Impulse: An Investigation of Impulse/Change in Momentum
Author: Jesse Groff
Source: This material is based upon work supported by the National Science Foundation under Grant No. EEC-1161732.
This Lesson is based upon the Impulse/ Change in Momentum Theorem. This inquiry lesson will allow students to explore the Impulse/ Change in Momentum Theorem using a force plate sensor and energy dampening materials to distribute the force of a falling mass over time. An acrylic cylindrical tube will be utilized as a container for each chosen material. A mass that fits the tube well will be dropped from a particular height. The force plate will register the force peak from the drop and the change in time in which this force was imparted. Students will be able to quantify Force and Change in time data as the materials are changed in order to record them in a data table for analysis. Each material will be given a specific cost. This is to ensure that students remember that in engineering ideas are meant to be scaled up and cost effective so they do not go overboard out of the gate. Through this Inquiry, students will learn the necessary content as well as working “like and engineer”.
What should students know as a result of this lesson?
- Students will be able to measure force peaks and change in time using electronic sensors and software.
- Students will be able to calculate Impulse using force peaks and change in time measurements.
- Students will be able to organize data through creation of their own data tables.
- Students will be able to create a graph that represents their data properly.
- Students will be able to determine the independent and dependent variable/s within their experimental design.
- Students will be able to work successfully as a team in order to reach all goals set.
What should the students be able to do as a result of this lesson?
- Vernier Force Plate Sensors
- Vernier Logger Pro Software
- 2 3/4" Outside Diameter x 2 1/2" Inner Diameter Clear Extruded Plexiglass Acrylic Tube x 6ft long
- Water Beads or Water Pearls
- Polystyrene Foam Beads
- Corn Starch
- Polyurethane egg crate foam
To engage students we will do an exercise called force plate jumping. A force plate is placed on the ground and students are asked to jump from a chair to the force plate sensor. The first jump they are to keep their legs straight, and the second they are asked to bend their knees when they land. This video will help to explain the procedure in greater detail. Only the instructor should watch this video.
After the demo the instructor can pose questions.
Some examples are:
- Why did the Force decrease from the stiff trial to the bent trial?
- What did this mean for the time of impact?
- Is the impulse the same between both trials, should it be the same?
Drop It Like It's Hot Lab
In this lab students will use various materials to develop an efficient plan for decreasing or dampening the impact force of a falling mass by increasing its impact time. Each material used for dampening will have different costs so students control their “spending”. The only change that will occur is the material used or the amount of the material used. In the real world materials are used to accomplish this task on a regular basis. Whether it is cushions on a couch or an air bag in a car, many real world examples can be brought to light in order to add relevance to the lab. For further lab details, please read the lab document below.
Analysis questions will be at the end of the lab addressing the Impulse Momentum Theorem.
In this section groups will present their findings to the class. They will present their findings in a power point like presentation discussing their data and results. Here they will explain their procedure, results, and their conclusion. A simple rubric will be used to asses the students. The rubric will be attached to the lab.
This section will provide a good transition to move into the next section within the unit (collisions). Comparing inelastic to elastic collisions which is a key standard to be addressed.
A quiz will be used to evaluate the students mastery of the Impulse Momentum Theorem. (Analysis Questions and Presentation)
Students must know the following in order to actively participate in this lesson:
- An understanding of free fall.
- An understanding of the scientific method as it pertains to engineering.
- What the word dampening means.
- How to operate Vernier’s Logger Pro software.
- An understanding on how to define/calculate Impulse and Change in Momentum.
Best Teaching Practices
- Inquiry Activities
- Conceptual Understanding of Problem Solving
- Real Life Situations and Problem Solving
- The 5-E Learning Cycle
- Hands On/Minds On Learning
Alignment with Standards
- I. Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly. (HS-PS2-5)
- II. Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution. (HS-PS2-1)
- III. Use mathematical representations of phenomena to describe explanations. (HS-PS2-2), (HS-PS2-4)
- IV. Apply scientific ideas to solve a design problem, taking into account possible unanticipated effects. (HS-PS2-3)
- V. Communicate scientific and technical information (e.g. about the process of development and the design and performance of a proposed process or system) in multiple formats (including orally, graphically, textually, and mathematically). (HS-PS2-6)
- **Standards used from: http://www.nextgenscience.org/hsps2-motion-stability-forces-interactions
Common Core Standards:
- RST.11-12.3. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.
- RST.11-12.7. Integrate and evaluate multiple sources of information presented in diverse formats and media in order to address a question or solve a problem.
- RST.11-12.9. Synthesize information from a range of sources into a coherent understanding of a process, phenomenon, or concept, resolving conflicting information when possible.
- WHST.11-12.2. Write informative/explanatory texts, including the narration of historical events, scientific procedures/experiments, or technical processes.
- I. Science Inquiry and Application - During the years of grades 9 through 12, all students must use the following scientific processes with appropriate laboratory safety techniques to construct their knowledge and understanding in all science content areas: Identify questions and concepts that guide scientific investigations; Design and conduct scientific investigations; Use technology and mathematics to improve investigations and communications; Formulate and revise explanations and models using logic and evidence (critical thinking); Recognize and analyze explanations and models; and Communicate and support a scientific argument.
- II. Forces, Momentum, and Motion - G. Momentum, impulse and conservation of momentum
- **Standards used from: http://education.ohio.gov/Topics/Academic-Content-Standards/Science
- Writing Standards for Literacy: Grades 11-12 - 1:a-e; 2: a-e; 4
Problem Solving using the scientific method
Momentum and the Impulse Momentum Theorem
Data collection and data presentation
Gravitational Field forces
Safety Equipment Needed:
- Safety glasses/goggles
- Nitrile Gloves
Safety Procedures Reminder:
- Closed toed shoes
- Hair pulled back
- Proper clothing or lab coat
This content is applied to the real world by relating the lesson to testing materials for engineering purposes. Engineering seeks to find uses for inventions and innovations that can make life be easier and have better quality. Materials must be tested and scrutinized before consumers can have a chance to buy and use the new technology. This testing is a skill that must be learned and developed and this lesson gives a window into that process. Students who go on into the engineering field need to be able to do this process of testing and analyzing in order to meet a certain goal. In this case specifically, the reduction of impact is used in many fields especially when it pertains to safety.
Analysis questions from the "Drop It Like It's Hot Lab".
Grouping Suggestions: I have about 25-30 students. I am grouping my students in groups of 5. I think that five is a good number for this lab because materials are costly and there is going to be a high number of samples. In order for this lesson to go smoothly I think larger groups are better than groups of two or three unless you are working in a system that has small class sizes, then groups of two or three would be ideal. It basically comes down to amount of samples and cost for materials.
Pacing/Suggested Time: My classes are 47minutes in length. I will spread this lesson out over four days.
- DAY 1: Quick lecture with and demo to build pre-requisite knowledge, hand out and discuss lab Engagement.
- DAY 2: Perform Lab Exploration
- DAY 3: Continue Lab Exploration
- DAY 4: Finish Lab and work on presentation. Exploration
- DAY 5: Present Findings Elaborate/Evaluate
Printable PDF Worksheets
Drop It Like It's Hot Lab