What prior knowledge should students have for this lesson?
At the beginning of this section students should know:
- Motion is described as a change of position in relation to a frame of reference.
- The distinction between speed and velocity.
- Simple vector operations as addition and subtraction.
- How to identify positive and negative integers on a number line.
- Graphing Skills: Student should be able to identify the slope and its meaning in a linear graph.
- Basic Algebra skills: How to calculate or determine areas of rectangles and other type of operations.
Be aware of a common student misconception: If an object is accelerating then the object is speeding up. Explain to students that this is true in a common, everyday usage. But in scientific terms, acceleration refers to any change in velocity. Velocity is a vector including both speed and direction, so acceleration can be speeding up, slowing down, or even just changing direction.
Guiding Questions: What are the guiding questions for this lesson?
The Guiding Questions will include the following:
- How are changes in velocity described?
- How can you calculate acceleration?
- How does a velocity-time graph indicate acceleration?
- What is the meaning of the area under the graph in a velocity-time graph?
- When is an object moving with constant acceleration?
- What is instantaneous acceleration?
Teaching Phase: How will the teacher present the concept or skill to students?
The concept of acceleration will be presented using an inquiry format. The teacher will do an opening demonstration:
- Let a ball roll down an inclined rail and ask students for observations. Record all observations. To proceed, they must mention something to the effect that the ball speeds up as it rolls down.
- To obtain a more detailed description, ask students which observations are measurable. Make sure they include the observation that the ball speeds up as it rolls down the rail. (Do not let them state the ball accelerates since we haven't defined acceleration yet!)
- Ask students how they could measure speed directly. Lead them to the conclusion that they cannot, but that they can measure position and time.
- Students should mark the position of the object at equal time intervals.
- Time should be plotted as the independent variable.
- The teacher can demonstrate this concept with a variety of constant acceleration motion examples such as a cart rolling down a track, a bowling ball rolling down an access ramp, or a disc and axle rolling down a ramp of two parallel pieces of conduit pipe.
- Timing variations could include using photo-gates, water clocks, pendulums and metronomes in addition to stopwatches.
- Make sure that the angle of inclination is less than 30 degrees.
- Initial position and speed must be zero. (See sample graphs below.)
The teacher should discuss experimental procedure and the verbal interpretation of the parabolic x-t graph. Students should be able to describe that the displacement during each time interval increases over the previous time interval. Since the object travels greater distances in each successive time interval, the velocity is increasing. Define Acceleration as a change in speed or velocity (increasing or decreasing) at a time interval. The teacher should present at this time a perfect example of acceleration due to a change in speed or velocity--free fall: the movement of an object toward Earth solely because of gravity.
Students should have also written an expression for the straight-line graph: x = kt2 + b, where b --> 0. The units of the constant of proportionality (slope) are m/s2, but k is not the acceleration of the object. Emphasize the x vs t2 relationship and correct use of units, however stating that the slope has the units of acceleration would be premature, because that quantity has yet to be defined. (This type of reasoning should be assigned for gifted students.)
Explain that acceleration isn't always the result of change in speed. Ask students to provide you with examples of motion where they're moving with constant speed or velocity, however their direction of motion changes continuously (a carousel, a bicycle on a circular path, etc.). Although you may have a constant speed, your change in direction means you're accelerating.
Extend the discussion until you arrive to the point where some objects move with a change in both speed and direction at the same time; example roller coaster. The cars reach the top of the incline. Suddenly, they plummet toward the ground and then whip around a curve. You are thrown backward, forward, and sideways as your velocity increases , decreases, and changes in direction. Your acceleration is constantly changing because of changes in the speed and direction of the cars of the roller coaster.
Explain constant acceleration is a steady change in velocity. That is, the velocity of the object changes by the same amount each second. For example an airplane's acceleration may be constant during a portion of the its takeoff.
Explain the meaning of the slope in a velocity vs. time graph is acceleration and from the slope equation.
- When an object speeds up the final velocity is greater than the initial velocity, so acceleration is positive (a>0)
- When an object slows down the final velocity is smaller than initial velocity, so acceleration is negative (a<0)
- When an object moves with a constant velocity then the final velocity and initial velocity are equal, so the object does not accelerate a=0
Explain from the graph v=f(t) above, that the instantaneous acceleration is how fast a velocity is changing at a specific instant. Example; A skateboarder moving along a half-pipe changes speed and direction. As a result, his acceleration changes. At each moment he is accelerating, but his instantaneous acceleration is always changing.
Guided Practice: What activities or exercises will the students complete with teacher guidance?
After the content is presented or at different stages during the presentation of the content (optional) this activities or exercises should be completed by the students under teacher guidance:
- Represent the motion that would result from the following configuration: (See Attachment: Figure for teacher guidance exercise)
a) qualitative graphical representation of x vs. t
b) qualitative graphical representation of v vs. t
c) qualitative graphical representation of a vs. t
d) general mathematical expression of the relationship between x and t
e) general mathematical expression of the relationship between v and t
f) general mathematical expression of the relationship between a and t
- A rubber ball rolls down an incline table, starting from rest. After 5 seconds, its velocity is 10 meter per second. What is the acceleration of the ball?
Problem Solving Skills:
Read and Understand
What information are you given?
time(t) = 5 seconds
starting velocity () = 0 m/s
final velocity ( ) = 10 m/s
Plan and Solve
What unknown are you trying to calculate?
acceleration (a) - ?
What equation contains the given quantities and the unknown?
Replace each variable with its known value.
down the table
Look back and Check
Is your answer reasonable?
In free fall acceleration, objects accelerate at a rate of 9.8 ; if the table is not very steep, a value of 2 seems reasonable.
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the lesson?
At this point of the lesson, students should be able to complete the exercises on the reinforcement hand out. (See attachment, Reinforcement activities and exercises for acceleration)
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
The teacher should conclude the lesson by reinforcing the following ideas:
- Any changes in velocity or changes in direction or changes on both can be described as acceleration.
- When an object's changes in velocity are the same for every time interval, the object is moving with constant acceleration.
- When an object speeds up: if the final velocity is greater then initial velocity, the acceleration is positive (a>0). When an object slows down: the final velocity is smaller than the initial velocity, so acceleration is negative (a<0). When an object moves with constant velocity: the final velocity and initial velocity are equal, so the object does not accelerate a=0
- To calculate acceleration use the equation:
- The meaning of the slope in a speed vs. time graph is the acceleration of the object. It could be positive, negative or zero.
- In a displacement vs. time graph a curved line represents the acceleration. To calculate the instantaneous acceleration on that graph, find the smallest change in velocity at a specific instant.
The teacher will determine if the students have reached the learning targets for this resource by taking traditional multiple-choice, true and false, or fill in the blank assessments. One of these assessments is included in the Attachment section of this lesson. Unit 1 Self Assessment. Bioscopes; by Charles Carpenter. (used with permission)
Also, Unit 1 Activity 3 Falling For Gravity, you will find an excellent lab to monitor student gains through graphical analysis and critical thinking. (Optional Assessment for collecting, organizing and graphing data)
The teacher will gather information both formally and informally about student understanding throughout the lesson. At the beginning of the class the teacher will review previous content (distance, position, displacement, speed, velocity, and graphical analysis) to check their ability to understand acceleration. By asking quick questions about these topics informally we have an idea about what they need to know before moving on to other more difficult topics.
- Demonstrate through rolling an object down an incline, or release it from a certain height. This will catch students attention immediately; during this encourage them to observe, describe, and explain what they see. The teacher will be able to gauge their understanding.
- Reading and Writing:
- Encourage students to read about acceleration in their core textbook, using the web, reading another physics book or through other resources and complete a concept map to organize what they know about acceleration. The teacher will circulate and interact with the students while they do their work, checking their progress through the activity and providing help.
A sample student created concept map: Chart.docx
Feedback to Students
Students will get feedback about their performance or understanding during the lesson in different stages during and after the class time:
- Encourage students to check their ideas with a classmate and the teacher during the observation; through describing and explaining the opening demo.
- Students will be able to assess their own understanding through their use of resources. The text or online resources will provide guidance to prove and support their ideas. The homework assignment will reinforce their learning.
- The teacher will review their work and be able to see if students are on the right track and redirect them if necessary.