Moving at the speed of a Laser
Subject Area:
Physics
Associated Unit:
Speed and Constant Velocity Particle
Lesson Title:
Moving at the Speed of a Laser
Image 1
Image file: .jpg
ADA Description: Photo shows a physics lab
optics table with red lasers shining in a dark room.
Source/Rights: Dr. Li Research Group website
http://faculty.fiu.edu/~hebli/
Grade Level:
11 – 12
Time Required:
2 hours
Summary:
Students are introduced to one dimensional kinematics through the physics concepts of
speed and velocity. This includes a review of position, displacement and frame of
reference. A similarity is made between the displacement of an object and the straightline distance of a laser beam. They are to predict the speed of the battery powered
vehicle and use it to develop a mathematical and graphical relationship between the
position of the vehicle and the time for the motion.
Engineering Connection:
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Many types of engineers carefully observe and analyze systems to determine what
causes them to behave as they do. They examine how systems work and make predictive
models of them. In this lesson, students observe systems and make predictions about
what they see and analyze data collected, just like real engineers do. Doing this serves
as a hands-on application of aspects of the iterative engineering design process.
Engineering Category:
1. Relating science and/or math concept(s) to engineering.
Keywords:
displacement, distance, frame of reference, kinematics, motion, speed, velocity
Educational Standards:
State STEM Standards:
Standard 1: The Practice of Science SC.912.N.1.1, SC.912.N.1.2
Standard 3: The Role of Theories, Laws, Hypothesis, and Models SC.912.N.3.1,
SC.912.N.3.3
ITEEA Standard:
Standard 5: Students will develop an understanding of the effects of technology on the
environment; (9-12) I: With the aid of technology, various aspects of the environment can
be monitored to provide information for decision-making. Standard 13: Students will
develop the abilities to assess the impact of products and systems; (9-12) J: Collect
information and evaluate its quality; K: Synthesize data, analyze trends, and draw
conclusions regarding the effect of technology on the individual, society, and
environment.
NGSS Standard:
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SC.912.N.1.1: Define a problem based on a specific body of knowledge, for example:
biology, chemistry, physics, and earth/space science, and do the following:
1. pose questions about the natural world,
2. conduct systematic observations,
3. examine books and other sources of information to see what is already known,
4. review what is known in light of empirical evidence,
5. plan investigations,
6. use tools to gather, analyze, and interpret data (this includes the use of measurement
in metric and other systems, and also the generation and interpretation of graphical
representations of data, including data tables and graphs),
7. pose answers, explanations, or descriptions of events,
8. generate explanations that explicate or describe natural phenomena (inferences),
9. use appropriate evidence and reasoning to justify these explanations to others,
10. communicate results of scientific investigations, and
11. evaluate the merits of the explanations produced by others.
SC.912.N.1.2: Describe and explain what characterizes science and its methods.
MAFS Standard:
MAFS.K12.MP.1.1: Make sense of problems and persevere in solving them;
MAFS.K12.MP.4.1: Model with mathematics.
LAFS Standard:
LAFS.1112.RST.3.9: Synthesize information from a range of sources (e.g., texts,
experiments, simulations) into a coherent understanding of a process, phenomenon, or
concept, resolving conflicting information when possible.
LAFS.1112.SL.1.1: Initiate and participate effectively in a range of collaborative
discussions (one-on-one, in groups, and teacher-led) with diverse partners on grades 11–
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12 topics, texts, and issues, building on others’ ideas and expressing their own clearly
and persuasively.
Pre-Requisite Knowledge:
Students will need to have a basic understanding of precision, accuracy, dependent and
independent variables and significant figures.
Students should also have an
understanding of recently covered concepts of distance, displacement, graphs and the
use of dimensional analysis.
Learning Objectives:
After this lesson, students should be able to:

Define speed and velocity.

Identify the relationship between position and velocity.

Observe a system and make predictions or analyze about what they see.
Introduction/Motivation:
Motion occurs all around us. We see objects such as cars, people and soccer balls in
move in different directions with different speeds. The study of how objects move is
kinematics. We begin kinematics with the study of one-dimensional motion. In one
dimensional kinematics we will only consider the motion that takes place in one direction.
Only up-down or left-right; or even diagonally; the only direction of interest is up-down,
left-right or diagonally. Consider one dimensional motion as if the object was on a straight
line railroad track. The only motion possible is forward or backward along the direction
of the track.
Motion takes place over time and depends upon the frame of reference. If you were to
stand up and stay still would you say that you have no motion? Well, it depends on your
frame of reference. If you were to consider your body at the atomic level, you have many
cells that are moving. Your nerve cells and your respiratory system is still moving. What
if you were being seen from the perspective of the Moon? Your frame of reference would
be space and you would be rotating around the Earth’s axis and moving around the Sun.
Most of the objects in motion that we will be dealing with will be with respect to the frame
of reference of Earth. Any frame of reference may be chosen as long as it used
consistently to determine changes in position (of an object).
Ask the student who is sitting in the farthest location from the door (Student 1) what would
he/she say is the distance from where they are to the door? Let’s say Student 1
approximates the distance between his/her location and the door to be about 25 feet.
(You could measure this straight distance, from the door to their seat, to verify the
estimate. Ask Student 1 to walk and measure the time it takes from their seat to the door
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as you are moving to Student 1’s seat [with a laser pointer]. Ask Student 1 if this estimate
of 25 feet is the distance travelled or the displacement? What is displacement?
Displacement is the difference in final position and initial position. The distance travelled
is the total distance travelled to get to his/her seat; moving around desks, chairs and/or
columns in the room from beginning position to end position. Displacement is the distance
between where you end up and where you begin. Displacement is similar to the straight
laser beam distance from your seat to the door. Shine the laser pointer to the door, right
next to Student 1. This straight distance between final position and initial position is
displacement. Displacement is a vector; which means that it has direction. Ask Student
1, if there is a fire alarm, does he/she want to go in the displacement direction of their
seat or in the displacement direction of the door? There is a difference in direction.
Student 1 may now return to his/her seat.
Hold a tumble buggy car and have it ready for use.
Teacher Guided Questions
Student Responses
How fast do you walk?
How fast do you run?
What is this in units of?
Who is fastest man in the world?
feet/second, meters/second
Usain Bolt (100 m in 9.58 seconds)
How fast would you run 100 meters?
(If you drive) How fast do you normally drive?
What is the fastest you have driven your car?
A speedometer is in what units?
km/hr and miles/hr
Does a speedometer tell you direction?
No
What is the fastest thing known to man?
Light
What is the speed of light?
299 792 458 meters/second
What is that in miles/hour?
conversion problem
What is the speed of a laser?
It is the same as the speed of light!
Speed is defined as the total distance travelled with respect to time it takes to travel the
distance and velocity is the displacement with respect to time. Velocity is speed in a
specific direction.
A lap around the track is one quarter mile and let’s say you can run that in one minute. If
you finish where you began then your displacement is zero. Your speed of one lap around
the track is one quarter mile per minute but your velocity of on lap around the track (if you
end up where you started having a displacement of zero) is zero.
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Speed is stated as 50 miles per hour (with no regard to direction) and velocity is 50 miles
per hour northbound (on I-95 to Orlando to go to Universal Studios). Question #1 (for
your lab experiment): Approximate the speed of your tumble buggy car?
Tumble Buggy Car Lab
Lesson Background & Concepts for Teachers:
Most people consider speed and velocity to be the same and may even use these terms
interchangeably. While speed and velocity are similar, they are definitely not the same.
Speed is how fast an object is moving regardless of the direction it's going, whereas
velocity is how fast an object gets somewhere with respect to direction. Speed is a
measure of how fast an object moves, while velocity is a measure of how fast an object
gets somewhere.
http://www.physicsclassroom.com/class/1DKin/Lesson-1/Speed-and-Velocity
Vocabulary/Definitions:
Word
Definition
kinematics
The study of things that are in motion.
distance
The length of how far apart objects are.
displacement
Distance between final position and initial position.
frame of reference A framework used for the observation/description of motion.
speed
The rate of change in distance with respect to time.
average speed
Distance travelled by an object divided by the duration of interval.
velocity
The rate of change in displacement with respect to time.
Associated Activities:
Matching the Motion
Position, Velocity and Acceleration
Assessment:
1. Individual/Class Participation.
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2. Each student will submit their lab work performed for the assigned Tumble Buggy Car
Lab.
3. Quiz.
Lesson Extension Activities:
Learn about position versus time graph using the virtual lab PhET Interactive Simulation
from
the
University
of
Colorado
at
Boulder
at
http://phet.colorado.edu/en/simulation/moving-man.
Guest Speaker: Dr. Hebin Li at Florida International University; Dr. Li is currently
conducting several research projects in the Department of Physics including using
femtosecond lasers to study the atoms/molecules of semiconductor nanostructures.
Additional Multimedia Support:
The Physics Classroom
http://www.physicsclassroom.com/class/1DKin/Lesson-1/Speed-and-Velocity
Li Research Group
http://faculty.fiu.edu/~hebli/
The Physics of Lasers
http://www.laserfest.org/resources/lesson-teacher.pdf
Contributors:
Gerson Pereira
Supporting Program:
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RET 2015 Program at Florida International University
Acknowledgements:
The contents of this digital library curriculum were developed as a part of the Research
Experience for Teachers Program at Florida International University’s College of
Engineering and Computing.
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