﻿ Physics 100 -- 21-22

Class 68: Tuesday, 5/3/22

Warm Up:   According to Newton's 3rd Law, every force has an equal and opposite force.  So how do you win a game of tug-of-war?

Today:

Homework:

Class 67: Friday, 4/29/22

Warm Up:   What's the best way to get a slow motion video onto a school computer?

Today:

• Check Homework
• Spool Car Project:
1. Assemble spool cars and practice.  The goal is maximum average acceleration.  This entire project is due at the end of next class, so you should try to get your video into your Google Drive by the end of class today.
2. Use a slow motion video, and the Vernier Video Analysis App, to measure top speed, time to reach top speed, and overall time from start to finish.  In Google Classroom, turn in your video to provide proof of your data.  The winning car(s) will have their data verified.
1. Your car's starting point and time
2. The point at which your car entered its fastest floor tile
3. The point at which your car exited its fastest floor tile.
4. The point at which your car stopped
3. Then measure your car's mass.
4. After you have those four bits of data, complete the spool car analysis (pdf).  This will be a project grade, and it will be graded on correctness, not completion.

Homework:

• None

Class 66: Wednesday, 4/27/22

Warm Up:   The 50kg rower has an acceleration of -1m/s2.  She is pulling against the oars with a force of 100N. Draw and calculate all of the forces acting on the rower.

Today:

• Check Homework
• Solve this spool car practice problem. Video help
• Assemble spool cars and practice.  Measure top speed, time to reach top speed, and overall time from start to finish.  Then measure your car's mass.  I suggest using slow motion and the "Coach My Video (CMV Free) App" or the Vernier Video Analysis App.  After you have those four bits of data, find the force of your spool car's motor and the force of friction that is acting on your car.  Show your work.

Homework:

Class 65: Monday, 4/25/22

Warm Up:   A child and a sled together weigh 200N.  The sled is initially motionless.  A parent pulls the sled to our right, across a flat, icy field, for 3 seconds, applying a constant force.  At the moment the parent stops pulling, the sled has a velocity of +6m/s.  After the parent stops pulling, the sled keeps sliding for another 12 seconds and then comes to rest.  We can assume that the force of friction on the sled is the same whether the parent is pulling or not.

How much force is the parent applying to the sled in this problem?

Today:

• Review some problems in Notes and Practice: Friction and The Normal Force PDF Solutions  Video From Class
• Complete the "real life problem" at the end of the handout.  See example first, in the Solutions.
• Solve this spool car practice problem:
• Coming Soon... Spool Car Analysis -- Use video analysis to create a graph of position vs time for a spool car that starts and ends at rest.  Then use the graph to find the car's average acceleration (for the acceleration phase) and average negative acceleration (for the deceleration phase).  Last, use those accelerations and a balance (digital or triple beam) to find the net force and individual forces acting on your spool car during its acceleration and deceleration phases.  Make a diagram for each phase (speeding up, slowing down) showing individual and net forces, mass, and average acceleration.

Homework:

Class 64: Thursday, 4/14/22

Warm Up:

1. Which can you throw with more force, a Wiffle Ball® (0.045kg), a baseball (0.145kg), or a shot put (5.45kg)?  Or is there no difference?  Explain your thinking. Some calculations -- don't peek before thinking.

2. What limits the amount of force that you can apply when you throw an object?

Today:

Homework:

• None.  Relax!  After break we will pick up where we left off.

Class 63: Tuesday, 4/12/22

Warm Up:

1.  How fast does chalk fall? Is it faster than a cat?...

2.  Sometimes people celebrate special occasions by firing guns into the air.  Is this safe?

3. Why don't clouds fall out of the sky?

Today:

• **Notice:  late homework will no longer be accepted, except in the case of absences.  But remember that missing homework won't count as a zero.  If you don't do your homework on time, your tests and projects will just count more.  Homework will count for up to 30% of your grade this quarter (or 0% if you don't do any of it on time).
• Check/review the homework.
• Notes and Practice: Friction and The Normal Force PDF Solutions  Video from class
• Work time -- discuss quarter grade wrap-up

Homework:

Class 62: Friday, 4/8/22

Warm Up:

According to this article, emergency clinic records of 132 cats that jumped from windows of buildings showed a 90% survival rate.  The average drop was 5.5 floors.

Injuries increased with increasing heights up to 7 floors. When cats fell from over 7 floors, they actually suffered from “less injuries.”  Can you explain this surprising finding?

Today:

• Reminder #1:  Over spring break, I am going to consolidate all quarter 3 grades into one assignment.  If you have any missing assignments, get them done by next Friday.  Your quarter three grade will be locked in as of next Friday.
• Return the Newton Sled activity, and discuss the answers.
• Notes and Practice -- Newton's 2nd Law and Terminal Velocity PDF  Videos from Class -- Part 1 Part 2
• Near the end of class, return tests and release the test solution videos (to help you prepare for the retake).  The retake will be next Thursday.  If you can't make it to class that day, email me ahead of time to come up with another time.  The test must be retaken before break, if you're going to retake it.

Homework:

Class 61: Wednesday, 4/6/22

Warm Up:   It is possible to remove a sheet paper from under a dry erase pen without touching or tipping the pen.  How can one do this without tipping the pen?  Why does the pen usually fall?

Today:

• Notice #1:  Over spring break, I am going to consolidate all quarter 3 grades into one assignment.  If you have any missing assignments, get them done by next Friday.  Your quarter three grade will be locked in as of next Friday.
• Notice #2:  Due to the high number of students who were absent for the test, I won't be returning the tests until Friday.  If you missed the test you must take it during class today or on Friday.  There will be a retake next Thursday.  If you have not taken the first test by Friday, you will have to take the retake next Thursday, and you will not have a chance to take the test again.
• Newton Sled Activity PDF
• Complete the activity and answer the questions.  We will discuss the answers.

Homework:

• None

Class 60: Monday, 4/4/22

Warm Up:   What will happen if I poke a knife through a potato, hold both objects in the air with the knife pointing downward, and then hammer the butt of the knife into the potato?  Why?

Today:

• Test
• Newton Sled Activity

Homework:

• None

Class 59: Thursday, 3/31/22

Warm Up:   There is a heavy object suspended from the ceiling by a string.  Another segment of the same string is hanging downward from the object.  I am going to pull on the bottom string until one of the two strings breaks.  Which string is going to break first?  Why?

Today:

Homework:

• Study for Monday's test

• Videos:

• Videos:

Class 58: Tuesday, 3/29/22

Warm Up:

Here's the data for the fastest car in the class (on Friday).  What was its average acceleration?  What was its average speed over the final foot?

 Start time (s) 2nd tape time (s) Final Time (s) 5m Total Time (s) Average Acceleration (m/s/s) Velocity for last foot (m/s) Velocity of Last foot (mph) 1.605 3.143 3.205

Today:

Homework:

• If you want, you can retake the lesson starter quiz from last class (no new quiz).

Class 57: Friday, 3/25/22

Warm Up:

Consider the case of this ball.  At t = 0s, the ball is free-falling directly upward at a height of 10m, with a speed of 20m/s.  Sketch graphs of the ball's position, velocity, and acceleration (vs. time) over the next 4 seconds.

Today:

• Lesson Starter Quiz, attendance
• Check/discuss the homework
• Work on the Spool Tractor Challenge: (see last class for construction details)
1. Practice until you are pleased with your tractor's speed and performance.  When you are ready for the "official run," tell Mr. Stapleton so that he can video your tractor while you video your tractor.
2. Place the front of your tractor's wire on the blue starting tape.
3. Take a slow motion video of your tractor.  [Mr. Stapleton will take his own video at the same time.]  The video must show...
• Your tractor's wire crossing the middle tape (this must be clear, so stand near the end of the car's run)
• Your tractor'swire crossing the final tape
4. Edit your video so that it is all slow motion, and trim off any parts before it moves or after its wire crosses the last tape.
5. Use the Vernier Video Analysis App to analyze the video.
1. Open settings (gear wheel) and change the frame rate to 240 -- unless your phone has a different slow motion frame rate.
2.  Find the starting time and the times at which the wire crosses the middle and end tapes.
6. Use those times to calculate (just like the starter quiz and homework #5 asked you to do):
• Your tractor'saverage acceleration over the entire distance (distance = 5m)
• Your cartractor's average velocity between the 2nd and last tapes (distance = 0.305m)
7. On a sheet of paper (or using this form), clearly show your calculations and write down your answers.  Turn them in to Mr. Stapleton.  Your grade will be based on how close your calculations are to Mr. Stapleton's calculations [He will use his video to do the same calculations.]
• Start the test review.  It's due next class.

Homework:

Class 56: Wednesday, 3/23/22

Warm Up:

1.  How old is someone who has lived a billion seconds?  Have you lived that long?

2.  What is the significance of 1 billion heartbeats?

Today:

Homework:

• Finish this Practice -- unit conversions PDF  Solutions

• The lesson starter quiz will be similar to numbers 7-9 on the homework, except that the units and numbers may be different.  You will have to do two conversions.

Class 55: Thursday, 3/17/22

Warm Up:

Suppose a ball is placed carefully at the top of a ramp and released.  The ramp is 6m long, and it takes 3 seconds for the ball to roll down to the other end of the ramp.

1.  Does it seem reasonable to assume that the ball will accelerate the entire time?

2.  What is the ball's average velocity?

3.  What is the ball's initial velocity? (at the moment it is released)

4.  What is the ball's final velocity (as it reaches the bottom of the ramp)?

5.  What is the ball's acceleration?

6.  Use this scenario to create a formula for the ball's acceleration and displacement.

Today:

• Lesson Starter Quiz, attendance, return papers
• Check/discuss the homework
• Notes:  "Free-Fall, More Kinematics Formulas, and Kinematics Problems" PDF  video of notes from class
• Begin the Spool Tractor Challenge: (video -- spool tractor assembly)
• According to this source, the world record for a rubber band car is 5m in 2.82s.  If the acceleration of this car was constant, what was its top speed?  What was its acceleration?
• Build a spool tractor and practice with it to achieve the fastest possible speed over a 5m distance.  When you're ready, video the tractor's performance in slow motion (while Mr. Stapleton makes his own video of the same event).  Make sure that you get a good view of the tractor crossing the final floor tile.  Use the Vernier app to calculate the tractor's top speed (across the last floor tile) and its acceleration.  Show your data and calculations on a sheet of paper and turn it in.   For 100%, your calculations must be within 10% of Mr. Stapleton's calculations.

Homework:

Class 54: Tuesday, 3/15/22

Warm Up:

1. For letter a, on the right describe what an object could be doing in order to have both positive velocity and positive acceleration.

2.  Do the same for the rest of the letters.

Today:

• Return papers.
• Discuss homework and lesson starter quizzes.
• Practice together -- work on acceleration graph drawing at the end of the notes PDF
• Finish and turn in the Acceleration Video Activity:  Use the Vernier Video Analysis App to create  graphs of position vs. time.  Then find acceleration.  Make the two videos described below.  Here are the instructions.  Here's a video showing what to do
• A dense object thrown straight up (and falling straight down).  Find the ball's acceleration on the way up and on the way down.
• A student running, starting from a standstill.  See if you can accelerate as fast over 5 meters as a 2020 Corvette (8.1m/s2) or a 2020 Ford F-150 (4.25m/s2).
• Begin the Spool Tractor Challenge:
• Build a spool tractor and practice with it to achieve the fastest possible speed.
• According to this source, the world record for a rubber band car is 5m in 2.82s.

Homework:

Class 53: Friday, 3/11/22

Warm Up:   What is a spool tractor?  How does one work?

Today:

• Lesson Starter Quiz, return last quiz
• Finish your graphs from last class.  Here's a good example.
•  Acceleration Video Activity:  Use the Vernier Video Analysis App to create  graphs of position vs. time.  Then find acceleration.  Make the two videos described below.  Here are the instructions.
• A dense object thrown straight up (and falling straight down).  Find the ball's acceleration on the way up and on the way down.
• A student running, starting from a standstill.  See if you can accelerate as fast over 5 meters as a 2020 Corvette (8.1m/s2) or a 2020 Ford F-150 (4.25m/s2).

Homework:

Class 52: Wednesday, 3/9/22

Warm Up:

1.  Assuming that the man in the picture is 2m tall, and the frame rate of the camera was the usual 30 frames per second, what was the approximate maximum speed of the object?

2.  Based on your answers, do you think the assumption of 30 frames per second was too low, too high, or about right?

Today:

• Lesson Starter Quiz, return last quiz
• Check/review the homework (
• Motion Detector Graphing Activity
• In a group of up to 3 people, use a motion detector to create position vs. time graphs.
• Constant Positive Velocity
• Constant Negative Velocity
• Positive Acceleration
• Negative Acceleration
• Print each graph (position graph only), and label them according to what they are supposed to show.
• Show your calculations of velocity for two different intervals.  Then use those velocities to calculate acceleration.
• 95% for correct calculations and completion.  +5% if you can get the values of at least two graphs within 0.25 of 1 (e.g. 1m/s, -1m/s, 1m/s2, -1m/s2).  +10% if you can get all of your graphs within 0.25 of 1.

Homework:

• Prepare for the lesson starter quiz -- see the homework for class 50, below.  Next class' lesson starter quiz will be a repeat of the one described there.  But I will be choosing a different mix of velocity and position graphs to match.
Class 51: Monday, 3/7/22

Warm Up:

The sets of dots on the right represent frames of video taken of two different balls that are falling from the sky.  The video camera takes pictures at a constant rate of 30 fps (frames per second).  One of the balls is free-falling, and the other is attached to a parachute.

1. Which ball has the parachute?

2. How can you tell?

Today:

Homework:

• Finish the velocity and acceleration calculations on Motion Calculations and Graphs worksheet (PDF Solutions  For video help, watch the linked videos above.
• Next class' lesson starter quiz will require you to calculate acceleration from a position vs. time graph (like today's assignment).

Class 50: Thursday, 3/3/22

Warm Up:   Someone's velocity was graphed over a time of 5 seconds.  Create a position v/s time graph for that same person over that same time period.  Assume that the person starts from a position of zero meters.

Today:

Homework:

• Practice for the lesson starter quiz -- complete the position or velocity graph for 1-5, 7, and 8 from the Acceleration and Motion Graphing Notes handout.  Here's a video showing how to draw these graphs.  On the lesson starter quiz, you will only have to match position and velocity graphs, not draw them.  Here is a scan of the answers.
Class 49: Wednesday, 2/16/22

Warm Up:

The graph on the right shows the positions at different times for seven different people, relative to a motion detector at the 0m mark.  Which person (people) was (were)...
1. moving at a constant speed
2. moving toward the sensor
3. not moving at all
4. accelerating
5. decelerating
6. accelerating the fastest
7. moving at the fastest constant speed

Today:

• Lesson Starter Quiz
• **Announcement -- starting with today's lesson starter quiz, all lesson starter quizzes must be made up within two weeks (unless they are missed due to an excused absense or excused tardy).
• A1/2 -- check/review the motion matching activity questions
• Kinematics Intro Notes  PDF  Filled-in Notes
• Complete #5-8 on page 4 of the Kinematics Intro notes
• Practice for the lesson starter quiz

Homework:

• Study for the lesson starter quiz.  The quiz will require you to use a position vs time graph to create a velocity graph. Here's a video showing an example quiz and solutions.
• Complete #5-8 on page 4 of the Kinematics Intro notes, if you didn't finish it during class
Class 48: Monday, 2/14/22

Warm Up:   If you're trying to throw a Frisbee as far as possible, some good advice is to "keep the fast side down."  What does that mean?  Which side of the Frisbee is the fast side?

Today:

• Lesson Starter Quiz -- Due within 4  minutes after class starts.
• Return last class' quiz
• Next class' quiz? -- I will clarify at some point today
• Return/discuss tests.  Optional test retake on Friday.
• New Unit -- Kinematics (Velocity, Speed, Acceleration)

Homework:

• Study for the lesson starter quiz.  The lesson starter quiz will ask you how to match graphs from today's activities with descriptions of how the graphed object moved.  The descriptions will use phrases like...
• Move away from the sensor
• Move toward the sensor
• Speed up
• Slow down
• Stop
• If you want to retake any page(s) of the test, plan to do that on Friday.  The retake will not be the same as the original test.  It will come from the test review, just as the test did.  You can expect the number of questions and total points to be the same.  Here's the test review  (pdf version)   and the answers to the test review (Answers).
Class 47: Thursday, 2/10/22

Warm Up:

Spin one of the "sprotating cylinders" by pressing one end until it squirts out from under your finger.  Try pressing the other end.

1. When the cylinder is spinning, why do you only see the symbol that you press?

2. A bicycle rolls to our right at a speed of 3m/s (about 7mph).  What is the speed of...

a. ...a point on the top of one of the bicycle tires?

b. ...the center of each bicycle tire?

c.  ...a point at the bottom of one of the bicycle tires?

Slow motion

Today:

• Lesson Starter Quiz -- Due within 4  minutes after class starts.
• Return last class' quiz
• Next class' quiz? -- I will clarify at some point today
• Test

Homework:

• Study for the lesson starter quiz.  Unless I change the plan, the quiz will be very similar to warm-up question #2, above.  The bottom of the tire never moves.  The middle moves as fast as the bicycle, and the top moves twice as fast as the bicycle.
Class 46: Tuesday, 2/8/22

Warm Up:

1.  What is the advantage of polarized glasses?

2.  How do they work?

Today:

• Lesson Starter Quiz -- Due within 4  minutes after class starts.
• Return last class' quiz
• Next class' quiz? -- I will clarify at some point today
• Check the first two pages of the test review.

Homework:

• Study for the lesson starter quiz and the test.  The lesson starter quiz will be question #3 from "check your understanding," at the bottom of this web page.
Class 45: Wednesday, 2/2/22

Warm Up:

1.  What is a mirage?

2.  What do you think causes mirages?

Today:

• Lesson Starter Quiz -- Due within 4  minutes after class starts.
• Return last class' quiz
• Next class' quiz? -- I will clarify at some point today

Homework:

Class 44: Monday, 1/31/22

Warm Up:   The diagram on the right shows the path of earthquake waves as they travel through the Earth.  FYI, p-waves are "pressure" waves, and they are longitudinal.  S-waves are "sinusoidal," and they are transverse.

1.  Does the diagram show reflection, refraction, or both?

2.  What happens to the speed of earthquake waves as they travel deeper into the mantle?

3.  Which layer of the Earth has the highest index of refraction (n)?

4.  Do you see anything that looks wrong?

5.  How do we know the Earth has these layers, if we have never drilled through the mantle?

Today:

• Lesson Starter Quiz -- Due within 4  minutes after class starts.
• Return last class' quiz
• Next class' quiz? -- I will clarify at some point today
• Last of the Optics Notes -- Scattering, Human Vision, and Rainbows
• Build a parabolic mirror --
• In groups of 2-3, create a parabolic mirror that can focus all parallel beams within a 2 inch diameter circle.
• Prove that your parabolic mirror can heat an object using sunlight.

Homework:

Class 43: Thursday, 1/27/22

Warm Up:   We already discussed the mnemonic "Roy G. Biv."  This is an introduction to another mnemonic -- one that will help you remember which wavelengths of light are more susceptible to scattering.

1.  What's a "mnemonic?"

2.  What does Roy G. Biv help us remember?

3.  Which of the two arrows on the right do you think will be more likely to penetrate deep into the target?

4.  Which arrow is like blue light, and which arrow is like red light?

5.  Instead of passing through a material, "scattered" waves get bounced around in random directions. Which color is most likely to be bounced around or "scattered" by Earth's atmosphere -- red or blue?  Which color is best at penetrating the Earth's atmosphere?

Today:

Homework:

Class 42: Tuesday, 1/25/22

Warm Up:

1.  How many examples of reflection do you see in the graphic on the right?

2.  How many examples of refraction?

3.  What does this graphic tell you about refraction?

Today:

Homework:

• None -- except studying for the lesson starter quiz
Class 41: Wednesday, 1/19/22

Warm Up:   The spearfisher in the picture is trying to spear a fish.  When the spearfisher looks into the water, the fish appears to be in the location shown in the picture.  But the fish really isn't there.

1. Draw a dotted line from the fish's eye to the spearfisher's eye.  This represents the apparent path of a ray of light.

2. Accounting for refraction of the light ray, draw a realistic path of the ray of light between the fish's eye and the spearfisher's eye.

3. Sketch the actual position of the fish.

4. If you're trying to spear a fish that you see in the water, where should you aim?

Today:

• Lesson Starter Quiz -- Due within 4  minutes after class starts.
• Talk about next class' quiz.
• Refraction and Reflection Practice with ray boxes
• Finish it
• Finish #14-19 of the refraction notes.  Do more if we have time.

Homework:

Class 41: Wednesday, 1/19/22

Warm Up:

1. In the diagram, an "incident ray" of light hits the surface of some water.  Identify...

a) The "normal"

b) The angle of incidence

c) The angle of reflection

d) The angle of refraction

2. Clarify what will be on the quiz next class.

Today:

1. New Policies:
• Lesson Starter Quiz
• When you enter the classroom, you will find a stack of short and simple quizzes on the front table.  You will have until four minutes after the bell to complete and turn in your quiz.
• At four minutes after the bell, I will share the answers to the quiz.
• If your quiz is not submitted on time, you can take the quiz during FLEX.  It will be your responsibility to have your advisor sign you up.
• If you miss the quiz for a legitimate reason, make sure that you enter class with an "excused" blue slip.  This will be your proof.
• I will provide the answers to the next day's quiz questions at some point during class.  It's likely that I will provide those answers along with the warm-up.
• You must wear a mask in a way that covers your nose and mouth at all times in this classroom except...
• When you are actively chewing or swallowing food or drink (or within 5 seconds of beginning or ending such an activity).
• When you take off your mask for quick (under 5 seconds) adjustments.  No two such time periods can occur in the same minute.
• Starting on Friday, for the first two weeks of this semester (last day = 1/27) you will get one "free" warning per class. [If you need to engineer a mask solution, figure it out before next class.]
• After your warning, or after the first two weeks of the semester, you will be sent to the main office, and I will dial zero to let the office know that you are on the way.
• [Note that I reserve the right to change these policies.  If that happens I will notify you in advance.  I may add an extra period of one "free" warning per week.]
2. Look over exams.  Then return.
3. Notes -- Reflection and Refraction ("Wave behaviors," p.2 through #18 on page 6). Handout  Filled in notes
4. Lab -- Refraction and Reflection Practice with ray boxes

Homework:

• Be ready for your lesson starter quiz on Friday, before 8:04.
Class 40: Friday, 1/7/22

Warm Up:   **For this to make sense, I need to tell you something very strange and special about light...

Fred is conducting a laser experiment on a very, very, very fast train.  He attaches a mirror to the roof of the train car and shines a quick pulse of laser light directly upward at the mirror.  Hank is standing still outside the train.  The train car is made of glass, so Hank can see the whole thing.

The pulse of laser light goes up, reflects off of the mirror, and then goes back down to the floor.  There's enough dust in the air to make the laser pulse visible.

1)  If Fred and Hank were to draw the laser pulse's "flight path" (as each of them sees it), what would each of them draw?

2)  Who would see light travel a greater distance?

3)  Assuming that the speed of the laser light is the same for both observers, who sees it travel for the longest amount of time?

4) Guess how many tardies have been recorded in A1/2 during the first 39 classes?

Today:

1. Disassemble guitars -- after you've turned in your project slideshow
2. Calculating potential impact on your grade.  There will be no retakes of the midterm.
3. Last minute check-in regarding the midterm.
• How long are exams?  Can you leave early?
• What should you bring to exams?
4. A1/2 Heads-up regarding next semester -- arriving on time, in particular
5. Check on missing assignments
• Guitar project
• other?

Homework:

• Study, prepare a notecard
Class 39: Wednesday, 1/5/22

Warm Up:   Suppose you have a shirt that says "shirt" on the front.  When you look at your shirt in a mirror, which of these do you see?  Why don't you see the other one?  In other words, why do mirrors seem to "flip" images one way, but not the other?  What's going on? Here's a hint...

Today:

• Check midterm practice
• Hand out notecards.  You may write notes to use on the test.  You may use both sides of a 3"x5" notecard.  These notes must be handwritten by you.  You may write or draw anything that you think will be helpful.  You may not use someone else's note card.
• If you choose not to use a notecard, I will add 2% to your exam grade.
• Discuss what would be most useful on a notecard.

Homework:

• Study, prepare a notecard.
Class 38: Monday, 1/3/22

Warm Up:

The diagram below shows top views of the same boy looking into mirrors.  On the right, the mirror is a simple flat mirror.  On the left, the mirror is two separate mirrors arranged at right angles.  The boy has one blue eye and one green eye.

When he looks in the mirrors, where will his blue eye appear to be?  Why?

Today:

• Submit or Revise Electric Guitar Projects
• Finish midterm practice (due on Wednesday)

Homework:

• Midterm practice
Class 37: Tuesday, 12/21/21

Warm Up:

1.  Explain how this dad turns this pool into a "volcano."

2.  Is the Tacoma Narrows Bridge collapse an example of resonance?

Today:

Homework:

• Get some rest!
Class 36: Friday, 12/17/21

Warm Up:   How do people break glass with their voices?

Today:

Homework:

• Make sure that you're going to finish the project.  It's due on Tuesday.
Class 35: Wednesday, 12/15/21

Warm Up:

1. If you're standing next to a race track, what do you hear as the cars pass you?

a.  Their pitch changes from high to low.

b.  Their pitch changes from low to high.

c.  There is no change in pitch.

2.  Why?

3.  What causes sonic booms?

Today:

• Please complete this form.  We have talked about one of the questions, but not the other.  Just take your best guess.
• Return Quizzes -- retake opportunity on Friday.
• Guitar Project work:

Homework:

• If you're taking the quiz retake on Friday, study.  Make sure that you can do everything in this video.
Class 34: Monday, 12/13/21

1. Explain how movement of the guitar string is turned into sound waves coming out of the speaker.

2. Why is it neccesary to amplify the sound?  Why isn't the string loud enough by itself?

Today:

• Quiz
• Finish the guitars
1. Assemble and confirm that they work
2. Mark the frets (so that each fret has a frequency 1.0595 times higher than the one before) -- Get help from Mr. Stapleton.
3. Get confirmation that your fret marks are correct (have Mr. Stapleton check), and then make nice, dark marks with a Sharpie.
4. Label the fret marks with note numbers for a major key.  Do this with pencil first.  Get your numbers verified.  Then use a Sharpie.  Do this on the side of the neck "above" the string, when the nut is on your left and the saddle is on your right.  Write "Major" somewhere in this area, near the nut.
5. Both classes -- label the fret marks with their minor key numbers.  Do this on the other side of the string, opposite the major key numbers.
• Guitar Project work:

Homework:

• None, unless you need to study to retake the quiz at some point.
Class 33: Tuesday, 12/7/21

Warm Up:  If you see lightning strike a point 1 mile away, how long can you expect to wait before you hear thunder?  Why?

Today:

• Return the practice quizzes.  Go over the answers and make a video explaining the solutions.  Next class there will be a real quiz with the same kinds of questions.
• Finish the guitars
1. Assemble and confirm that they work
2. Mark the frets (so that each fret has a frequency 1.0595 times higher than the one before) -- Get help from Mr. Stapleton.
3. Get confirmation that your fret marks are correct (have Mr. Stapleton check), and then make nice, dark marks with a Sharpie.
4. Label the fret marks with note numbers for a major key.  Do this with pencil first.  Get your numbers verified.  Then use a Sharpie.  Do this on the side of the neck "above" the string, when the nut is on your left and the saddle is on your right.  Write "Major" somewhere in this area, near the nut.
5. A3/4 only -- Label the fret marks with their minor key numbers.  Do this on the other side of the string, opposite the major key numbers.
• Make a song video
1. Find a song to play.  You will get extra points if you play a song that is not on my list.  But it has to be recognizable, correct, and more difficult than something like "Hot Cross Buns."
2. Determine whether your song is in a major key or a minor key.  Play the song using the correct group of notes on your guitar.  Keep in mind that there may be a few "accidentals" -- notes that aren't in the same key as the rest of the song.
3. Figure out what key your're playing in.  If you're using the numbered notes, the key name is the same as the note for your open string.  You can find that note by using a tuner, like this online option.  If you're interested, here's the song sheet (note number notation) from 2014.

Homework:

• Study for the quiz next class.  It will have the same types of questions as the practice quiz.
Class 33: Tuesday, 12/7/21

Warm Up:  Remember that ordinary air pressure is about 14.7psi...

1.  What does "psi" mean?

2.  According to the table below, the "sound amplitude" of a .30-06 rifle fired at a distance of 1m is about 1psi.  What is the air pressure (in psi) in one of the sound wave's compressions?  What is the air pressure  in one of the sound wave's rarefactions?

3.  According to the table, there is a limit to how loud an undistorted sound can be.  Why can't sounds keep getting louder and louder forever?

 Source of sound (in air) Sound Pressure -- amplitude (psi) Volume in Decibels, calculated by 20*LogP/Po Po (threshold of hearing, in psi) Loudest Pressure divided by Quietest Audible Pressure Shockwave (distorted sound waves > 1 atm; waveform valleys are clipped at zero pressure) 14.69543147 194.0956869 2.9E-09 5,067,390,163 Theoretical limit for undistorted sound at 1 atmosphere environmental pressure 14.69543147 194.0956869 Stun grenades 2.900652647 180.0019545 Simple open-ended thermoacoustic device[6] 1.830166788 176.0018534 .30-06 rifle being fired 1 m to shooter's side 1.053662074 171.206067 M1 Garand rifle being fired at 1 m 0.728498912 168.0006182 Rocket launch equipment acoustic tests 0.580130529 166.0225545 Jet engine at 30 m 0.091660624 149.9956962 Threshold of pain 0.009166062 129.9956962 Vuvuzela horn at 1 m 0.002900653 120.0019545 Hearing damage (possible) 0.002900653 120.0019545 Jet engine at 100 m 0.029006526 140.0019545 Non-electric chainsaw at 1 m 0.000913706 109.9681656 Jack hammer at 1 m 0.000290065 100.0019545 Traffic on a busy roadway at 10 m 9.15156E-05 89.98194182 Hearing damage (over long-term exposure, need not be continuous) 5.16316E-05 85.01035459 Passenger car at 10 m 2.90065E-05 80.00195455 EPA-identified maximum to protect against hearing loss and other disruptive effects from noise, such as sleep disturbance, stress, learning detriment, etc. #NUM! Handheld electric mixer 5.51124E-06 65.57702656 Classroom Unit Ventilator TV (set at home level) at 1 m 2.90065E-06 60.00195455 Normal conversation at 1 m 2.90065E-06 60.00195455 Very calm room 9.19507E-08 30.02313979 Light leaf rustling, calm breathing 9.16606E-09 9.995696197 Auditory threshold at 1 kHz 2.90065E-09 0.001954545

Today:

Homework:

• None
Class 32: Friday, 12/3/21

Warm Up:  What does this picture have to do with waves and guitars?

ppt

Today:

• Check/review the homework.
• Finish the notes on standing waves and harmonics
• Finish the guitars.

Homework:

Class 31: Wednesday, 12/1/21

Warm Up:   What is a wave?  What is a sound?  How do ears work?

Today:

Homework:

• Complete #17-21, and #23 on pages 9-10 of the packet.
Class 30: Monday, 11/29/21

Warm Up:

What's happening in the "Amazing Water and Sound Experiment?"

Today:

• Turn in project videos (or let me know who you worked with).
• New Unit -- Sound and Waves
• Finish making guitars.

Homework:

Class 29: Thursday, 11/18/21

Warm Up:   What can you play on a one string guitar?

Today:

Homework:

• None
Class 28: Tuesday, 11/16/21

Warm Up:   How do guitarmakers determine the spacing of the frets on a guitar?

Today:

• Quiz
• Begin constructing your guitar.  Electric Guitar Instructions When it's constructed, "tune" it by making fret marks.  Use a tuner like this one to make pencil marks one musical tone apart (e.g. A, A#, G, G#...)

Homework:

• If you want to retake the quiz next class, study.
Class 27: Friday, 11/12/21

Warm Up:   How is an electric generator like an electric motor?

Today:

• Check out the quizlet
• Learn how to solder.  Before you make your pickup, show me that you can solder a magnet wire to a stranded wire -- and get continuity.
• Make magnetic pickups -- a type of electric generator.  Here's a link to the instruction page.

Homework:

• Study the quizlet.  We will have a brief quiz over this on Tuesday.
Class 26: Wednesday, 11/10/21

Warm Up:   How does this electric motor work?  Can it be improved?

Today:

• Return and disassemble remaining wiring projects.  Return parts for re-use (and the last two points on the project).
• Continue project work.  Next class we will probably begin working on magnetic pickups (a kind of generator), so see finish up what you can today.

Homework:

• None
Class 25: Monday, 11/8/21

Warm Up:   Your team must make a video that clearly showing your buzzer all of its parts -- and features you (your voice and "fingers," at least) explaining how it works.  What do you think is the easiest way to make and turn in this video?

Today:

• Return and disassemble remaining wiring projects.  Return parts for re-use (and the last two points on the project).
• Work on the Solenoid Buzzer Project
• If you're done with the solenoid buzzer, submit it.  Then return all of your materials (wire goes on cardboard, clearly labeled with "10m of 28 gauge magnet wire."  Then begin the motor or speaker project.

Homework:

• None
Class 24: Thursday, 11/4/21

Warm Up:

1.  Is there anything wrong with the diagram on the right?

Today:

• Return and disassemble wiring projects.  Return parts for re-use (and the last two points on the project).
• If your wiring project is not finished, simply draw the rest of the wires, LEDs, etc.  Then label everything as if the wiring and LEDs were real -- and as if they worked.  Then turn in your project.
• Magnetism Notes PDF  Filled-in notes  Video of notes during class
• Solenoid Buzzer Project

Homework:

• None
Class 23: Tuesday, 11/2/21

Warm Up:   How does this solenoid-powered buzzer work?

Today:

• Discuss the upcoming units and projects...
• Electricity & Magnetism Projects:  Complete at least two of the following projects.   One project must be the magnetic pickup, because we will use that in the next unit to make an electric guitar.  For each project, you must make a short explanatory video explaining how your object works. You can work on these projects alone or in pairs.
• Choice Projects (complete at least 1)
1. Solenoid Buzzer:  Watch this instructional video showing how to make a Solenoid Buzzer.  Draw a sketch of a solenoid buzzer design that uses only the materials below:
•  wood, nails, hot glue/glue guns, drill/drill bits, sheet metal screws, enameled wire (10m of 28 gauge), sandpaper (and belt sander), saw (not really necessary), strips of springy magnetizable steel (approx 0.5" wide, 3" long), and a D.C. power source (set betwen 3V and 6V).
• With those materials, you will have to make a working solenoid buzzer, as shown in the video.
2. Motor
3. Speaker (a form of simple motor)
• Required Project:  Magnetic Pickup (a form of generator)
• Waves project -- make a single string electric guitar (a.k.a. the electric "Diddleybow")

Homework:

• None
Class 22: Friday, 10/29/21

Warm Up:   None -- try to wrap up the project today

Today:

• Finish the Wiring Project
• Return some old quizzes
• If you finish the wiring project, start E&M (electricity and magnetism) project #1 -- build a solenoid buzzer.
• Watch this instructional video showing how to make a Solenoid Buzzer.  Draw a sketch of a solenoid buzzer design that uses only the materials below:
•  wood, 2 nails, hot glue/glue gun, duct tape, 10m of 28 gauge enameled magnet wire, sandpaper, sander, saw, 1 thin strip of steel steel (approx 0.5" wide, 3" long), and a D.C. power source.
• With those materials, you will have to make a working solenoid buzzer -- alone or in pairs.

Homework:

• None
Class 21: Wednesday, 10/27/21

Warm Up:   What is a solenoid?  How does it work?

Today:

• Work time -- finish the wiring project and turn in your model.
• If you're done early, begin the first magnetism project...
• Watch this instructional video showing how to make a Solenoid Buzzer.  Draw a sketch of a solenoid buzzer design that uses only the materials below:
•  wood, nails, hot glue/glue guns, duct tape, enameled wire, sandpaper, saw, strips of magnetizable steel (approx 0.5" wide, 3" long), and a D.C. power source.
• With those materials, you will have to make a working solenoid buzzer -- alone or in pairs.  You may cut, glue, or tape things, but you will not be allowed to nail or drill.  Nailing and drilling are not necessary.

Homework:

• None
Class 20: Monday, 10/25/21

Warm Up:

When electric current flows through an electric motor, a force is produced, causing motion.

An electric motor forced into motion generates electric current.

I have three identical corded drills and one driver bit.  With no additional materials, how can we power two of the drills by plugging just one of them into the wall?

Today:

•  Work time -- finish the project and turn in your model.
• Next Unit -- Electricity and Magnetism

Homework:

• None
Class 19: Wednesday, 10/20/21

Warm Up:

What is a Jacob's Ladder?  What is its purpose?

Today:

• How to make good connections
• How to avoid short circuits
• Color coding with bulbs -- and why
• What to turn in

Homework:

• None
Class 18: Tuesday, 10/19/21

Warm Up:   The pictures on the right show breaker panels.

1. What is the purpose of a breaker?

2. How does an electrician decide how many breakers are needed?

3.  Why are there different kinds of breakers?

Today:

Homework:

• None
Class 17: Friday, 10/15/21

Warm Up:

1.  Why is the guy in the video wearing a metal suit?

2.  Why are the sparks jagged?

3.  What else do you notice the sparks doing?

Today:

• Quiz
• IM TC  Jagged spark Jacob's ladder?  our tc?
• If there's time...You're going to be designing and wiring a model of a simple (but comfortable) electrically-powered cabin.  Let's brainstorm a list of basic electrical needs.

Homework:

• Quiz on Friday.  Study.
Class 17: Wednesday, 10/13/21

Warm Up:   Let's build the circuits on the right, and find the missing information, with the PhET DC Circuit Kit.

Today:

Homework:

• Quiz on Friday.  Study.
Class 16: Thursday, 10/07/21

Warm Up:   The purpose of a fuse is to open a circuit when the current gets too high.  How can we set up a demonstration of this with light bulbs, a power source, and a fuse?

Today:

Homework:

• None
Class 15: Tuesday, 10/05/21

Warm Up:   What can Tango and Cash teach us about electricity?

Today:

Homework:

• None
Class 14: Friday, 9/30/21

Warm Up:   The deceptively complicated case of the electrified pickle...

Why does the pickle light up Why does it light up on just one end?  Is it always the same end?

Today:

• Return and review quizzes
• Finish the PhET simulation

Homework:

• None
Class 13: Wednesday, 9/29/21

Warm Up:

1. How can you start a fire with a 9 Volt Battery and some steel?

2.  Ohm's Law says V = IR.  Guess what each of the letters means.  Solve for I.  Solve for R.

3.  P = VI.  Guess what each of the letters means.  Solve for V.  Solve for R.

Today:

Homework:

• None
Class 12: Monday, 9/27/21

Warm Up:   Can we recreate some of the experiments performed by the "brainiacs?"  Do we want to?

Today:

• Review the practice quiz through #13.
• Finish the practice quiz and discuss the answers.  Practice Quiz answers  Talk about Wednesday's quiz.  Maybe do some verbal quizzing.
• The new unit -- Electric Current and Circuits
• Look at a D.C. circuit -- pHet simulation?

Online Textbook Links:   Chapter 19, Introduction to Electrical Circuits

Homework:

• Study for quiz next class
Class 11: Thursday, 9/23/21

Warm Up:   There is a "pith ball" hanging next to the Van de Graaff generator.  The pith ball is foam that is covered with a conductive, metallic paint.  What do you think will happen when the Vand de Graaff generator is turned on?  Why?

Today:

Homework:

• Complete 1-13 on the practice quiz  PDF
Class 10: Tuesday, 9/21/21

Warm Up:   Which of the following can we say with certainty?  Why?

A)  The balloons have the same net charge

B)  The cat and the foam "peanuts" have opposite net charges.

C)  Both A and B are correct.

D)  None of these answers is (are) correct.

Today:

Homework:

• None
Class 9: Friday, 9/15/21

Warm Up:

How does a Van de Graaff Generator Work?

Today:

Homework:

• None, unless you would like to retake your quiz.  If you want to do a retake, study the Quizlets.
Class 8: Wednesday, 9/13/21

Warm Up:

1.  If you rub a balloon on your head and then hold it next to your hair, your hair is attracted to the balloon.  Why?

2.  Your hair may also stand on end after being rubbed by a balloon.  Why?

3.  The balloon may stick to the wall or ceiling.  Why?

4.  This all works better in drier air.  Why?

5.  What events contributed to this gas station fire?

Today:

Homework:

• None
Class 7: Monday, 9/13/21

Warm Up:   None -- change of plans due to weather forecast

Today:

• Rocket rebuild, launch, and maybe find time aloft.
• We're not measuring burnout velocity, so you don't need to measure your rocket's height.
• Quiz on Wednesday, instead of today.
• Remember to mark the quizlet complete when you've finished it.

Homework:

• None
Class 6: Thursday, 9/9/21

Warm Up:

1.  Which do you think lasts longer, the flight up or the flight down?

2.  Why does adding weight to a rocket make it go higher?

Today:

• Take a look at some sensor data.
• Complete the Rocket Analysis
• Make a decision -- Do we want to rebuild and launch one more time, or do we want to go ahead and start on electricity?

Homework:

• There are two quizlet assignments in Google Classroom.  Study both quizlets.  You should study them until you know the information, but when you've studied each one at least once, you can mark each assignment complete.
• There will be a simple quiz next class.  The quiz will have the same questions as the quizlets,  plus you will have to measure a line in appropriate metric units of your choice.  If you don't do well on the quiz, you can have another try.
Class 5: Tuesday, 9/7/21

Warm Up:  Video Practice -- If you have a phone, take it out and get a video of this object that I am about to launch in the room.  Keeping your camera still the whole time, video with the highest frame rate (slowest motion) that your phone will allow.  Try to capture the entire flight.

Today:

• Finish assembly and measure rockets.
• Make sure that there's ventilation in the probe area.
• Fill out your data sheet and turn it in.
• Launch rockets
• Video your rocket with a phone.  Record the entire flight in slow motion.  We have a Samsung Galaxy that you can use.
• Measure altitude with the Pocketlab Voyager sensor.

Homework: None.

Class 4: Thursday, 9/2/21

Warm Up:

1.  Why can't we "see our breath" right now?

2.  When we do see our breath, what are we actually seeing?

3.  I made a video showing how I can make my breath visible at will.  Can you tell how I did it?

Today:

Class 3: Tuesday, 8/31/21

Warm Up:

The air around us is pressurized to about 14.7psi.

1.  What does 14.7psi mean?

2.  What evidence is there that there is air pressure around us?

3.  We are going to measure the heights of your rocket flights using a pressure sensor.  How will a pressure sensor tell the height of the rocket?

Today:

• Take attendance
• Student info sheet -- A3/4 Only
• Water Rocket Design:
• Provided materials -- 1 meter of duct tape, Two 2-liter bottles, DVDs, Hot Glue
• **New requirement: your rocket must incorporate a chamber for storing an air pressure sensor.  The
• Get bottles and decide which one you will use for a pressure chamber (fuselage).  Don't cut into this bottle!
• Use the digital calipers to measure the nozzle diameter (same as the launcher plug diameter, which is easier to measure).
• Find the pressure chamber bottle diameter (using the big calipers)
• Use the Clifford Heath's simulation to determine the best combination of water and dry mass.  Write down the best volume of water and the best dry mass.
• Measure the mass of your pressure chamber bottle.  Subtract it from your dry mass to figure out how much mass your fins, tape, and other additions should have.
• **Make a sketch of rocket design.  On the diagram, include the following:
• Names of your group members
• Labels for the materials that you plan to use for fins, weights, and other purposes
• Write down the best amount of water and the best dry mass, according to Clifford Heath's simulator.  Write: "water volume = ____" and "dry mass = ______"

Homework: None

Class 2: Friday, 8/27/21

Warm Up:

According to this article, emergency clinic records of 132 cats that jumped from windows of buildings showed a 90% survival rate.  The average drop was 5.5 floors.

Injuries increased with increasing heights up to 7 floors. When cats fell from over 7 floors, they actually suffered from “less injuries.”

1.  What's happening here?
2.  What determines the rate at which something falls?

Today:

Homework: If you want to bring in any extra materials for rocket construction, round them up and bring them to class on Tuesday.

Class 1: Wednesday, 8/25/21

Physics 100: Mr. Stapleton

Warm Up:

1.  Suppose you're absolutely still.  What do you need to do in order move your body to another location?

2.  Suppose a spaceship is floating in space, absolutely still.  What does it need to do in to another location?

Today:

Homework: None