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.
Hi all. I’m out for another day or two (extreme sore throat, no, not caronavirus!) From the feedback I’ve received on Remind, it looks like most groups have completed, or are successful at gathering, the data.
Please take Monday to complete gathering data and entering it into a spreadsheet.
I’m proud of you all working together to figure out how to work the photogates and collect the data. It’s unusual for you to have this many days without your regular teacher, and it seems you are doing a great job.
It looks like some of you tried to copy the spreadsheet template on Friday, but were not logged in to your school account. I have set the sharing so you can now access it from any Google account. Click here if you need it.
Today: Enter a link to your spreadsheet in the form at the bottom (even if you have not completed it).
Here’s a screenshot of the template. There are no formulas written, so you will have to write those yourself. Remember that each students needs to have their own copy of the spreadsheet.
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.
Please finish data collection for both collisions an explosions. Remember that an explosion uses the spring on one cart, and both carts start with zero momentum.
Data analysis
Analyze all your trials, calculating the momentum and kinetic energy changes for each scenario. If you would like, you can use a Google spreadsheet template here.
Each member of the group needs to make their own spreadsheet. If you prefer to use Excel, you can download the Google Sheet as an Excel spreadsheet.
Homework
Complete all the data analysis in a spreadsheet, and develop a conclusion about the conservation of momentum and kinetic energy in each of your scenarios.
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.
https://youtu.be/H3UQiuDej38
File Name: Roller-Coaster-Physics-video-notes.pdf
PDF Loading...
Other energy videos you may enjoy
Is energy conserved on a galactic scale? Watch the videos below:
Review your lab goals and procedures from Tuesday’s description. Your goal today is to collect pre- and post- collision data for both of your carts in four different variations (e.g. changing the mass, changing the velocity, changing the direction of the cars).
Data collection
Set up your ramp so you can record the data both before and after the collision.
Before you start collecting data, make a bullet list of all the variables you will measure. Include the following for each variable:
where you will find that number (on what device)
the units for each measurements
the uncertainty of each measurement (remember that with digital readouts, we assume ±1 of the lowest decimal place provided by the measuring device).
Create a data table in your lab book, including three trials for your four different collision types.
Collect your data, then enter it into a Google or Excel spreadsheet (we will want to do more processing of the data than Desmos can handle, although you may want to ‘copy and paste’ the data into Desmos later for plotting).
After you have completed collecting data for your four collisions, start with your explosion data collection if you have time.
Feel free to leave comments/questions below, where they may get more response than being one of the 6,000+ comments on the Youtube page (or add comments there).
The Vernier Photogates use a beam of light to detect objects between the two ‘arms.’ LoggerPro identifies the gate state as “Open” or “Closed.”
Open implies that nothing is blocking the light beam
Closed implies there is something blocking the light beam.
In most cases, we want to know the time that the gate is closed.
Determining the speed of an object that passes through the photogate
Attach a photogate to a ringstand, then adjust it so a flag mounted on your cart will break the beam of light.
Measure the length of the object that will pass through photogate. When the object passes through the photogate, it measures how long the beam is blocked. The object’s speed (at the position of the photogate) is determined by dividing the length of the object by the blocked time.
This video should walk you through setting up Logger Pro for ‘gate timing.’ The interface she uses different than our LabQuest Mini, but the sensor set up should be the same.
Remember that you will need to attach both photogates, so you can get the velocity of each cart.
More detailed information on the photogates can be found on Vernier’s website.
Here’s a video with more deep background on how the Photogate works.
These labs will take about three days to complete. Tuesday will be preparing/practicing. Wednesday will be completing Part 2 and 3. Thursday will be sharing your trends/conclusions with the class, where we will look for overall trends/conclusions.
Prelab discussion (much yesterday)
Part 1: Qualitative construction of momentum
Part 2: Collision of Carts
Part 3: “Explosion” of Carts
Postlab discussion
Part 2: Collision of Carts
You will be provided with two carts and various masses. You will need to measure the speed of the carts right before they collide and right after they collide.
Working with your group (record all in your lab book):
Develop a method of measuring/calculating the velocity of two carts right before and after they collide.
Practice with your method until you are confident you can accurately measure the needed velocities.
Determine the uncertainty in each of your measurements.
Plan out at least four different types of collisions. This may involve
Initial directions
Masses
Develop a data table to record your data for all your variations.
Run your trials.
Analyze your data
Present trends in a reflection section.
Part 3: Explosions
Explosions are defined as interactions where the initial velocity of each cart is zero.
Repeat the steps you used for Part 2
Video tutorial
Just a fun video showing Newton’s Cradle made with bowling balls!
