**Next year: Have no lab instructions and have students DESIGN their own experiment
Big Questions:
“How do we measure force in a reliable and repeatable way?"
"What is the relationship between the mass of an object and the force needed to hold it in place?”
** Your instructor will show you how to calibrate the electronic force probes and get an average of the data points using the LabQuest2 probes**
Create an organized table in Notability of the mass (in grams and in kilograms) and the force needed to support it at rest.
Hang a brass mass from the force probe and measure the force needed to support it at rest. Record this data in your chart.
Repeat this step three more times with different masses (for a total of four data points) and have every person at your table switch lab roles each time you collect new data.
Use the Graphical Analysis App to make a plot of mass (in kilograms, on the x-axis) vs. force (in Newtons, on the y-axis). Label your axes and include units.
Make a best-fit line to your data set and determine the SLOPE of this line using the LINEAR FIT Function in Graphical Analysis.
Save the image of your Graphical Analysis Graph and insert it into your Notability File.
Pyramid Lab
**Next year: Rename "Ramp Lab" . . .Associate with the moving truck scenario . . . Use a heavier mass object and the ramp from the floor to the top of the table.
Big Questions:
“How can force be manipulated using a simple machine?"
"What pattern do you observe regarding the relationship between force and distance
in a simple machine? "
Pre-Lab:
Use the stack of physics books to place your ramp at an angle.
measure and record the height of the ramp at the point that it touches the stack of books
Place a cart on the ramp and add additional brass or aluminum masses.
measure and record the total mass of the cart and metal masses (an empty cart is 250 g)
Plug in the force probe and "zero" it.
Lab:
Trial #1:
Begin with the rear of the cart lined up vertically with the point where the ramp meets the edge of the table.
Pull the cart steadily up the ramp using a constant force. Stop when the rear of the cart lines up vertically with the point where the ramp meets the edge of the books.
Record the average force needed to pull the cart up the ramp (in Newtons) and the distance you applied this force (in meters).
Make a BAR GRAPH of the FORCE (N) vs. the DISTANCE you applied the force (convert cm to METERS!). Shade in the AREA bounded by this graph - a rectangle. (Unfortunately, you CANNOT make a BAR Graph with Graphical Analysis - so you will have to draw this graph).
Trial #2:
Readjust the position of the ramp so it makes a larger angle compared trial 1. The high side of the ramp should still be on the stack of three books -- we're NOT trying to change the HEIGHT of the ramp, nor are we changing the STARTING height of the cart, we're just adjusting the ramp ANGLE and therefore the ramp LENGTH.
Begin with the rear of the cart lined up vertically with the point where the ramp meets the edge of the table
Pull the cart steadily up the ramp using a constant force. Stop when the rear of the cart lines up vertically with the point where the ramp meets the edge of the books.
Record the average force needed to pull the cart up the ramp (in Newtons) and the distance you applied this force (in meters).
Make a BAR GRAPH of the FORCE (N) vs. the DISTANCE you applied the force (convert cm to METERS!). Shade in the AREA bounded by this graph. (Unfortunately, you CANNOT make a BAR Graph with Graphical Analysis - so you will have to draw this graph).
Trial #3:
Readjust the position of the ramp so it makes an even larger angle compared to trial 2.
Begin with the rear of the cart lined up vertically with the point where the ramp meets the edge of the table
Pull the cart steadily up the ramp using a constant force. Stop when the rear of the cart lines up vertically with the point where the ramp meets the edge of the books.
Record the average force needed to pull the cart up the ramp (in Newtons) and the distance you applied this force (in meters).
Make a NEW BAR GRAPH of this FORCE (N) with vs. the DISTANCE you applied the force (convert cm to METERS!). Shade in the AREA bounded by this graph.
Post - Lab Analysis:
Do you see any relationships between these three AREAS?
Could you write down the AREA as an equation relating force (F) and distance (d)?
What are the UNITS in which the areas would be represented? (This might take some thought...)
PULLEY CHALLENGE:
Part 1:
How much force does it take to slowly lift a 200g brass mass 10 cm without using the pulley system?
Part 2:
Using the equation you derived in the Pyramid Lab, what length of string will you have to pull in order to get the mass to rise 10 cm using only 1.0N of Force?
Design and build a moveable pulley system that will allow you to lift a 200 g brass mass from the table to a height of 10 cm with only (roughly!) 1.0 N of force (as shown in class). (You can reference the image below to assist you with lifting your pulley)
Stretching Spring Lab
Big Questions:
“How does the force it takes to stretch a spring depend on the
AMOUNT by which you stretch it?”
"How can we store energy to do work for us later?"
Lab:
Hook the spring on the force probe.
Zero out your force probe.
Stretch the spring 1 cm (0.01 m) and then begin measuring the force from the probe (measure the force for about 10 seconds and average the values using "analyze statistics"). Record this data neatly in a table [distance stretch (m) and force needed to stretch (N)].
Repeat the previous step for 2 cm, 3 cm, 4cm, and 5cm of stretching.
Graphs:
Part 1
In Graphical Analysis, make a PLOT of the DISTANCE STRETCHED (m) on the x-axis and FORCE NEEDED TO STRETCH (N) on the y-axis for your data collected.
Use the Linear Fit function to insert a best fit line for your data and derive the slope.
We'll call this slope of a force vs. distance line for an elastic object the 'k value' or 'elastic constant' or 'spring constant'. It tells us how many Newtons of force the elastic object provides for every meter it is stretched (whether it's a spring, rubber band, or any other elastic material).
Use the equation of a line, y = mx + b, to derive an equation relating the spring constant of the rubber band (k), the distance stretched (x), and the force needed to stretch it (F).
Part 2
Determine how much energy you store in the stretched spring when you stretch it by 1 cm, 2 cm, 3 cm, 4 cm, and 5 cm. Recall that energy is the AREA of a force vs distance graph, so think about the SHAPE of the area under the graph. You will have to MANUALLY calculate the AREA, as graphical analysis cannot perform this function.
Try to develop a SECOND EQUATION that relates Elastic Potential Energy (Us), force (F), distance stretched (x), and the elastic constant (k).
Post-Lab Analysis:
1. What does the slope represent? What are the units of the slope in this case?
2. What happens to the force when you stretch the spring further?
3. What happens to the energy stored in the spring when you stretch it further?
Oscillating Spring Lab
Big Question:
"Can we transform Elastic Potential Energy into other forms of energy?"
"What does it mean for energy to be conserved?"
Pre-Lab: Make a prediction
Sketch one cycle of an oscillating spring.
Identify points in the cycle with Max Elastic Potential Energy. Why did you choose these points?
Identify points in the cycle with Max Kinetic Energy. . Why did you choose these points?
Use these points to help you create two new sketches:
(1) Sketch the graph of Kinetic Energy vs. Time
(2) On the same graph, sketch the graph of Elastic Potential Energy vs. Time
Compare the two graphs, do you notice any trends?
Write one sentence describing the exchange of elastic potential and kinetic energy over time based on your sketches.
Lab: Confirm your prediction
Using the Logger Pro Software on the computer, open the experiment file “17c Energy in SHM.” Three data columns have been set up in this experiment file (kinetic energy, elastic potential energy, and the sum of these two individual energies).
You will need to modify the settings for the energy calculations.
Double click on the Kinetic Energy box on the lower right side of the screen.
Substitute your hanging mass of 0.5 kg.Then click done.
Double click on the Elastic Potential Energy box on the lower right side of the screen.
Substitute in the spring constant "k" value 30 N/m for the blue spring. Then click done.
3. With the mass hanging from the spring and at rest, click to zero the Motion Detector.
**From now on, all distances will be measured relative to this equilibrium position. When the mass moves closer to the detector, the position reported will be negative.
4. Start the mass oscillating in a vertical direction only, by pulling it down about 5-10 cm below equilibrium. Click the play button to gather position, velocity, and energy data.
5. Click on the y-axis label of the velocity graph to choose another column for plotting. Click on “More” to see all of the columns. Uncheck the velocity column and select the kinetic energy and potential energy columns. Click to display the new plot(s).
TAKE A PICTURE OF YOUR COMPUTER SCREEN FOR FUTURE REFERENCE
Post-Lab Analysis: How do these graphs represent the Conservation of Energy?
Compare your two Pre-Lab Energy Graph Sketches to the Energy Graphs on your computer screen. Be sure you compare to a single cycle beginning at the same point in the motion as your predictions. **You may need to zoom in to observe the energy plots by selecting Analyze from menu and click on Zoom.
If the total energy is conserved in this system, how should the sum of the kinetic and potential energies vary with time?
Check your prediction. Click on the y-axis label of the position graph to choose another column for plotting. Click on “More” and select the total energy column in addition to the other energy columns (that is click on the little squares so that Kinetic Energy (KE), Potential Energy (PE), and Total Energy (TE) will be displayed). Click to draw the new plot. (You might wish to enlarge graph displays).
From the shape of the Total energy vs. time plot, what can you conclude about the conservation of energy in your mass and spring system
When sketching the collision, make it very clear which objects are moving rightward and which are moving leftward before and after the collision -- we'll need this information later.
Use the equation p=mv to calculate momentum (remember, momentum is a vector!), K_{E}=1/2mv^{2} to calculate Kinetic Energy
Verify that the track is as level as possible and that you have two range finders plugged in which can "pick up" the motion of each of your two carts (RED and BLUE).
Verify that the red line on the LabQuest matches the red car and the blue line matches the blue car (you'll need to press "collect" in order to test this)
Lab
Elastic Collision
Set up the two carts so their spring launchers are facing one another -- this ensures they will "bounce off" one another.
Start the carts about 30 cm from the range finders.
Send the two carts at each other so they collide.
Measure the speed (v) of the RED cart BEFORE the collision.
Measure the speed (v) of the RED cart AFTER the collision.
Measure the speed (v) of the BLUE cart BEFORE the collision.
Measure the speed (v) of the BLUE cart AFTER the collision
1. Calculate the FRACTIONAL amount of ENERGY that entered or left the system (was it 10%? 20%? 50%? 100%?) -- do this with the following formula:
% difference = [(TOTAL ENERGY_AFTER - TOTAL ENERGY_BEFORE)/(TOTAL ENERGY BEFORE)] x 100%
Record this amount
2. Calculate the FRACTIONAL amount of MOMENTUM that entered or left the system (was it 10%? 20%? 50%? 100%?) -- do this with the following formula:
% difference = [(TOTAL MOMENTUM_AFTER - TOTAL MOMENTUM_BEFORE)/(TOTAL MOMENTUM BEFORE )] x 100
Record this amount
3. Which quantity is better conserved in an elastic collision: ENERGY OR MOMENTUM?
Inelastic Collision
1. Calculate the FRACTIONAL amount of ENERGY that entered or left the system (was it 10%? 20%? 50%? 100%?) -- do this with the following formula:
% difference = [(TOTAL ENERGY_AFTER - TOTAL ENERGY_BEFORE)/(TOTAL ENERGY BEFORE)] x 100%
Record this amount
2. Calculate the FRACTIONAL amount of MOMENTUM that entered or left the system (was it 10%? 20%? 50%? 100%?) -- do this with the following formula:
% difference = [(TOTAL MOMENTUM_AFTER - TOTAL MOMENTUM_BEFORE)/(TOTAL MOMENTUM BEFORE )] x 100
Record this amount
3. Which quantity is better conserved in an inelastic collision: ENERGY OR MOMENTUM?
***If time permits: repeat each experiment with different masses in each cart.
Friction Lab
Big Questions:
What is friction?
How does it relate to the atomic description of the universe?
How does static friction differ from kinetic friction?
Pre-Lab:
Pick one person in your group to take their shoe off -- notice the material it has on the bottom. Take a photo of the bottom of the shoe and record some qualitative observations about the material.
Using the force probe, calculate the mass of the shoe (this is review - think about it!). Record this value.
Part I: Collect Data
Hold the force probe horizontally and Zero it.
Place the shoe flat on the table and hook the force probe onto the shoe. Orient the force probe horizontally so you are pulling PARALLEL to the table -- it is important you not angle the force probe upward or downward.
Create a data chart of Mass of Shoe, Force STATIC Friction, Force KINETIC friction to organize your data.
Total Mass of Shoe (kg)
Force of Gravity (N)
Force of STATIC friction (N)
Force of KINETIC friction (N)
Start with at least 1kg of mass
IV: Mass of the shoe
Change the mass of the shoe by adding various brass masses inside the shoe (**NOTE: THE MORE MASS THE BETTER!)
Make sure to add the brass mass value to the original mass of the shoe (calculated in the pre-lab). Record this value in your data chart
DV: Force of Friction
Measure how much force it takes for the shoe to SLIP & START SLIDING.
Collect data as you GRADUALLY increase the amount of force until the shoe starts to slide.
You can use "Analyze => Statistics" to get the maximum force. Record this value in your data chart as the FORCE of STATIC FRICTION.
DO NOT DELETE or ALTER YOUR LAB QUEST SCREEN! You will need it for the next part described below. . .
Now, highlight the straight line on your force probe (where the force is contant) --> Analyze --> Statistics --> Mean. Record the mean as your FORCE OF KINETIC FRICTION.
Repeat for a total of FIVE TRIALS.
Analyze Data
Graph 1: Weight of Shoe vs Static Friction Force
Using the Graphical Analysis App, graph the WEIGHT of the shoe on the horizontal axis of the tray. Recall that weight is the force of gravity, so use F_{g} = mg to calculate this.
On the vertical axis, plot the MAXIMUM STATIC FRICTION FORCE, F_{f-s}
Insert an image of this graph into your Notability Notes
Graph 2: Weight of Shoe vs Kinetic Friction Force
Using the Graphical Analysis App, graph the WEIGHT on the horizontal axis of the tray.
On the vertical axis, plot the MEAN KINETIC FRICTION FORCE, F_{f-k}
_{Insert an image of this graph into your Notability Notes}
Conclusion
What pattern do your two graphs reveal regarding the weight of the shoe and force of friction in general?
Determine an equation expressing the relationship between F_{f-s} and Fg
Determine a second equation expressing the relationship between F_{f-k} and F_{g}
**We will complete the post-Lab Analysis Day 3 of this week
Part III: Post-Lab Analysis
Revise both equations to express the relationship between friction and the normal force
What can we conclude about the relationship between static & kinetic friction?
Compare your graphs with another group. How do your slopes compare? What do you think the slope means?
Hover Disc - Interaction Diagrams
Big Question:
What does it mean to say "For every action, there is an equal and opposite reaction"?
What is the relationship between FORCE and ACCELERATION?
Pre-Lab:
Acceleration(a) is a change in velocity over a change in time
The units for acceleration are m/s/s or m/s^2
Acceleration is the SLOPE in a velocity vs time graph
Lab:
Measure the FORCE of the fan cart on various settings (LOW, MEDIUM, HIGH) using the force probe:
Make sure the fan cart is pointed directly down the track (not at an angle)
"Zero" the force probe
Set the Fan speed on "LOW"
Let the cart push against the force probe as shown in the picture on the right
Measure the average force using Analyze --> Statistics --> Mean
Take a screenshot
RECORD the FORCE for LOW setting in an organized chart like the one below.
Repeat the steps above for MEDIUM and HIGH fan settings.
Fan Cart
Setting
Acceleration
(m/s^2)
Force
(N)
LOW
MEDIUM
HIGH
2. Measure the ACCELERATION of the fan cart on various settings (LOW, MEDIUM, HIGH) using the Vernier Video Physics App:
Recording Acceleration of Fan Cart with Video Physics App
Start with the LOW fan setting
Open Vernier Video Physics App
Hit the (+) key --> choose TAKE A VIDEO
Use landscape mode
Make sure the fan cart will travel from left to right in your video
Line yourself up with the middle of the track and stand far enough away to see the cart's starting point and most of the track (see image on right)
Hold your iPad still while you record - DO NOT move your iPad while the fan cart moves
Press "Record" and have your lab partner release the cart to it moves rightward across the track
Rotate group members and have other group members repeat the steps above for the MEDIUM and HIGH settings so that each person takes a video
If you have more than three people, repeat the measurements for the high setting.
Analyzing Acceleration of Fan Cart with Video Physics App
Your teacher will lead you through a tutorial on analyzing your video
Set up Scale
Press on the scale icon (line with arrows on each side) --> Drag the white circle to one of the blue tape markers on your track --->Press to drop a point ---> Drag the white circle to the other blue tape marker n your track ---> Press to drop a point --> Press on SCALE and input Scale:0.4 Unit:m
Set up Origin
Click on Axis Icon (X & Y axis) ---> Drag green dot to the "origin" of your video & rotate if necessary
Make a Motion Map
Click on Plot Points icon (icon with the circle at the center) --->drag the white circle to "the pointy part" of the fan cart -->press to drop a point
Helpful hints
Click on the (>>) button 5-10 times to fast forward frames between dropping a point
Try to click at the same point on the fan cart as it moves
Create a Velocity vs Time graph
Click on the GRAPH icon (top right hand corner)
Click on the EXPORT icon (top right hand corner)
OPEN DATA IN . . .GRAPHICAL ANALYSIS
Graphical Analysis App Instructions
Click on the graph icon and hit "1 Graph"
Click on the Y-axis and check the on the X Velocity option ONLY
Press the "i" to add a title to your graph. The title should read "Force vs Acceleration for the Fan Cart on the Low Setting (FORCE: ____ N)
Generate a mathematical fit for your data
think about what the slope of a velocity vs time graph is
Take a screen shot of your graph and insert it into your notability notes
RECORD the ACCELERATION for LOW setting in your organized chart
Fan Cart
Setting
Acceleration
(m/s^2)
Force
(N)
LOW
MEDIUM
HIGH
Repeat the steps above for MEDIUM and HIGH fan settings.
Post-Lab Analysis:
On your whiteboard, create an Acceleration vs Force graph with your 3 data points for low, medium, high fan settings
Solve for the slope of your graph
Derive an equation relating Force and Acceleration
What do you think the slope of your equation represents?
Battery Buggy Lab
Big Questions: What are the necessary parameters for an object to travel at constant velocity?
Each group will be provided the following materials:
Battery Buggy
Video Physics APP
Masking tape
Meter stick
Let the vehicle move across table. Using the materials above, sketch the following in your Notability note:
A Motion Map of your Battery Buggy
A Position vs Time Graph of your Battery Buggy
A Velocity vs Time Graph of your Battery Buggy
Using your graphs, derive the answers to the following questions in your Notability note:
What is the velocity of the Battery Buggy?
What is the acceleration of the Battery Buggy?
What is the Net Force on the Battery Buggy?
Please explain the acceleration of the Battery Buggy with respect to Newton's 2nd Law (F=ma). Provide quantitative evidence to support your claim.
Force Plate Activity
Big Questions:
How do we analyze forces in two dimensions?
Your group has been given a force plate with three spring gauges (springs that measure force). Two of these gauges are visible, one is covered by tape.
What is a projectile? What is the general path of motion? Why?
Pre - Lab:
Practice using the Vernier Video Physics APP
Reference the instructions at the top of this webpage (4) Vernier Video Physics (for iOS) for more help
Lab - Part 1: (Complete in the Gym)
Use the Camera App (NOT Video Physics) to record a video of a launched ball (basketball shot)
You do NOT need to actually shoot at the rim. In fact, it will be easier to analyze if you just shoot an "air ball" anywhere in the gym.
Make sure you record your video perpendicular to the shot of the ball (side view). It will be easier to analyze our videos together as a group if you shoot "rightward".
Make sure you can see your entire body and the entire flight of the ball in the video.
Put a meter stick at your feet in the direction of the ball's motion (you will use this to set the scale for the video)
Use the Camera Roll app to trim your video so that the video begins with the ball just leaving your hands (it doesn't matter where the ball is when the video ends)
Lab - Part 2: (Complete in the Gym or for Homework)
Insert Video for Analysis
Go to Vernier Video Physics APP-->Hit the (+) key --> choose existing--->Pick your video
Set up origin
Step ahead in your video to the point when the ball has just left your hand (and become a projectile)
Click on the small x-y axis icon ---> Drag green dot to this point
See image on right
Set up Scale
Use the meter stick to find the point on your body 1 meter above the floor (this point should be visible in your video).
Press on the scale icon (line with arrows on each side) --> Drag the white circle to one end of the meter stick, touch the ground and tap ---> Drag to the white circle to the other end of the meter stick and tap ---> Check to make sure that the gray box says Scale: 1 Unit: m
Make a motion Map
Step ahead in your video to the point when the ball is on the origin
Click on Plot Points icon (icon with the circle at the center)
Drag the white circle to the CENTER of the basketball --> tap one time and a blue dot will appear and the video will advance one step
Drag the white circle to the CENTER of the basketball --> tap one time and a blue dot will appear and the video will advance one step
Continue this analysis until the ball hits the ground (or is no longer a projectile)
Write a Blog Post called "Charge Transfer & Interaction"
Add this photo to your blog
Explain at the atomic level how the comb/balloon became charged when you rubbed it on your hair (refer to the triboelectric series)
Explain at the atomic level how the comb/balloon attracts neutral water (physicsclassroom article should help with that)
Lemon Battery Lab
Big Questions: How is electricity generated and employed to do useful work?
Pre-Lab Discussion:
What is a battery?
What are the components necessary to creating a single-cell battery?
What is a volt?
How do can we measure voltage?
Lab:
From the knowledge you gained in your pre-lab discussion, build a basic single cell battery using a lemon, copper penny and zinc coated nail (as shown in the photo below):
How much voltage does your single cell lemon battery produce? Record your measurement in a chart like the one below:
Continue to connect single cell lemon batteries in series (as shown in the image below) until they produce enough current to light up a small LED bulb. Continue to record your data in the chart.
How much voltage do two lemon batteries in a series produce? three? four? How many volts does it take to light a small LED bulb?
Analysis:
Answer these reflection questions (use the provided links & search for other online resources)
Task 1: Build a simple circuit in the simulationWire up a single battery, light bulb, and a switch controlling it. Use a voltmeter to measure the voltage drop ACROSS the lightbulb. Break the wire (right-click on it at a junction) and put an AMMETER in the path. SHOW YOUR TEACHER!
a. Take a picture of your computer screen and add it to your Notability note. Then, draw the circuit schematic using circuit symbols next to the image. Label this "A Simple Circuit".
b. What do you think the Voltmeter reads? WHY?
c. What do you think the Ammeter reads? WHY?
Task 2: MEASURE RESISTANCE, VOLTAGE, and CURRENT in a SIMPLE CIRCUIT
a. Right click on the light bulb and input the electrical resistance value given by your instructor.
b. Use the voltmeter to measure the voltage drop ACROSS the lightbulb.
c. Break the wire (right-click on it at a junction) and put an AMMETER in the path to measure the current.
d. By right-clicking on the battery, change its voltage to a variety of values and measure the current using the AMMETER. Record your measurements in an organized chart in your notes.
Task 3: Determine the RELATIONSHIP between VOLTAGE, CURRENT, and RESISTANCE
a. Use your Graphical Analysis App to make a plot of your values for VOLTAGE (x-axis) vs CURRENT (y-axis) for your electrical resistance. (What fit do you need to model the data?). Check in with your instructor, then take a screenshot of this graph to put in your notes.
b.
On a WHITEBOARD, make a sketch of the graph, labeling all axes.
Use your graph and measurements to determine a relationship (an equation) relating the three quantities voltage (V), current (I), and resistance (R). Check in with your instructor and take a picture of your whiteboard model.
Resistors in Series vs Parallel
Big Question:
What is the difference between a circuit with resistors in series and resistors in parallel?
What must happen in order for electrons to move through the wires (current to flow)?
What happens to the current if you use a stronger magnet?
What happens to the current if you use more loops of wire?
What happens to the current if you use bigger loops of wire?
What happens to the current if you increase the flow of water?
What do you notice about the direction of the current?
Is the flowing water turning the magnet or the coil? Do you think it would it matter?
So how is energy being transferred here? What type of energy do we start with?
How does this connect to a dam, like O'Shaughnessy Dam at Hetch-Hetchy?
Can you think of other ways you could turn the magnet (or the loops) other than using the falling water?
ACTIVITY #2
Big Questions:
How are magnetism and electricity related?
Can we use electricity to generate magnets?
ELECTROMAGNET INQUIRY ACTIVITY:
Materials:
1 meter of wire
piece of sand paper
1 9 V battery
1 Switch
Alligator Clamps
1 Bar Magnet
Part 1
prepare the wire by sanding off about 1 inch of the insulation at each end (you should see the copper exposed)
create a short circuit with the switch in the off position
It is very important that the switch is in the off position. When the circuit is on, the wires will heat up quickly and the battery will drain quickly.
place the bar magnet below a section of the thin wire, and bend the section of wire so that it hovers ~1 cm above the bar magnet (see photo)
turn the switch on and off (but don't leave it on)
What do you observe?
reverse the direction of the current and turn the switch on and off (but don't leave it on)
create a short circuit with the switch in the off position
disconnect the thin wire and wrap into a coil with a diameter of a few centimeters (see photo on the right). Keep at least 10 cm straight on both sides of the coil (like arms)
connect the coil into the circuit with the loops hovering ~1 cm above the bar magnet (see photo)
turn the switch on and off (but don't leave it on)
What do you observe?
reverse the direction of the current and turn the switch on and off (but don't leave it on)
What do you observe?
Lecture:
How does a coil of current-carrying wire affect the magnetic field around it?
How can we determine whether an object has magnetism?
What happens if we cut a magnet in half?
What can we use to predict the direction of a magnetic force due to a magnetic field?
(1) In your NOTABILITY NOTES, describe the MAGNETIC DOMAINS of each of the following materials.
(a)NON-MAGNETIC Material (b)TEMPORARILY Magnetic Material (c)PERMANENTLY Magnetic Material
(2) The image below shows the magnetic field lines surrounding a bar magnet. What would happen to the magnetic field if you cut the bar magnet in half? Please create a sketch illustrating your prediction.
(3) What would happen if you bring the North Poles of two bar magnets close together? Please create a sketch illustrating your prediction.
Build a Motor
Big Question:
What direction will a moving charge get pushed by a magnetic field?
How can we apply what we've learned about electromagnetism to build a motor and explain how it works?
Part 1: Demo & Worksheet on the Magnetic Force
Part 2: Building & Explaining a Motor
Materials
1 9V Battery
1 Coil
1 Bar magnet
1 Switch
2 Paper clips for the "axle"
2 pieces of clay to hold the axles
2 Alligator Clamps
Construction
Put the bar magnet flat on the desk and put two pieces of clay on each side of the magnet about 10 cm apart.
Bend one side of the paper clips to make a "long arm" and firmly insert the long arms into the clay.
Slide the coil of wire into the paper clip such that it rests on the cradle of the paper clips above the magnet. The coil should be about 1 cm away from the magnet at its closest approach.
Use the two alligator clamps to connect the battery to the two paperclips.
Kick start the motor with your finger to get it spinning continuously.
When you have successfully got the motor to work – call your instructor over.
Helpful hints to get it spinning...
Is there good electrical contact between the paper clip and motor?
Is the coil balanced? Are the arms straight and evenly high?
Post-Lab Analysis:
Take a photo (or video) of your motor and insert it into Notability.
Describe how the motor is the opposite of the generator
After you show your instructor, take a picture of your whiteboard and insert into Notability.
The direction of the magnetic force can determined by using Right Hand Rule #2.
Light Lab
Big Questions:
What does it mean to say that light is an electromagnetic wave?
How fast do electromagnetic waves (light) travel?
Pre-Lab: Understand How Microwave Ovens Work and Determine the Frequency of the Microwaves
What frequency to microwaves ovens operate at? Why?
Record this frequency in your lab notes
Lab: Measure the Wavelength of a Microwave
Materials:
1 Paper Plate
~150 Chocolate Chips
1 Ruler
1 Pencil
Guding Steps:
Line up the chocolate chips on the plate so that they make 3 parallel rows next to each other, about 25cm long
Place the plate of chocolate chips in the microwave for less than 30 seconds (without the turntable).
Observe your chocolate chips to determine where the energy was most intense (these are called the antinodes of the wave)
Measure the wavelength in meters
Take a photo of this measurement and record it in your lab notes
Post Lab: Determine the Speed of Light Waves
Use the fundamental wave equation to solve for the speed of electromagnetic waves (light).
Look up the accepted value for the speed of light and calculate the percent error:
% error = |measured - accepted| / accepted x 100
Record your analysis in your lab notes
Reflection Lab
Big Question:
Do light waves (rays) behave in a predictable way?
What happens to light waves when they hit a flat mirror?
Set Up (photo 1)
Place the mirror on a piece of white paper, and trace the flat side.
Use a protractor to draw a normal line to the flat mirror
remember that normal means perpendicular
Experiment
Use the laser to send a wave of light to the mirror striking the exact point where you drew the normal line. This will create two waves, one incoming wave called the "incident ray" and one reflected wave called the "reflected ray"
Mark the point somewhere on the incident ray, such as it where it leaves the laser
Mark the point somewhere on the reflected ray, such as where it shines on the paper
Analysis
Use your marks to trace and label the incident ray and the reflected rays
Label and measure the angle of incidence
notice that we measure the angle from the normal line to the incident ray of light.
Label and measure the angle of reflection
notice that we measure the angle from the normal line to the reflected ray of light.
What happens to light waves when then go from one material to another?
Collect Data
Place a rectangular prism on a white piece of paper.
Use the light box to generate a single light ray. Allow the single ray to pass into the prism at an angle (see image to the right), and note the change in direction at the other end.
Repeat steps 2 & 3 for a new angle of incidence until you have five angles of incidence and five corresponding angles of refraction.
Analyze Data
Calculate the sine of each angle of incidence and each angle of refraction. Add these values to your table.
Using the "manual entry" feature in your Graphical Analysis App, make a plot of the SINE of the angle of refraction on the horizontal axis vs. the SINE of the angle of incidence on the vertical axis.
Derive an equation for this data. This is referred to as "Snell's Law".
Build a Speaker
Big Question: How can I harness motion (or other forms of energy) to make electricity & magnets?
Build a Speaker:
Use the coil you made for your Electric Motor .
Using the sandpaper, rub off the coating on the wire’s two ends – this will allow you a contact so that current will flow when you hook it up to the stereo.
The coils should be smooth and not overlap. Tape the coil of wire securely to bottom of the plate.
Tape the magnet to the bottom of the plate, in the center of your wire loop..
Take your speaker over to the stereo in the classroom. Make sure the volume is ALL THE WAY DOWN. Attach each alligator clip to each of your wire ends and tune to your favorite station.
Turn up the volume!
Recycle your speaker!! Return the paper plate, wire, and magnet to the table. Throw away the tape. Leave the table CLEANED UP.
Analysis:
Discuss how the speaker works to make you hear a sound with your lab partner and include a detailed description of your hypothesis in your lab notebook.
Palm Pipes Lab
Big Questions:
How can we tell something (like sound) is a wave if it is invisible or too small for us to see?
How do musical instruments work?
What's the difference between a woodwind & a stringed instrument?
Provide Students with a Palm Pipe of varying lengths:
Your task is to figure out what MUSICAL NOTE your palm pipe generates by completing the following steps:
Measure Length of the palm pipe (convert cm to m)
Measure the Diameter (convert cm to m)
Solve for WAVELENGTH using this equation: L=1/4(wavelength) -1/4(Diameter inside)
Solve for the FREQUENCY using the fundamental wave equation (velocity = frequency x wavelength) **remember what medium the sound is traveling in!
Confirm Frequency in Lab – using FFT & Microphone
Instructions:
Go to File -> Open -> Probes & Sensors -> Microphone -> fft
Remember ***Experiment -> Connect Interface -> LabPro -> Com1 if you can't collect data!
Use Wolfram Alpha to convert Frequency to a musical note
Try typing in a frequency like '349.2 Hz' and it will tell you the note (F in the 4th octave)
Record the note of your Palm Pipe & check with your teacher