Grade 6-8 | 10 (45 min) Classes
In this lesson, students will answer the question, how does gravitational potential energy transform to kinetic energy in a model rocket flight? The students will read a story about humans living on Mars in the year 2343 who wish to launch rockets to the moons of Mars. They will anticipate how the gravitational force on Mars will affect their exploration.
Students will hypothesize how the gravitational force on Mars will affect the gravitational potential energy of a model rocket. After a review of potential and kinetic energy, students will practice what they learned and build and test a rubber band rocket. They will then review the data and apply their learnings to build a model rocket in groups to analyze its transformation of energy.
After the flight, the students will combine their data into a class data chart. They will compute how their rockets would be affected if they were being launched from Mars.
The student’s final product will be to complete a Claims- Evidence- Reasoning writing piece supporting their final conclusions. A traditional multiple-choice quiz is included for use if desired.
In 1949, a clandestine group of government scientists met at a secret airbase in Nevada to form Project Star Hopper. The goal was to produce a fast and maneuverable piloted vehicle to compete with the unidentified objects commonly referred to as “flying saucers.” With the nation’s best engineers on the task, plans were drawn up for a sleek and functional atomic-powered vessel that could be launched quickly to intercept the aggressors. The result was the Star Hopper – the world’s first interplanetary spacecraft. A small fleet was constructed and tested, and by 1955, they were ready to protect the skies from alien invaders. Or so we were told…
It was absolutely crucial that the Star Hoppers were able to land accurately on the stars if they were to be successful in identifying the aliens. The engineers at Project Star Hopper need your help to determine how to make the rocket land accurately for the pilots navigating space. The focus of your research will be on the recovery system and adjusting the length of the streamer
Targeted Performance Expectation(s):
Next Generation Science Standards (NGSS)
Develop a model to describe that when the arrangement of objects interacting at a distance changes, different amounts of potential energy are stored in the system.
Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object.
Evaluate competing design solutions based on jointly developed and agreed-upon design criteria using a systematic process to determine how well they meet the criteria and constraints of the problem.
Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
Common Core Standards - English
Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks.
Common Core Standards - Math
Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
Write an inequality of the form x > c or x < c to represent a constraint or condition in a real-world or mathematical problem. Recognize that inequalities of the form x > c or x < c have infinitely many solutions; represent solutions of such inequalities on number line diagrams.
Understand the concept of a ratio and use ratio language to describe a ratio relationship between two quantities.
Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations.
Recognize and represent proportional relationships between quantities.
The peak altitude or highest point of a rocket’s flight.
GRAVITY POTENTIAL ENERGY
Energy that is stored due to the gravitational force of the Earth, dependent on the object’s mass and height, and measured in Joules.
Force that pulls everything down toward the center of the Earth.
Device used to ignite a rocket engine
Unit of work or energy, abbreviated as J
Energy of motion that is dependent on mass and velocity, measured in Joules
Relationship between two variables such that when one variable changes, the second variable changes in the same manner.
Relationship between two variables such that when one variable changes, the second variable changes in the opposite manner.
Potential energy is energy that is stored in an object and is dependent on its position. While there are several different types of potential energy, Gravitational Potential Energy is the focus in this lesson. Gravitational Potential Energy (GPE) is the energy that is stored because of the object’s height. It is a result of the gravitational force of the Earth. GPE is calculated by multiplying the mass of the object by the gravitational force (on Earth, this is 9.8 m/s2) by the height (or distance that the object can fall). It is written:
Thus, a heavy object will have a greater GPE than a lighter object. The higher the object is (in other words, the farther away the object is from the center of Earth), the greater the GPE. The unit of measurement for GPE is the Joule, abbreviated J.
Since GPE depends on gravitational force, an object on a planet other than Earth will have a different GPE. As an example, the gravitational force on Mars is 3.7 m/s2. An object on Mars would have less GPE compared to its GPE on Earth, assuming the same mass and distance from the planets.
In a model rocket, the transformation of energy is related to the momentum of the rocket. The Law of Conservation of Energy states that energy is neither created nor destroyed, it is transformed. In a model rocket, the GPE is transformed into kinetic energy. Kinetic Energy (KE) is the energy of motion. KE is calculated by multiplying two variables – mass and velocity. The equation for KE is as follows:
KE is a scalar quantity. Since it does not have direction, KE is described in magnitude. The unit of measurement for KE, like the unit of measurement for PE, is the Joule, abbreviated J.
Energy in Rocketry
Review the steps of the rocket flight sequence, alongside the energy conversion:
|Step||Flight Sequence||Energy Conversion|
|1||Electrically ignited model rocket engines provide rocket liftoff.||Since there is nothing moving, the rocket’s KE = 0 and the GPE =0 since its height is 0|
|2||Model rocket accelerates and gains altitude.|
|3||Engine burns out and the rocket continues to climb during the coast phase.||The rocket is gaining both speed and height, so GPE and KE are both increasing. Right before it coasts, the KE is the highest|
|4||Rocket reaches peak altitude (apogee). Model rocket ejection charge activates the recovery system.||The rocket has the greatest height therefore the greatest GPE and there is no KE.|
|5||Recovery system is deployed. Parachutes and streamers are the most popular recovery systems used. Rocket returns to Earth.||As the rocket falls, GPE is converted to KE.|
|6||Rocket touchdown!||Right before landing the KE is greater than the GPE|
Using the Estes Altimeter
Altimeter Functions: The altimeter will record the highest point that the rocket reaches. This is called apogee.
- To turn on and use the altimeter,
- Install the battery.
- Using a pen or screwdriver, slide the switch to ON.
- The Altimeter will display 0 feet or meters. (When not in use, always turn it off.)
- With the altimeter on, press and hold the button until the required function is displayed, then release it to provide access to that function.
- To change units from ft to m, press and hold button until UNIT is displayed, and then release the button. Press button until 0000 is displayed and altimeter is ready for flight.
- To clear the altimeter from the previous launch, press and hold the button until 0000 is displayed, then release. This will clear the display, but the altitude will still be stored in memory. Data for up to 10 flights will be saved.
- To view recorded flights, press and hold the button until REC0 is displayed then released. Press and release the button quickly while in the REC0 mode to view each of the 1-10 recorded flights in order of “last flight first”.
- To exit REC0 mode, press and hold the button until the REC0 display starts to flash and release the button. Press the button until 0000 is displayed.
- To clear flight data memory, press and hold the button until the CLER mode is displayed and then released. Press and release once more to clear the memory of all the launch data. (Be sure you have written it down first!)
Installing the Altimeter: Attach the altimeter to the base of the nose cone with the clip. If launching the altimeter inside a rocket body tube, pack recovery wading and the parachute with sufficient room for the altimeter to fit easily.
Each Student Needs:
Student Design Portfolio
Stopwatch (1 per group)
The Class Needs:
You must be logged in to download
You must be logged in to download