February 1, 2019

Happy Friday! Some of us are at a contest today, so check out the following:

Period 3-4, 8-9
Be sure to have what you need for the magnet lab, with the exception of #6. If you have not yet done so, turn in the lab. Also turn in the magnetic domain and earth magnetic field sheets in the pack from early this week.

Check out two videos. One is on the earth's magnetic field. The second is on charged particles moving through magnetic fields. The symbol for a magnetic field strength is B, and the unit for magnetic field strength is a Tesla (1 Tesla is a really strong field...our big magnet is a fraction of a Tesla). Take notes on all this. You will start to use cross products as well as right-hand rules to figure out the direction particles get pushed by magnetic forces. Circular motion results from these cross product forces, so work together to try and figure out a few things.

Be sure to get a page with some practice problems from the book. It uses this notion of circular motion of particles in a magnetic field (or B-field). We are using mv^2/R = qvBsin(theta). In many cases the angle between velocity and the B-field will be 90-degrees, so the sine will often be 1.
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Period 5
If your coaster group has not yet shared the summary paper for your coaster, please do so today. We are into energy, and the BIG idea we've been introducing is conservation of energy - perhaps the single most important concept in science, and a reason why we are alive. Energy can transform from one type into another, such as potential energy (due to height) converting back and forth into kinetic energy as something moves up and down hills on a roller coaster, or flies through the air (slows as it rises, with KE => PE; or speeds up as it falls, with PE => KE).

To see examples of the math behind conservation, check out this Khan Academy video on conservation of energy. This one shows basic PE-KE conversions, similar to what you had with your coaster. Remember conservation means "energy can be neither created nor destroyed, just transformed from one type to another" if there is nothing else adding or taking energy away from you (such as someone pushing or pulling an object, and forcing it to speed up or slow down). Do take notes on the video so you have a numerical example of how to deal with conservation.

From the video, then try to complete the conservation of energy sheet you got on Tuesday. Just remember in all the examples shown, the TOTAL energy stays the same, where Total E = PE + KE. Work together and talk things through based on the video example. If you complete it, turn it in before leaving and we will pick this up next week! Thanks!