Presentation on theme: "MESA Day 2013 Mousetrap Car 6th-8th Grade - Distance"— Presentation transcript:
1 MESA Day 2013 Mousetrap Car 6th-8th Grade - Distance 9th-12th Grade - Accuracy
2 Objective & MaterialsStudents will build a vehicle solely powered by a standard mousetrap to travel the longest distance on a specified track (MS) or stop the closest to a specified target (HS).Materials:1 standard mousetrapAll other materials are legalNO KITS!
3 First Things First: READ RULES AT LEAST TWICE!! Mousetrap is ONLY source of energyDon’t tamper with mousetrap:No paintNo decorationAlteration allowed ONLY for attaching mousetrap to chassisSpring may not be altered
4 Let’s review physics! Energy: It’s what moves the car. Potential: energy stored in a system (mousetrap spring)Elastic & GravitationalKinetic: energy of motionPotential KineticInertia: The resistance an object has to changing its state of motion.Rotational Inertia: The resistance an object has to changing its state of rotation.Friction: A force that opposes the direction of motion.Static: caused from two surfaces pressing together.Fluid: caused from liquids or gases. In air, this is known as drag.Torque: The force required to rotate an object.Power: The rate at which energy is released or transformed in a system.
5 The Engine: Spring + Lever Arm Energy from spring is transferred to car via the lever armLever arm provides torque required to turn axlesLength of lever arm affects power outputShorter arm = faster outputLonger arm = slower output
6 Wheels & Axles # of wheels : 3 or 4 Wheel radius Wheel grip (traction) The greater the radius, the greater the torque required to rotate the axleWheel grip (traction)Power output must match wheel grip to avoid spinningAvoid wasting energyRatio of wheel-to-axleLarger ratio good for distance, but not necessarily for accuracyFrictionReduce friction between wheels and surfaceAlso between axle and chassisAlignment
8 The Chassis The body of the car Balsawood, plastic, other lightweight materialsMassThe heavier the car, the greater the friction force with the surfaceMore force required to actually move the carLong chassis vs. Short chassisNarrow vs WideAerodynamics (negligible)
9 Fast vs SlowFast:Build a car that will accelerate quickly and “coast” as far as possibleshorter lever armsmaller wheel radiusquick power outputSlow:Build a car that will accelerate slowly over the entire distance that it travels. Less “coasting”.longer lever armlarger wheel radiusslow power outputAccuracy:Can be fast or slowLength of lever armWheel and axle sizeBraking mechanism?quick power output
10 Tips for avoiding DQ’s: Research, research, research!Experimentation is the keySet a working timelineREAD THE RULES….twice….again!!HAVE FUN!!!: It’s not the end of the world.
11 Remind Students: Research, research, research! Experimentation is the keySet a working timelineREAD THE RULES….twice….again!!HAVE FUN!!!: It’s not the end of the world.