Process
BUILDING THE CATAPULT
Materials and Methods:
For this project you will be building catapults. You have the choice of working by yourself and building a compact catapult (dimensions specified below) or working in groups of 2 and building a larger catapult (dimensions specified below).
Solo CatapultYour catapult can be either a small individual sized catapult (see pictures at the Resources page for examples) or it can be a larger catapult resembling that of the team catapults.
For a smaller catapult you will need to be able to launch a marshmallow 3-6 meters. The individual catapult should not exceed 1.5ft x 1.5ft x 1.5ft. Your catapult must be able to launch at two angles at/or between 90 and 180 degrees. All building will be done outside of class time. |
Team CatapultYou will need to create a catapult that does not exceed 3.5 x 3.5 x 4ft. (See pictures at the Resources page for examples) Your catapult will need to be able to launch a tennis ball 10-15 meters at two angles at/or between 90 and 180 degrees.
All building will be done outside of class time. |
Possible material suggestions:
1) Rubber bands 7) 2 x 4 Lumber
2) Masking tape 8) Nails
3) Meter stick 9) Bungee Cords
4) Wood supports 10) Eye hooks
5) Glue
6) Lumber scraps
LAUNCH DAY
For this project you will use a combination of your experimental data with a class-developed model to accurately hit a designated target. On testing day you will have to calculate the theoretical range of a projectile fired from your catapult from both projection angles. You will then have 15 minutes to make adjustments to your catapult and prepare it for launch. A successful launch will be in close proximity to the designated target. Therefore, you must design and test your catapult so that on testing day you can make whatever adjustments are needed. The catapult design MUST be complete on the day of testing. You can not continue to build on testing day.
All catapults should be composed of scrap materials found that you provide I will provide the marshmallows/tennis balls. The appearance and functionality of the catapult will be judged, but you should pay careful attention to design elements that affect the ability of your catapult to adjust to new distances. There are several design ideas provided in the Resources section of this project. You may use one of these designs or adapt one to guide your catapult design.
YOU MUST BE ABLE TO TRANSPORT YOUR OWN CATAPULT. YOU MUST HAVE THE MEANS TO GET IT TO AN FROM SCHOOL.
All catapults should be composed of scrap materials found that you provide I will provide the marshmallows/tennis balls. The appearance and functionality of the catapult will be judged, but you should pay careful attention to design elements that affect the ability of your catapult to adjust to new distances. There are several design ideas provided in the Resources section of this project. You may use one of these designs or adapt one to guide your catapult design.
YOU MUST BE ABLE TO TRANSPORT YOUR OWN CATAPULT. YOU MUST HAVE THE MEANS TO GET IT TO AN FROM SCHOOL.
PRESENTATION
You will be turning in a short report on this catapult project. (See report criteria below) During the competition day, you will have 15 minutes to set up your catapult so that it can fire a marshmallow/tennis ball at the calculated distance.
You will be graded on the following items:
1) Design Plan
2) Data Analysis
3) Conclusion
4) Organization and presentation of report
Your Design Plan Must Include:
1) A list of materials used (should be bulleted)
2) A diagram of your catapult. The diagram should have all dimensions labeled (including units) and should be neatly drawn. Your diagram should be drawn on plain white paper and should fill most of a single page.
Your Data Analysis Must Include: (IMPORTANT)
1) Data table that includes THEORETICAL and EXPERIMENTAL (if possible) time of flight(s), distance flown in horizontal direction (range), angle of launch, impact velocity and height (Ymax). You must test at least 2 different angles using 3 replicate trials for each angle. ALL theoretical calculations must be included in this data analysis section.
2) A value for the average initial velocity of the marshmallow/tennis ball and an explanation of how initial velocity of the projectile was determined. (Refer to your knowledge regarding the determination of velocity and refer back to the horizontal projectile motion laboratory)
3) How did changing the angle affect the characteristics of your trajectory? The initial velocity?
Organization and Presentation:
1) Report should be neatly typed and sections should be well marked.
2) Grammar must be correct.
3) All answers are presented in complete sentences excluding the list of materials which may be bulleted.
Conclusion:
Your conclusion should include an overview of your findings and describe any sources of error that might be present. Give some examples of real life projectiles whose landing spots must be carefully predicted.