mesa day 2013 mousetrap car

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MESA Day 2013 Mousetrap Car. 6 th -8 th Grade - Distance. 9 th -12 th Grade - Accuracy. Objective & Materials. Students 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). - PowerPoint PPT Presentation

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MESA Day 2013Mousetrap Car

6th-8th Grade - Distance 9th-12th Grade - Accuracy

Objective & Materials Students 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 mousetrap All other materials are legal

NO KITS!

READ RULES AT LEAST TWICE!! Mousetrap is ONLY source of

energy Don’t tamper with mousetrap:

No paint No decoration Alteration allowed ONLY for attaching

mousetrap to chassis Spring may not be altered

READ RULES AT LEAST TWICE!!

FIRST THINGS FIRST:

Let’s review physics! Energy: It’s what moves the car.

Potential: energy stored in a system (mousetrap spring) Elastic & Gravitational

Kinetic: energy of motion Potential Kinetic

Inertia: 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.

The Engine: Spring + Lever Arm

Energy from spring is transferred to car via the lever arm

Lever arm provides torque required to turn axles

Length of lever arm affects power output

Shorter arm = faster outputLonger arm = slower output

Wheels & Axles # of wheels : 3 or 4 Wheel radius

The greater the radius, the greater the torque required to rotate the axle

Wheel grip (traction) Power output must match wheel grip to avoid

spinning Avoid wasting energy

Ratio of wheel-to-axle Larger ratio good for distance, but not necessarily for

accuracy Friction

Reduce friction between wheels and surface Also between axle and chassis

Alignment

Wheels & Axles

The Chassis The body of the car Balsawood, plastic, other lightweight materials Mass

The heavier the car, the greater the friction force with the surface

More force required to actually move the car Long chassis vs. Short chassis Narrow vs Wide Aerodynamics (negligible)

Fast vs Slow

Accuracy: Can be fast or

slow Length of lever

arm Wheel and axle

size Braking

mechanism? quick power

output

Slow: Build a car that will

accelerate slowly over the entire distance that it travels. Less “coasting”.

longer lever arm larger wheel radius slow power output

Fast: Build a car that will

accelerate quickly and “coast” as far as possible

shorter lever arm smaller wheel radius quick power output

Tips for avoiding DQ’s: Research, research, research! Experimentation is the key Set a working timeline READ THE RULES….twice….again!! HAVE FUN!!!: It’s not the end of the

world.

Remind Students: Research, research, research! Experimentation is the key Set a working timeline READ THE RULES….twice….again!! HAVE FUN!!!: It’s not the end of the

world.

Let’s Build…

Marvin MaldonadoDirector, SDSU MESAmmaldonado@projects.sdsu.edu

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