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When the car runs over another piece of tape or some other obstacle in its path, this releases the bar on another set of wheels and propels the car forward. Attach one axle to each mousetrap, making sure that it runs between the trap’s body and its metal bar. They must be in the right position so that your car will run correctly. Next, you need to attach four or more mousetraps to the base. You can use glue or another adhesive to hold them in place better. Make sure that there is about half an inch of space between them so that they don’t get caught together.
Step 5: Preparing the Wheels
It’s bad when it causes the axles of the car to stick and not rotated. However, it’s a good thing when it causes the back tires to stick to the ground, giving you more traction and helping propel your car forward. Using large rear wheels allow one rotation of the axle to take the car a much further distance. In other words, a given length of the string from the mousetrap moves the car a greater distance. Carefully wind the string around the dowel by turning the drive wheels. As much as possible, try to wrap just one layer of string around the dowel (picture 1).
Attachments
The concept of torque is also important in flight like in this quadcopter, check out my article Basic Quadcopters. For my experiment I measured the force in grams at 4 centimeters from the axis at 25, 90, and 180 degrees. I then measured at 28 centimeters from the axis and then calculated what the force should be based on the measurements at 4 centimeters. Measurements were also taken at 28 centimeters so a comparison could be done between the calculated and the measured. Torque has been defined either as a twisting force or the tendency to rotate around an axis. A common example of torque is tightening a bolt with a wrench.
Step 6: Prepare the Mousetrap Mechanism // Dowel
This is where the string will be attached to the drive wheels. If the cable tie is slipping, then apply a small dot of glue onto it. Large Wheels – using really large diameter drive wheels gives even larger mechanical advantage for greater distance. Wheel – mousetrap car rolls on wheels this is the geometric shape of a circle.
Mousetrap Cars
Overall this is a really fun and exciting day for the students to see how their designs performed compared to the other teams. First we will begin by cutting our axles from either metal rod or dowel. We will be cutting the axle to 3 and 3/4". We will need two axles. I have had the best luck with positioning the wheels in a vertical way, as well as putting the body of the car in a perpendicular position relative to the bed. When everything has been tested, you can add some detail to your car if you want to.
Step 6: Extend the Mousetrap Arm
Bearing – this is the contact point between the turning axle and the attachment to the chassis; the less friction in the bearings the more efficient the mousetrap car. With too much friction in the bearings the mousetrap the mousetrap might not even move or stop repeatedly. The ideal size for a drive wheel on a speed-trap racer is between 2 and 3 inches but no more than 4 inches. Cut holes a little bit smaller than the dowel through the center of each wheel, then attach the wheels to the chassis. Put the large wheels on the back of the car, opposite the snapper arm.
The last note is to place your mousetrap as close to the front of the car as possible. In non-technical terms, this means that the same force from the mousetrap on each snap gets exerted over a longer string pull. When you have more string, it means more rotations of the axles, and thus your car will go further. If you're planning on teaching this project to a group of kids, then download the attached lesson plan and project sheet. Like all of my lesson plans, it contains the project goal, prep, troubleshooting, and a suggested lesson plan. The lesson plan is an outline, and it's provided as an editable .docx file, designed to be elaborated upon to suite your audience.
VIDEO: May Howard Elementary School students celebrate Engineering Week - Savannah Morning News
VIDEO: May Howard Elementary School students celebrate Engineering Week.
Posted: Sun, 24 Feb 2013 08:00:00 GMT [source]
Step 2: Attach the mousetraps
This lesson plan also includes all the details on the math and science behind the car. The example mousetrap car built in this Instructable is a good place to start, but it's not the absolute best design. We can use our understanding of the math and science behind the car to test some ways to optimize its performance.
How to Build a Mousetrap Car for Distance with Professor Davis
Once it is dry we will drill an 1/8 inch hole at the end of the dowel to attach a string. When the string is enough through the pen, tie something to the other end. Pull it back through and ensure that the object or knot stops against the other side of hole. Let’s break down some things that we changed when we made our new design and finally got a car that would run in a straight line over 6 meters.
Additionally, mousetraps are simpler to use than other potential mechanisms such as wind-up motors or rubber bands. Now it’s time to watch your brand new mousetrap car and show off your creation! You can race against another one of your friends’ cars or test out how fast it will go on a long track by itself. Just make sure that you don’t let anyone touch it while it’s running, or they may get hurt.
After building a couple of Doc Fizzix’s mousetrap car kits I designed several of my own cars although it was basically two different major designs and then small variations. The latest mousetrap car uses a foam block for a chassis, coat hanger wire for axles, and CD wheels. This design works well but it was designed mainly to be inexpensive.
The more the rotational inertia an object has the more torque that will be required to change the objects state of rotation. A large amount of rotational inertia can have an advantage once an object is rotating because it will be harder to stop rotating. For an object that is not rotating we commonly talk about its inertia or its mass; the more mass an object has the more resistance the object will have to any change in it's state of motion. The greater the distance between the average mass of a rotating object and it's point of rotation the greater the rotational inertia of the object. A large amount of rotational inertia can have an advantage once an object is rotating because it will be harder to change it's state of rotating. Not really as big of an issue with slow moving long-distance mousetrap cars air resistance is still a topic that needs to be discussed.
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