Describe a tsunami, when they occur, and why they can be so destructive.
It looks like I’ll be back on Thursday. Still a rough throat, but the doc thinks I’ll be ready by then. I’ll probably have a wireless mic so I don’t have to strain my voice 😊 .
Today’s work
Read through the earthquake pamphlet and complete the worksheet. Remember to reflect on about both energy and waves as you complete the earthquake packet. That’s what earthquakes are all about.
Resources
Reading pamphlet
Putting Down Roots in Earthquake Country: Your handbook for the San Francisco Bay Region, printed by US Geological Survey
Hi all. I’m out for another day or two (extreme sore throat, no, not caronavirus!)
Warm up
Draw an energy bar chart set for the mousetrap car as it goes from (1) fully wound up to (2) moving across the floor and finally (3) stopped on the floor.
Today you will have a reading and worksheet to practice on energy and working. Hopefully I’ll be back tomorrow so we can start on the mousetrap cars.
If you do not complete today’s assignment in class (it’s a shorter day), please complete it for homework.
Using physics, explain why the first hill on a roller coaster always the highest.
Designing your mousetrap car
Next week you will build, test, and the mousetrap car. As you build it, you will also determine the work done by the mousetrap spring by measuring the force and distance the mousetrap arm moves.
Watch the following videos, and take notes about ideas that techniques you may use for your car (we will start with materials on Monday).
Record your notes in today’s exit ticket area and the “Three things I learned this week” section of your bookends sheet.
Before you leave today, turn in your bookends sheet (make sure your name is on it!)
Homework
Start thinking about how you might customize your mousetrap car. Each group will receive the following items, extras are are up to you. If you want to use special materials, collect them over the weekend so you can use them on Monday.
One small mousetrap (larger rat traps are not allowed)
A light board about 8″ long by 3″ wide (you may replace this if you prefer a different design)
Dental floss or similar string
One set of plastic wheels with axle
One pair of CDs
Hot glue
Paint stirrer stick (two lengths available), to extend your mousetrap bar and tie your string to.
More videos you might want to view
Another video showing many student-built mousetrap cars.
Sketch the following roller coaster, then draw energy bar charts for Position A, B, and C.
No stamp today, but you will get credit for completing the warmup section for today.
Lesson
Video day. What the main video and answer the questions on the handout. You may ask the sub to pause the video if you need time to complete lengthier questions.
File Name: Roller-Coaster-Physics-video-notes.pdf
Other energy videos you may enjoy
Is energy conserved on a galactic scale? Watch the videos below:
In this activity, you will use a PhET simulation to observe wave interactions and develop the wave speed equation. You can use the simulation below, or if that doesn’t work well, you can find it directly here.
Copy and complete the following sentence
by entering one word:
Water
waves travel in the shape of a ______, sound and light waves travel in the
shape of a _______.
Some notes you should have
Sound is a longitudinal (also called compression or pressure) wave.
In a wave diagram, the lines represent crests (areas of high pressure).
Sound is created by repeated changes in pressure.
Sound is really another way energy is stored (in the high pressure areas where more energy is stored in the kinetic energy of the particles.
Sound is called simple harmonic motion (more about that when we discuss harmony).
While we usually draw sound waves as expanding circles, the sound actually travels as spheres.
Doppler effect:
The sound wave doesn’t actually change, it is just the wavelength people hear that changes.
Long waves = low notes; Short waves = high notes.
The equation that relates wavelength, frequency, and speed is:
Velocity = frequency * wavelength
Frequency and wavelength have an inverse relationship.
Speed of sound is called Mach 1, fastest jet fighter is about Mach 3.
Speed of sound is about 750 MPH (343 meters per second).
Speed of sound changes with temperature: Hotter = higher speed.
“Ultimate Doppler effect” is Mach 1, the speed of sound.
At this point, each wave “piles up” on the wave crest before it, creating a sonic boom with very high sound energy.
Some airplane speeds:
Typical passenger jet: Between 0.5-0.7
The Concorde, the first ‘super-sonic’ (faster than sound) was developed in the 1980’s to lessen airplane travel time. They flew at about Mach 2.
Jet fighters can fly around Mach 3.
Sonic booms
When an object moves faster than the speed of sound, the air pressure ‘piles up’ and creates a very large boom.
Exit ticket
Copy and complete the following sentences by selecting one of the bold words: In the Doppler effect, we detect waves from a source moving towards us as higher/lower pitch, because their wavelengths are shortened/lengthened.
Friday: Standing waves and harmonics
Warm up
Copy and complete the following sentences by selecting one of the bold words: In a sonic boom, “the ultimate Doppler effect,” we the loud boom is created because high/low sound pressure builds up at the front of the jet, and the jet is moving faster/slower than the speed of sound.
