(PART 3) Applied STEM: Rocketry and its Components

(Part 3)

V. Methods and Activities
(Describe the methods and activities selected to help students achieve learning goals.)

Accommodations for Differentiation Instruction: Students demonstrating an extended understanding of applied rocketry and scientific inquiry will be encouraged to accelerate with higher levels of scientific, mathematical, and engineering sophistication. Students capable of applying a more creative and scientifically sound approach to this lesson will be encouraged to do so (e.g., independent study.) Students’ ability levels will be closely monitored. In addition, the Team Stanton Rocketry Challenge will be available for interested students, whereby they have to design a rocket, with a payload below the nosecone to house a raw egg and insulation, and parachute made from a thin plastic material. Students will decide on a geometric design, based upon past launch tests and success. Using digital cameras to capture the different angles of each launch will allow students to view every variable of launch (ascent), apogee (highest altitude), payload separation, parachute deployment, and descending payload within a certain parameter.

 (Motivational Strategy Over Several Weeks) View pre-selected snippets from NASA DVDs and videos depicting the beginning of rocketry testing by the U.S. Army and Air Force. Observe, in particular, the successes and failures of NASA’s rocket launches; analyze the footage and decipher possible reasons for any anomalies. Notice the Atlas rocket explosions due to its instability. Discuss how NASA engineers used and continue to use Scientific Inquiry for rocket designs and launches. Students will interject their own observations and hypotheses as to why certain anomalies occurred. Then, the actual reason(s) will be disclosed.
 Discuss the basics of model rocketry (parts of a rocket and their functions, types of propellant – solid / liquid) after distributing the technical manual to all students. Students will read the manual at home for homework with a discussion the following week.
 Introduce solid fuel used for model rocketry (mixture of Nitrate, Carbon, and Sulfur).
 Discuss single and multi-stage rockets and the advantages of each.
 Discuss the printing on engine casings (e.g., C 6-5).
o C = Total Impulse (overall energy measured in Newton-seconds)
o 6 = Average Thrust in Newtons (indicates how long the main propellant will burn; a C 4 would deliver a weaker thrust over a longer period of time; a C 10 would deliver a stronger thrust over a shorter period of time)
o 5 = Time Delay (number of seconds during ‘coasting phase’ before ejection charge is ignited)
 Using engineering rules and paper, students will design their own single stage rocket. Discussion will occur and changes made, if necessary. (Multi-staging for advanced students)
 The instructor will demonstrate how to use X-acto knives safely. (X-acto knife use will occur under the direct observation of the instructor.)
 Students will wrap their pre-selected tube with duct tape. Suggestions will be given, as needed. Students will measure the diameter of their tubes and multiply by Pi (3.14) to calculate the circumference. This will indicate how to measure each piece of duct tape for the tube. Students will round to the nearest ¼.
 The purpose of a rocket’s nose cone will be discussed. Students will use index cards (size depending upon the tube’s circumference) and construct a nose cone. The instructor will check each cone for passable margins-of-error.
 Hot glue nose cones to top of body tube. Look through the bottom opening for alignment (pivot as needed); allow drying. (Students may choose to tape their nose cones, if they wish. However, aerodynamically, it is ill-advised. Those who feel their flights are impeded by the tape may opt to forego taping their next vehicle.)
 Students will design their fins (3 or 4) for their vehicles. The design must be approved by the instructor prior to blueprinting. Corrugated cardboard boxes work best for fins (ask students the reason for this). X-acto knives will be used with cutting boards. (Careful attention will be given by the instructor.)
 Fins will be hot glued to the body tube with alignment ensured using line of sight. Fins will be an equal distance from each other for stability and even air distribution during flight.
 Launch lugs (plastic pencil holders cut at approx. 45 degree angle) will be glued to ensure a stable launch and acceptable trajectory.
 Stability (pp. 7-8 in technical manual) – Have students read this section and discuss possible reasons for an unstable flight. Share examples as to what might cause a rocket to ‘tumble out of control’.
 Review engine casing printing (e.g., D 12-5) using an assessment.
 Using the digital balance, weigh each rocket to determine engine size needed.
 For students clustering, use electrical tape to wrap the engines securely.
 Engine Mounts:
o Refer to pg. 4 in technical manual for basic information.
o Students will use cardboard boxes (corrugated) to construct their engine mounts.
o Measure the diameter of the rocket (through the center, measuring inside only).
o Use the formula to calculate the radius (r = d/2).
o Using a compass and ruler, turn the center wheel to position both ends of the compass the number of inches as the radius.
o Draw two circles on a piece of cardboard (be careful to ensure the circle is perfectly round).
o Place the engine directly in the center of the circles and trace the engine’s circumference inside the circles.
o Use the X-acto knife and carefully cut around the inner circle (engine’s circumference). Then, cut around the outer circle (rocket’s circumference).
o Place the engine(s) inside the inner circle to ensure a fairly tight fit.
o Remove the engine(s), and place the circles inside the opening of the body tube to ensure a fairly right fit. (Hint: It is better for the circular piece of cardboard to be a tad larger, for it can be trimmed using scissors.)
o Hot glue the engine(s) inside the inner circle (instructor will do this with novices. Those who have mastered the skill may glue their own, under the instructor’s direct supervision).
o Hot glue the entire engine mount inside the body tube. (Important: Be sure not to push too hard; the bottom of the engine should be flush with the bottom of the body tube or protrude slightly.)
o Allow engine mounts to thoroughly dry.
 Once the vehicle appears to have passed all aspects of stability and aerodynamics, it is ready to launch.
 Launch Day:
o Needed Materials: Mantis launch pad facility, Hawks Launch Central controller, lawn and garden battery, additional alligator clips and wiring, WD 40, wash cloth, backpack, masking tape, tackle box (housing engines, igniters, plugs, tape, additional items), two stop watches, altitude tracker, hand-held tape recorder, two-way radios, Tangent chart for calculating altitude, calculators, digital video cameras (Check all components to ensure proper working order)
 Rockets will be prepped inside using igniters and engine plugs.
 One student will be designated as the videographer and record the entire process. After viewing the video for evaluation purposes, a DVD of all launches will be given to each student at the end of the unit for home enjoyment.
 After setting up the launch pad outside and testing all electrical components, students will position themselves, in accordance with the instructor’s directives, for purposes of recording different types of data. Two students will walk 300 paces with a two-way radio, altitude tracker, and stop watch (timing lift-off to apogee – highest altitude). Two other students will remain at the launch site with a two-way radio and stop watch (timing total flight from lift-off to touchdown).
 The instructor will stress safety procedures of launching a rocket and give examples.
 Once a student has placed his/her rocket on the launch pad, the launch controller will be connected to the engine via alligator clips. The launch director will conduct an electrical connection test. Once established as “go” for launch, the countdown will begin (e.g., T-minus 5, 4, 3, 2, 1, 0, launch commit – student will press the launch button until vehicle ignites and lifts off), lift-off! Students given specific positions will begin to record their data.
 Once the rocket has launched and touched down, the instructor will give the “okay” for the student to retrieve his/her rocket.
 Data collectors (students) will radio their data to the instructor who will record all data on the hand-held tape recorder along with the student’s name. (This will be used for calculating altitude and rate of speed at a later date.)
 The above steps will be repeated for each student.
 Once all launches have concluded, students will apply formulas to calculate their rockets’ altitudes and rates of speed (pp. 10-11 in technical manual).
 This unit will allow students the excitement of experiencing Scientific Inquiry while applying higher-level math skills. Additionally, students will gain an advanced understanding of rocketry flight to help achieve higher-levels of engineering design and construction (e.g., multi-staging).