Homework - brainstorm a notation for keeping track of how far an object moves AND in which direction it travels, e.g. a man walks 20 meters eastward, then 20 meters northward, then 10 meters westward; can you write this in a way that the sum of these three motions gives you the man's final position?
discuss briefly the history of modeling motion
differentiate between average and instantaneous speeds and define constant speed
determine if a toy car moves with constant speed
create a scatter plot of the motion of a toy car and discuss the significance of its slope
Homework - read to p. 11 in the booklet (Physics: An Introduction); do the 6 math questions on p. 10
define distance, displacement, speed, velocity and acceleration
"read" position, velocity and acceleration graphs and relate them to one another
draw free-body diagrams and calculate the acceleration of various objects
homework - the formal lab is due Friday, Oct 25Saturday, Oct 26 at 11:59 pm on turnitin.com; try to do these problems, after reading the explanations
practice drawing free-body diagrams and using F=ma; model an Atwood machine and a modified Atwood machine
homework - read Unit 2.2 Forces, in your textbook; complete the Forces SL packet
mini-project - Video yourself asking two individuals (not juniors or seniors in high school) what it means to be weightless and record their responses. Then, in 1 min 30 sec or less, clearly explain what it means to be weightless. Also specifically address any misconceptions offered by the interviewees. Don't say too little; show what you know. Plan what you are going to say before you say it! You do not need to appear in the video throughout, but I should see you at least some and hear you for the entire post-interview section. Props, diagrams and photos can be used, if desired. Upload this video to the linked Google folder by the deadline, 11/6.
analyze a block sliding down a ramp (and hanging signs (in translational equilibrium)?)
discuss Newton's 3rd Law
homework - if you haven't already, read Unit 2.2 Forces; you can find a bunch of review videoshere
test over forces (even if you were absent last class)
the mini-projectis due here by class time today; upload it, don't share it; it will count as a major grade
define kinetic and potential energy and work
homework - read pp. 62-69 in your textbook
derive and use the Work-Kinetic Energy Theorem
calculate change in kinetic energy from a force-vs-position graph (key)
I will be providing feedback on your IA through turnitin. The final IA, including the Evaluation, with corrections made based on my feedback, will be due, through turnitin, on Sunday, March 29March 31st at 11:59 PM. This will be a major grade.
* You should have received an email from me on 3/25 with our plans for this week and next. Your primary goal for now is to complete the IA. Make sure you read the email.
Allow me to set the stage by bringing your attention to electrically-charged particles, like electrons, protons, and larger ions. You certainly have heard that objects have either negative or positive charge, or they are neutral. Furthermore, opposite charges attract, while like charges repel. Our focus this week will be on calculating the force of attraction or repulsion.
Please read pp. 169-175 in your textbook.
Then read this document and complete the problems at the end of it.
Take a photo of your work and submit it through turnitin.
If you were interested in learning the detailed ins and outs of all electric (and magnetic) phenomena, you'd want to spend more time thinking about electric (and magnetic) fields, and you'd practice drawing and calculating the fields, and using mathematical expressions for the fields to answer questions about what will happen to charged particles placed within those fields. This is not our goal. I want you to simply understand that electric fields -- electric force fields -- exist around all charged objects, and other charged objects are affected by them. They are a mechanism by which charged particles interact.
We're going to direct our focus to electric circuits, now. Electric circuits are established paths through which electrons flow; the electrons carry energy with them, and they give this energy to whatever they encounter as they move through the circuit, such as a motor or a light bulb. The electrons get the energy, essentially, from a battery, at least for battery-powered circuits. You can think of electrons as energy carriers, carrying energy from a battery to a light bulb, for example. Upon giving energy to a bulb, they circle back through the battery, gain more energy, and then make the trip again.
For electrons to flow in an electric circuit, they must be continuously pushed and pulled forward. This is like a lawnmower, which must be continuously pushed (or pulled) forward to keep moving. The reason it doesn't keep moving forward after the initial push is NOT because things must be pushed to move but because of friction. Friction brings the mower to a rest, so you have to keep pushing it, overcoming more friction. If there was no friction, you could stop pushing and it would coast forward indefinitely due to its ... inertia. Similarly, the electrons encounter friction, which is usually called "resistance" in this context, so they must be continuously pushed forwards. And it is our friend the electric field that does the pushing. And where does the electric field come from? Essentially, the battery. Which is why when the battery is removed from a circuit, the electrons stop flowing.
So, let's shift our focus away from the electric field and just focus on describing the key features of an electric circuit.
Begin by reading pages 6-23 in this booklet that I created. Please read carefully, and critically, and take notes.
Submit the answers to the PhET investigation through turnitin.
*In the simulation, you have the option, under "Show Current", to select "Electrons" or "Conventional". Just leave it as "Electrons". But you might be asking yourself what this means. It's kind of interesting, and kind of irritating, and definitely a quirk of history. Basically, people knew about electricity before they knew about electrons, and they assumed that electricity was the flow of tiny positively charged particles. They wrote it up that way in textbooks. Later, people discovered that the particles were actually negatively charged electrons, and they were flowing in the exact opposite direction to that assumed. This was interesting. Apparently, when creating a model to understand how a circuit works, it does NOT matter which way you assume the charged particles flow. Clockwise flow of positive particles is functionally the same as counterclockwise flow of negative particles. Both assumptions make correct predictions. And today, people continue to use both models, even though one is technically not correct -- the particles really are negative, not positive.
Week of April 27-May 1
Assigned Monday, due Wednesday.
This week, we continue to analyze electrical circuits, making use of a famous equation called Ohm's Law. The goal is to understand the relationships between the resistances of a handful of resistors in a circuit, the voltages across those resistors, and the currents flowing through them.
The assignment that you will be completing is the same one that PreAP physics is completing, as they are currently covering the same material.
Make a copy of the document linked above, fill it out as appropriate, then submit it through turnitin.
This week, we investigate magnetism and the magnetic field. A particular focus is on a type of magnet called an electromagnet.
Begin by watching a recorded lecture on magnetism. My lecture covers some of the material later referenced in the assignment, but not all of it. But this is fine, because you are meant to learn the additional information using the simulations and video clips linked in the assignment.
Then complete this assignment. Make a copy of the document, answer the questions, then submit it through turnitin.
Week of May 11-15
Assigned Monday, due Wednesday.
Electromagnetic induction is an important concept and is part of the story for how we produce electricity to power our cities. Please watch this short video on the topic.
If you are really interested in understanding how we, as a society, generate electricity and get it to people's homes, you might enjoy reading this bookletthat I put together. But given that this is the last lesson of the course, I don't want to require you to read this lengthy explanation. Instead...
I think it could be interesting, if perhaps a little confusing, to learn about the most famous equation in physics: E=mc2. And so I invite you to watch this video from PBS Space Time. You might need to pause the video here and there, or watch it twice, because the guy talks fast. Actually, first, watch this short clip of Einstein himself talking about his equation.
Please answer a few question through this Google form, as one final assignment.
And let's end things with two inspirational videos, both featuring the renowned physicist Richard Feynman: here and here.
Science does not answer all of the questions we humans have, but it is the best method known for answering certain types of questions. The scientific method is an invention; it is important to realize this. It is one of the greatest inventions our species has developed and one of the greatest gifts handed down from previous generations. I hope, throughout your life, you will continue to appreciate this gift. I hope you will always remain curious about the world. I also hope, as scientists do, you will take pride in uncertainty. It is okay to be uncertain. Science is not about proof. No scientific theory is proven. Rather, scientists hold varying levels of uncertainty in their beliefs about different theories. That's how science works, and how progress is made. I think certainty is one of the most dangerous of feelings. It's been a great, albeit strange, year. Take care, please, and have a wonderful summer.