Presentation on theme: "Basic Instructions For the Mousetrap Car Competition"— Presentation transcript:
1 Basic Instructions For the Mousetrap Car Competition Team entry: 2 students requiredDesignMousetrap car construction and runCommunicationTechnical report writingDesign drawings
2 Mousetrap Event Final Scoring Total of the following scoresMousetrap car performance (50 pts max)Design drawing (25 pts max)Technical report (25 pts max)Total Max – 100 pts
3 Design drawing Title card (4” X 6”) Team nameTeam members namesPaper size (18” X 24”), 1” margins,16” X 22” actual drawingMust show scale and units (use 1:1 and inches if possible)Label all partsThree views (front, side and rear)DimensionsAccuracyNeatness (pencil and fully erase)
5 Technical Report Writing Describe the design, construction and operationComputer printed, 12 pt. Type, double-spacedWhite, 8-1/2” X 11” paper, 1” marginsMaximum of 3 pagesGraded onOutlineOrganizationPrecisionSentence formationMechanics
6 Technical Report Organization Cover page (required to contain)TitleNamesAbstract (1/2 page summary)Table of contents (1 page)IntroductionDesignConstruction procedureOperation of the mousetrap carConclusions / RecommendationsAcknowledgementsAppendix (sketches, tables, charts etc.)3 page maximum
7 Mousetrap Race Scoring 2Weight of Mousetrap_________________Weight of CarDistance_______LengthGoal: Minimize weightMinimize lengthMaximize distance
8 Basic Instructions For Building A Mousetrap Car This is a set of basic instructions and tips on how to get started building a mousetrap car.Many other materials and designs are possibleAdapt the instructions to your needs and imagination.
9 MaterialsMousetrapChassis: wood scraps, balsa wood, ice cream sticks, stiff wireAxles: wooden dowels, metal tubes (copper or brass), axles from old toys, ink pens, pencilsWheels: Metal lids, CDs, wheels from old toys, other disk-shaped objectsPull Cord: String, rubber bands or fishing line
10 Physics Concepts Friction Friction is the resistance of motion between two objects. Most friction between the materials in your car reduce the amount of energy that is used to move the car, so it would make sense that you want to reduce that friction. However, you actually rely on the friction between your wheels and the floor to help your car move.Another, less thought of, friction involved in the performance of your car is air resistance. Remember, air resistance acts against the motion of the car and therefore should be reduced to increase performance.
11 Physics Concepts Newton’s Laws Newton’s first law is also known as the law of inertia. Inertia is an object’s tendency to resist change. The more massive an object is, the larger its inertia, and therefore the harder it is to change its motion. Newton’s second law is most commonly known in its equation form, F=ma. Both of these laws should show you that the more massive your car, the more force that will be required to move the car. Remember that, depending on the goal of the car, you may want the car to have some inertia so it will keep moving after the mouse trap has used all it energy. Keep these laws in mind while constructing your car.
12 Physics Concepts Rotational Inertia Just like linear inertia deals with an object’s tendency to resist change of its linear motion, rotational inertia is an object’s tendency to change its rotational motion. The rotational inertia of an object depends on its mass and the distribution of that mass. Since the wheels of your car are the parts that are rotating, you may want to decrease or increase their rotational inertia.
13 Physics Concepts Energy Energy can be defined as the ability to do work. Work is the applying a force to an object, and actually moving that object. If the object is not moved, no work is done. The goal of the project relies on efficiently transferring the spring’s energy to the car’s wheels. The concepts involved in the transfer of this energy rely on an understanding of simple machines. The trap acts as a lever to transfer the energy to the axle. The axle acts on the wheel as a second transfer of the energy. Finally, the energy is used to push the wheel against the floor, causing the car to move. Any friction or resistance in the transfer of energy, leads to a decrease in the efficiency of the machine and decreased performance. Keep the use of simple machines in mind as you design the car, the correct use of these machines will increase your performance.
14 TipsWheels: Old CDs make great wheels, but have very little traction. Stretch a wide rubber band around each wheel; the rubber band can even be glued into place.Pull Cord: Your pull cord needs to be strong enough to withstand the forces exerted by the mousetrap spring. Fishing line, rubber bands (not legal in some competitions) or strong string work well. Winding the pull cord in the wrong direction makes the car go backwards; painting a small arrow on the axle as a reminder can help.Alignment: A mousetrap car that always steers to one side will not be good for competition. Place shims (small pieces of scrap wood) in between the bushings or bearings of one or more of the wheels to align the wheels. It is very easy to do this with balsa wood.Aerodynamics:Keep the number of flat surfaces facing the front of the car down to a minimum. Sanding the body of the car smooth also helps cut down drag.
15 Hints for Better Performance Reduce frictionUse lightweight materialsAmount of rotational inertia depends on the goal of the car.Test the lever arm length and wheel size to determine the best for your type of car.Experiment early and often
16 Possible Websites to check out for ideas Possible Websites to check out for ideas. There are hundreds of sites on the Internet. Do your own research and use some of these if you need additional help.188.8.131.52.184.108.40.206.9.10.
17 Remember Your final score is the total of the following scores: Score on technical reportScore on car design drawingMousetrap car race scoreDon’t focus on the car race and forget the others!