I wrote this lab for IB Physics so the notation matches the standards in that curriculum. There is an editable version of the file at the bottom of this post if adjustments need to be made to the notation or equations to better fit the class. Part 1: ExploreThe first part of this investigation allows students to explore the different controls of the simulation and what settings result in objects floating or sinking. From there, the force vectors are turned on and force diagrams are created for an object floating and an object sitting on the bottom. Students should see that the net force is always zero but the combination of buoyancy, contact, and gravity are impacted by the overall scenario.
Part 2: LabIn the second half of this lab, equations are introduced and students discover where the different numbers in the simulation come from. The goal is for students to become comfortable with calculating weight and buoyant force when they have the support of the simulation to confirm their values. Eventually, they should be able to create a mathematical relationship to calculate the normal (contact) force for an object that sinks and rests on the bottom and develop an experiment using the simulation to determine the density of an unknown fluid.
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This activity is adopted from an awesome EarthScope Lesson (and their new online version) and students use real, live earthquake data to track how seismic waves travel through the planet, notice where they behave strangely, and use that strange behavior to map out the Earth's interior for themselves. This iteration of the investigation follows the main procedure of the original EarthScope activity but simplifies the calculations to make the task more accessible for a 9th grade earth science class. Set UpThis task requires students to access an activity sheet and have the ability to access on online seismogram viewer. In my classroom, we are 1:1 iPad so I provide the activity as a downloadable pdf and they use their device to complete the activity. In addition to the digital portion of the investigation, students will also need a printed "Earth Circles" page, scissors, and something to write with (markers work well). All of the necessary files are included at the bottom of this post. ActivitySelect an Earthquake to InvestigateUsing www.earthscope.org/app/gsv/, students click on a circle to access data from a recent earthquake. (The red circles represent the most recent quakes)  Mark Each Seismogram LocationEach colorful line represents a seismogram measuring the vibrations of the earthquake from a different location on Earth. These positions are measured as an angular distance in degrees (°). Students will click on each seismogram to determine the position of the station ( ____ degs away) and mark the locations with a dot on the Circle #1 of the "Earth Circles" printout to represent each of the stations measuring the quake. If they have access to colored markers or pencils, students like to match the star colors to the seismogram color so they don't lose their place but a single color will also function just fine :)  Mark Arrival Time for Each StationNotice that the vibrations reach the different stations at different times. After taking a screenshot of the seismogram data, students will draw a dot on each graph to represent the first indication of the earthquake waves at that station. An example is shown below…  Using the “Time Since the Earthquake” on the y-axis, students will then determine the time delay to measure the earthquake waves at the closest and farthest stations. This step is to help draw their attention to the values on the y-axis and recognize that the farther away the station is, the longer it takes to register a signal from an earthquake. Locate the shift in the trendStudents will notice that, in general, the farther away from the earthquake the station is, the longer the delay before the earthquake vibrations are detected. On their graph, they will also notice that for the last 4-6 stations, the pattern seems to shift and the waves arrive slightly later than expected suggesting that these waves were interrupted by something on their way through the earth  Using the graph, students should estimate the angle at which the waves start to appear slower than expected. In the example above, it is clear that it is somewhere between 100° and 115°, so this student might choose an angle somewhere in the middle like 107°. Draw lines and cut out Earth Circle #1Students draw lines on Circle #1 from 0° to the approximate angle (on top and bottom) where the waves noticeably slow down. They will then use scissors to cut out this shape. (This is the only cutting involved so they can probably share scissors) Based on the data, there must be something in this area of the earth slowing down the waves. The example shown matches the 107° angle that was estimated in the last step.
Trace Cutout onto Circle #2Once cut out, students will overlay the “pizza slice” cutout on Circle #2 with the point lined up with 0° and trace the straight cut-out lines.
Simulate more earthquakesTo better narrow down the area responsible for slowing down the waves, students can simulate other earthquakes by rotating and tracing the cutout with the point at intervals of 45°. In all, this should trace the shape 8 separate times and the result should start to resemble a star shape across the circle. This can also be achieved by students swapping shapes and tracing from random "starting points" to make it even more like they are tracking different earthquakes. This was my original plan but it made the step a little more complicated and time dependent for students that were at very different steps of the activity so I changed it to be tracing the same shape multiple times.  Locate the "slow down"You will notice that regardless of where you place the point of the cutout when you trace it, there will always be one area that never receives any lines. This "mysterious slowing" of the waves must occur in this area. With multiple tracings, students can trace a circle representing the blank area inside the earth. This circle represents the area in the earth’s interior that is interrupting the earthquake waves.  Calculate the Size of the CoreStudents will measure the size of the interior circle that they drew (core) compared to the overall circle #2 size and use these measurements to calculate the % of the Earth's diameter taken up by its core.  Is it the Inner or Outer Core?
Looking back at the earthquake data, and measured percentage of the core, is the inner or outer core most responsible for the unexpected slowing of the seismic waves? ReflectionOverall, I found that this activity did a nice job of guiding students through the analysis of the seismogram data and identifying the "unexpected slow down". There was a little confusion as I anticipated when it came to the step of tracing the cutout multiple times and using this to identify the size of the core. I made sure to wander the room and assist students by modeling one tracing for them when the time came and they usually picked it up quickly after that. AcknowledgementsThis activity is an iteration on a wonderful investigation by EarthScope. They also have a great web-based version that is worth checking out. The tool to access real earthquake data is what makes this activity so great and I truly appreciate all of the work that has gone into making this data so accessible. FilesThe files, including the editable "Earth Circles" and support slides are included below
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This activity fixes that misconception with nothing more than a strip of paper and a handful of folds. Students start by labeling one end "Sun" and the other "Pluto," then work their way inward — fold in half for Uranus, fold again for Neptune, again for Saturn — halving the distance over and over until the outer planets are spread across broad, generous sections of paper and the four inner planets are scrunched into a tiny sliver near the Sun. No rulers, no math, just a paper model that makes the true structure of the solar system impossible to un-see: it's mostly empty space, and the "inner solar system" we think of as roomy is actually a rounding error next to the gas giants. It's quick, it's hands-on, and it gets at the scale surprisingly effectively without any measurements. Versions of this activity exist elsewhere online but I wanted to share the slides that we put together to visually walk through the procedure. This activity is great for my 9th graders that struggle a little bit with the larger number math of outer space and I think it could work well in middle or even elementary school to introduce these concepts. Set upThe only set up required is to prepare strips of paper. When I run this in my classroom, I like each student to have their own set up so that everyone has something to work on. Strips of paper could be made with receipt paper or even toilet paper but I have usually just cut strips the long way from pieces of 11x17 paper. You can easily get 3-4 strips this way without any cutting and taping required :) ActivityThis version of the activity is communicated through a series of visual slides. It would be easy to add some follow up calculations to determine the scale for the model produced and extend it to determine the distance at this scale to the nearest star, Proxima Centari.          Files
AcknowledgementsI first heard about this simple approach of scaling the solar system from Chandler Beasley during a shareathon at the LIGO Internation Physics and Astronomy Program in 2025. I couldn't stop thinking about the simple hands on approach that allows students to interact with the concepts without getting lost in the math of it all. Click Here for More Earth & Space Resources
The ActivityThe beauty of this activity is that it is entirely self contained in a single print out. Since students will be quantifying area by cutting out the shapes and finding mass on an electronic balance, you will want to print this out on the thickest piece of cardstock that you can find to ensure that the cutouts are large enough to measure. 
"Measure" the Time Since each dot represents the location of the object each day, counting the number of dots reveals the number of days that the object was in each zone. In this way, students will find that each shape represents 13 days of the planet's orbit Measure the "Area" Finding the swept area in this ellipse segments mathematically is quite challenging, so this activity uses mass as a way to compare one area to another. Since the paper/cardstock should be a uniform thickness, larger area corresponds to a larger mass. The exact mass of these segments will depend on the cardstock thickness but the segments should only vary a couple hundredths of a gram (the main challenge is convincing students that their result is about as close to the same as one can measure for something like this) Describe the Speed The dots around the orbit resemble a dot diagram or stroboscopic photograph from physics. If students aren't familiar with this approach to showing motion, I just tell them that the faster an object is moving, the farther it moves between "pictures". This should help students "discover" that the closer the object is to the star, the faster it is moving. Discussion QuestionsOnce students had an opportunity to "collect their data" regarding this object's orbit, I invited the class to discuss the following questions:
After discussing these, it's nice to jump to the PhET simulation to see what this changing velocity looks like in action and how Kepler's 2nd Law predicts this. Files
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This iteration of the activity was written for a 9th grade earth science classroom but could also be successful with older high schoolers or advanced middle school students. The changes that have been made to this version focus on accessibility and student-paced investigation. The ActivityIn this activity, students work with 7 graphs, each showing a climate model in which only one forcing factor (orbital changes, solar variation, volcanic eruptions, aerosol pollution, greenhouse gases, land use, and ozone depletion) changes while the rest are held constant. From there, they layer those factors together, compare them against the real measured temperature record, and work out for themselves which ones actually match what we've observed over the past century. The goal is that students can gain a deeper understanding of the different mechanisms that impact Earth's climate and how greenhouse gases are the clear factor that is responsible for the warming trend over the past 100 years. To start the activity, each group of students should begin with a set of 12 climate model cards and organize them into three piles based on the symbol in the top left corner: Measured Temperature (thermometer icon), Forcing Factors (A-G), and Combined (1-3) The rest of this post will walk through the different steps of the activity with the student questions to help focus their investigation. Measured Temperature CardsThe first two cards represent a measured temperature anomaly as a global average across the past century. These are actually the only measured data in the set that don't come from a computer model and they will be used as a comparison point when analyzing the climate models later on.
Check-in Questions1. How much has the temperature changed in the 100 years between 1900 and 2000? 2. You show your younger brother this temperature graph and he comments that the data must be fake because there is no way that the average temperature is less than 1°C. How could you respond? Climate Model CardsEach of the climate model cards isolates a single forcing factor and graphs the temperature anomaly as if that factor were the only variable changing for the past century. The cards have a short description of the forcing factor on the back that will be helpful in responding to the check-in questions included in the activity. Students should notice that these graphs all have the same x-axis (year) but VERY different y-axis (temperature anomaly) scaling. More on this when comparing the graphs later on...
Check-in Questions3. In what layer of the atmosphere can you find the ozone layer? 4. Which three forcing factors impact the albedo/reflection of solar radiation? 5. Which of the forcing factors is responsible for periodic ice ages? 6. How many major volcanoes erupted between the years of 1960 and 2000? How do you know? 7. Which of the following is not considered a major greenhouse gas? a. Methane b. Carbon Dioxide c. Nitrous Oxide d. Hydrogen Students then use the general shape of the graphs to complete the table below by marking (✅) if each forcing factor has an overall cooling effect, warming effect, or no major effect on the global temperature. Students are usually surprised to learn that there are some factors that actually make the climate cooler.  It can be challenging to determine the relative impact of each of the factors when the graphs are all automatically scaled to fill the space provided. Putting these graphs on the same axis makes these factors much easier to compare.
Combining Forcing FactorsEach of the models (A-G) isolates one forcing factor to help compare them against each other. A helpful way to put some order to the data is to combine the models together while also isolating the natural forcings (A-C) from the human/anthropogenic factors (D-G). This will be helpful to see how adding the factors together results in the best-fitting approximation relative to the measured data. The typical takeaway is that students identify that natural factors are simply unable to explain the extent of the warming shown in the measured data. Students use the graph cards combining the forcing factors (1-3) to answer the following questions Graphs 1 and 2 combine the Human and Natural factors together to make one single graph. Use the table below to identify (✅) which factors are considered to be “Human” and which ones are “Natural”  9. Which factors seem to have the largest impact on the global temperature? Natural Forcings or Human Activity? 10. Looking at graph 3 combining ALL forcing factors, what is the cause of the downward spikes? 11. Which of the combined factors is closest in its prediction to the measured temperature over the same timeframe? Natural Forcings, Human Activity, or All Forcing Factors? 12. Looking back on all of the data, which single forcing factor (A-G) is the most significant contributor for the rise in the average temperature for the past 100 years? AcknowledgementsThis activity has been a favorite of mine since Dave Fish from the Perimeter Institute shared it at a session that I attended at the 2016 NSTA Convention in Atlanta. The work that he and the rest of the perimeter team have done for the "Evidence for Climate Change" resource is the backbone for this iteration of the activity. ReflectionI have used some variation of these climate models over the past decade and I typically guided my students through a series of questions as they each worked with their own set of cards. I have been longing to make this more student-led with questions that help direct their attention to important details and connections as they go. This way students have more control over their investigation and it frees me up for more informal and deeper questioning as I wander around the room. I've now used this iteration of the activity for my first two years of teaching 9th grade earth science. It's been great to see it hit the learning targets while also giving students more room to learn interactively. Files
These should be printed in color front to back with a short side flip (just make sure that the descriptions match the graph). I recommend printing in cardstock or laminating to make these sets reusable from class to class or year to year. They work best when cut into 12 individual cards (I make my first hour do the cutting for me ;))
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