Rotational Energy Lab

thingiverse

I created this to investigate rotational energy and moment of inertia. I basically just took a slightly modified version of my CD Acceleration lab and added Nuts and Bolts to the sides of it. This allows me to use fender washers as adjustable weights. The washers can be positioned at different distances from the center of rotation to change the moment of inertia or additional washers can be added to vary the mass. There are many investigations that students could carry out using this device. Print Settings Printer Brand: MakerBot Printer: MakerBot Replicator Rafts: No Supports: No Notes: For the main part and the nuts I printed with two perimeters and 10% infill. If you print the bolts with these settings there is a very good chance you will break them. I printed the bolts with 3 perimeters and 50% infill. Really, they probably ended up being nearly 100%. Post-Printing You'll need some fender washers for weights. Put an equal number on each bolt. Using a nut or two will allow you to hold them in place at different distances from the center of the circle. The "track" is a pair of steel electrical conduit pipes held by bricks and angled to make a ramp. If the angle is too steep the device will slide rather than roll. You can mitigate this by applying a coat of plastic-dip to the cones. How I Designed This I assembled this in Tinkercad by combining my CD Acceleration Lab with parts created using Mike Linus' Nut Job. I had to tweak my CD Acceleration apparatus a little so that the bolts would be centered on the assembled device. Standards NGSS Overview and Background This activity is intended to be done after students have had some experience with conservation of energy and with rotation. Students will learn how they can experimentally determine the Moment of Inertia. This is intended as one of the final activities during the unit on rotational motion. Objectives Students will be able to determine the rotational energy of an object by applying conservation of energy Students will be able to determine the Moment of Inertia for a non-standard object Audiences High school physics students College physics students Subjects Rotational Dynamics Conservation of energy Skills/Standards NGSS Scientific and Engineering Practices Planning and carrying out investigations Developing and using models Analyzing and interpreting data Using mathematical and computational thinking NGSS Crosscutting Concepts Scale, proportion, and quantity Energy and Matter NGSS Core Ideas: PS2.A: Forces and Motion PS3.A: Definitions of Energy PS3.B: Conservation of Energy and Energy Transfer Lesson Plan and Activity Show the rotational motion apparatus rolling down the rails. The rails are electrical conduit held by bricks with homes in them. One end is elevated. You could alternatively use a pair of dynamics tracks laid on their sides. Ask students to determine the Moment of Inertia of the object. No more than 20 minutes should be allowed. That is it. You should give no more instructions to your students. Students should devise their own methodology for accomplishing this task. That said, you should circulate and monitor students as they progress. Asking questions to draw their attention to similarities between this and previous labs as needed. When done students put their work on large whiteboards to share in whole class discussion. They should also photograph their whiteboard with their phone and email it to the teacher before the discussion. Duration This should only take a single class period Materials Needed You will need the following for each group of three students: Pair of bricks with holes Pair of electrical conduit Rotational energy apparatus Pair of fender washers Hudl Technique app on cell phone It is assumed students have use the Hudl Technique App in previous labs. You should also have meter sticks available