Tropospheric Ozone Virtual Picture Lab

I created this lab during the summer when tropospheric ozone is really high in the Los Angeles area. I used ozone test strips from Carolina Biological and took pictures at various times of the day, near freeways and away from freeways. You can purchase strips from the link below or from Carolina.

I normally cover air pollution in the winter when we typically do not have much ozone AND we are a few miles from a freeway. This means no readings or hardly any readings on the test strips. So, I made this picture lab a few years ago for students as an inquiry way to figure out ozone patterns. It also saves a lot of money as test strips are expensive.

The best option for teachers is to make your own lab taking pictures in your area, because research shows student learn best with local data. But, hey, teachers have limited time so feel free to use my lab created in the Los Angeles area. My city is a suburb of Los Angeles and I often drive down to LA for museums, restaurants etc.

Here are the links to the lab:

Pictures that can be uploaded to Google Classroom for student use or printed in color.

Student worksheet for the lab.

Some hints if you use this lab and are not in the Los Angeles area:
The Getty Center is a famous art museum located next to the very busy 405 freeway in Los Angeles. It is near Hollywood.
SCV is the Santa Clarita Valley.
#15: Our city , Santa Clarita, is located between the 5 and 14 freeways. Interstate 5 travels from Mexico to Canada and is heavily used–about 10 lanes going though our town. The 14 is less traveled and only about 6 lanes wide.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

Coriolis Effect and Atmospheric Circulation Lab

I love it when I hear kids say “whoa”, or “wow” or “ohhhh, now I get it” during a lab. I recently did the “Coriolis Effect and Atmospheric Circulation” Carolina Investigations Lab for AP® Environmental Science and these were the reactions from students. It was a successful lab with good student directions and questions. The lab took about 45 minutes.

Teachers’ manual with my notes and hints for next year.

Students have a difficult time with atmospheric concepts and this lab helps students understand convection cells, coriolis effect, and how winds are created. There are a few hints that I learned along the way which I described below.


The kit is a little pricey, but the materials will last for year. It comes with supplies for 8 groups of students. I have 9 groups and it was easy to source the extra supplies from Amazon (click the item for the link to buy). I needed one additional turntable (lazy susan) which was inexpensive, one more overhead marker, another pie pan, and one more blow up globe. For next year, however, I am going to have 1-2 extra globes to spare as one got a hole in it first period and a couple extra pie pans they often get leaks as well. The kit comes with white globes–which are better, but harder to find spares. My extra globe wasn’t white, but it worked fine.

Supplies needed for each group of students.

You also need some basic lab supplies: two 100ml beakers per group, food coloring, ice and warm water. I used an electric kettle to heat up water for labs. One small pack of ice from the grocery store was enough for 5 classes–45 groups of kids.


The lab comes with a 4 page reading that is rather difficult text for students. Instead, I did atmospheric science drawing notes with my students one day before the lab. They used these notes to help them with the pre-lab questions.

I only made copies of the Pre-lab questions and lab questions for students. I did not use the reading/non-fiction text and made a class set of the procedure (called “guided activity”) to save paper.


Students begin by using the turntable to try to draw straight lines while another student turns the turntable. I had to show kids an example of what their circle paper should look like at the end, because I had kids making swirls as they didn’t read the directions carefully. I told them to keep moving the pen and try to draw a straight line.

Student sample.

Convection Fluid

Convection is difficult to show in the lab. This apparatus worked fairly well. Students were able to see the food coloring sink near the ice cold beaker and rise near the hot beaker. I had to tell kids to fill the beaker with as much ice as they could and I made the water very hot in the electric kettle. Kids also had to wait a few minutes for the food coloring to move which is difficult for them to do. I let them gently move the food coloring if they were behind other groups. The lab recommends putting the food coloring in the ice beaker for a while which is a good tip.

Ice beaker and hot beaker in a pan of room temp water from the tap. Convection shows up pretty well with food coloring.


In the last part of the lab, students use the turntable again with the globe. They map how the Coriolis Effect deflects air and creates winds using the marker on the globe. They did not fully understand what was happening until I had to tell them to think of the direction of the wind and it diverts to the right in the northern hemisphere. So looking down on the globe, the air traveling south from the north pole would divert right–which is to the west. But if you looked at the globe straight on, it appears to turn left. Once they viewed the air and globe in this way, they finally got it.

Using the blow up globe and turntable

For more AP Environmental Science Labs, go to this page.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

A Review of Pasco’s Wireless Sensors

I used some of Pasco’s wireless sensors in my classroom over the past two years in my high school science classes. Here’s my review of their wireless sensors with water quality testing and other applications. Pasco makes sensors and other technology for science and engineering and is a popular choice for technology in the lab.

Pasco Water Quality Sensors

Water quality testing is an important part of the curriculum of many science classes. My students test water quality not only in ecocolumns, but also when students bring water samples to class. I describe my water quality lab in this post.

SparkVue app on chromebooks gives the students immediate readings. It can also graph for change over time.

I tested Pasco’s wireless optical dissolved oxygen sensor, wireless pH sensor, wireless temperature sensor and wireless conductivity sensor in the aquatic chambers of our class ecocolumns. One of my student groups used the Pasco wireless sensors for three months of weekly data.

Pasco’s wireless pH, temperature and optical dissolved oxygen sensors

Students used Pasco’s SparkVue app for Chromebooks with the sensors. The app was easy to install on Chromebooks and easy for students to begin using. I created an instruction guide with screenshots for them. They did not need much help from me with these instructions as Pasco sensors are easy to use.

The Sensors

The optical dissolved oxygen sensor ($289) is a nice piece of lab equipment and does not need calibrating. It is waterproof–has a clear screw-on cap to keep the power button protected from water. This is nice if using in the field for a pond or stream. It also has a hook so you can lower with a string into a body of water. This sensor also has temperature so you don’t need to purchase a separate temperature sensor (but temperature sensors are very inexpensive and can be used for other labs).
The pH sensor ($65) was fairly easy to calibrate. I had to search for the calibration page online, however, as the directions did come with the sensor. I have buffer solutions of 4, 7 and 10 on hand and I only needed tow of the buffers for calibration. Calibration was easy to do on the SparkVue app.
The temperature sensor ($39) is straightforward and sturdy. The conductivity sensor ($95) is nice, because it shows total dissolved solids (TDS) as well as conductivity. This conversion from conductivity to TDS in Sparkvue is helpful for students so they don’t have to do the conversion themselves.

Powering and Connecting Pasco Sensors

Most of the sensors run on small watch batteries. This is a plus in that you don’t need to charge them, but can be a drawback as you will need to purchase batteries. Batteries last about a year with regular use. I keep a supply of batteries on hand from Amazon. I did have a lot of trouble opening up the battery compartment on one of the temperature sensors which is a downside as the plastic can sometimes warp/stick.

Most of Pasco’s sensors do not have a wire to connect to the computer. This can be a drawback if your computers don’t have enough bluetooth connections or if the bluetooth connections are not stable and its better to be wired. The Chromebooks I use currently have a lot of ports for each laptop and bluetooth wireless connectivity is not an issue.

Pasco Light Sensor

The light sensor ($69) is handy for a variety of uses. I used the sensor to gather data during the last eclipse, but lately, I’ve been using to measure light intensity of plant lights and light from my window. It’s been invaluable for me to understand how my fluorescent bulbs are holding up in my grow light units, how much light my plants actually get by the window, and how my new LED lights compare with older light sets.

Measuring the light in my grow light unit. The flourescent bulbs are 2 years old
The readings for my flourescent lights from the light sensor.
Measuring the light coming through the window in the afternoon.

Pasco Carbon Dioxide Sensor

The wireless carbon dioxide sensor ($195) has some nice features. Its design works well not only in the bottle that comes with it, but also in other empty bottles (like gatorade or vitamin water) that can be used for labs.
The sensor is also good for measuring decomposition in a bio bottle or the Pasco EcoZone System ($105). Waterproof plastic sleeves can be purchased to use to measure dissolved carbon dioxide which could be used when studying ocean acidification.

The wireless carbon dioxide sensor in the decomposition chamber of Pasco’s EcoZone.

For a review of Vernier’s wireless sensors, read this post.
For a review of Hanna’s wireless pH testers, read this post.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

A Review of Vernier Sensors

I recently tried a few of Vernier’s GoDirect Wireless Sensors with my high school students and liked many of their features. Vernier technology is a popular choice for many secondary science labs.

Water Quality testing with Vernier Sensors

I tested Vernier’s wireless temperature, pH, optical dissolved oxygen, conductivity, nitrate and ammonia sensors. One group of students used the Vernier sensors for their ecocolumn data and I also tested the sensors in my fish tank.

What I liked: Students were able to easily download the Vernier Chrome extension on their Chromebook: Vernier’s Graphical Analysis 4. I made detailed directions with screenshots for the students to follow. Students had no trouble connecting the Vernier sensors. Data was very quick and easy for students. The readings were a lot faster than some of my other probes.

From the top: Temperature, pH, optical dissolved oxygen, nitrate and ammonium sensors.

The optical dissolved oxygen sensor ($299) worked well and needed no calibration. The pH sensor ($89) needed calibration (as do most pH sensors and probes), but this was easy to do in Graphical Analysis. I have buffer solutions on hand, because I calibrate pH probes of varying brands almost weekly. The temperature sensor ($69) also worked well.

Vernier wireless sensors have to be charged periodically which can take some planning and a lot of plugs/ports for multiple sensors to charge. The sensors have a wired option so if the sensor is not charged, students can plug into the side of the Chromebooks. Our Chromebooks only have one plug-in port so students would have to use the sensors one at a time if not charged–but that’s typically fine for water quality testing.

Both the nitrate ($249) and ammonium ($249) sensors are harder to use. This is typical for this type of sensor of any brand. They need planning ahead of time. Both sensors need soaking in buffer solution for 30 minutes before using and often need calibration. However, I tested the sensors a week after calibrating and they held their calibration over the week of non-use. This is an improvement over sensors I used a decade ago.

Ammonium and Nitrate Sensors soaking in “high” calibration solution for 30 minutes.

Both the nitrate and ammonium sensors can inform how beneficial nitrifying bacteria are functioning. If a fish tank or aquatic chamber of an ecocolumn has low ammonia and higher nitrates, it means that there is a healthy population of bacteria for nitrification–the process of turning ammonium into nitrites and then nitrates. Ammonium is found in animal waste (like fish poop) and dead, decomposing organic matter. Ammonium is toxic to aquatic life in high amounts so a healthy population of bacteria is essential.

This fish tank has a healthy amount of bacteria as is shown by low ammonium and higher nitrates. The readings are shown in the Chromebook Extension: Graphical Analysis

Older Vernier Technology with New Sensors

I have some Vernier sensors from over a decade ago that use a TI-84 Calculator interface for readings. Many of the sensors still work, but pH sensors do not have as long of a life span. So, I recently purchased some new replacement pH sensors to plug into these calculators. I purchased the Tris-Compatable pH sensor ($99), because the bottom of this pH sensor is sturdier which is good for ecocolumns. Regular pH probes tend to be rather delicate on the bottom, but these can handle more bumps with gravel in the aquatic chambers of the ecocolumns. They can also be used to measure the pH of soil using a soil slurry. I was happy to see that I can still order Vernier sensors that work with the older technology .

Old TI-84 calculators with new pH probes.

For a review of Pasco wireless sensors, read this post.
For a review of Hanna wireless pH testers, read this post.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

Human Population 5E Lab Using Cemetery Data Part II

This post discusses each part of the 5E Lab. For suggestions, materials and set of the Cemetery Lab, read Part I.


In a 5E, an Engage should be quick and illicit prior knowledge. For this 5E, students answer these questions to get their brains thinking. This part only takes about 5 minutes for students to write and about a minute to share.

  1. Who is the oldest person alive that you personally know?
  2. Did anyone in your family live past 100? If so, who?
  3. How long do you think people live for? In other words, what’s the average lifespan of people in the United States?
  4. Recall survivorship curves. Describe the three types of survivorship curves.
    Type I:
    Type II:
    Type III:
  5. Which curve represents humans? _______
  6. Do you think human survivorship curves have changed in the past 200 years? How?


The “Explore” portion of the lab is not my own. It is taken from many shared cemetery lab resources from many generous teachers.

Students work in pairs and record their headstone data on Tables 1 and 2.

Next, they read the instructions and fill in their pair data in Tables 3 and 4–just the first column. You can copy one set of tables per pair, or save paper by putting the tables in plastic sleeves (or laminate) and use vis-a-vis markers and wipe off.

Students then enter their pair data (from Tables 3 and 4) on a class spreadsheet using Google Docs. I program the google doc to add the rows for them. After every pair has filled in the spreadsheet, Students use the class data to fill in # deaths, # survivors and % survivorship for Table 3 (Pre 1900) males. If using my spreadsheet linked above, make a copy of the spreadsheet as your “Master” and then make a copy for each period and erase the sample data inside. Also delete columns U and V with their formulas. Thank you to APES teacher Michelle Amos for help with the formulas!

After students calculate % survivorship by hand for the first spreadsheet (Table 3 Pre 1900 Males), copy and paste columns U and V from your “Master” into the spreadsheet. Student calculations by hand should match the computer generated ones.

To save time, I program the google sheet to do the other calculations for Table 3 females, Table 4 males and Table 4 females. I do not program the math calculations for the first spreadsheet, Table 3 males, because I want students to do the math themselves first to understand survivorship.

Students make a line graph with 4 lines on the same graph: Pre-1900 males, Pre-1900 Females, 1900+Males and 1900+ Females. Even though the computer can graph for them, I make students hand-graph so they understand not only how to graph, but can better understand the data.

There is a dramatic difference in survivorship for people born before 1900 and after 1900

Explain: Student-Sense-Making

In this part of a 5E, students begin to understand their data and make a claim at the end. Students may have some mis-conceptions and wrong ideas which is okay at this point. Walk around and read student claims to see where their thinking is at this point. Students will have the chance to correct their answers later so its not necessary to make sure they have the correct answers now.

Explain: New Understandings and Vocabulary

Now is the time to help students gain further understandings of population and introduce medical advances and diseases. I show this video on YouTube. Afterwards, students read this article “Ten Health Advances that Changed the World” and fill out this modified Frayer graphic organizer.

Next, students go back to their questions from sense-making and revise their answers.

Elaborate: Survivorship Curve Predictions and Demographic Transition

Students show deeper understanding by making predictions as to what would happen to a modern survivorship curve with various scenarios such as disease and pollution. By checking their predictive lines, you can see if they truly understand how survivorship changes. Students also connect survivorship curves with the demographic transition model.


This evaluate is optional. Students write a chunk paragraph describing how AND why the population dynamics of Los Angeles changed in the past 200 years using evidence from this lab.

For more population resources, I have two items on TPT: Population Math Packet with formulas, 3 practice worksheets, practice quiz, quiz with FRQ and answer keys. Also, Draw an Age-Structure Diagram (Population Pyramid).

For more labs per unit in AP® Environmental Science, click on this link.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

Human Population 5E Lab Using Cemetery Data Part I

One of the most interesting labs in Regular or AP®Environmental Science is using cemetery data for human population studies. This 5E covers Several topics from the new AP Environmental Science Course and Exam Description including 3.3 “Survivorship Curves,” 3.8 “Human Population Dynamics” and 3.9 “Demographic Transition” and 8.15 “Pathogens and Infectious Disease”.

The Cemetery Lab is also good for AP Science Practices of data analysis, math calculations, and text analysis as well as NGSS Science and Engineering Practices.

The lab takes 2-3 class periods (45-50 min) with homework.

For copies of all the Cemetery 5E Lab files, scroll down to “Materials and Supplies”

Different Ways to do the Cemetery Lab

  1. Go to a real cemetery with students
  2. Take pictures at a cemetery and use the pictures in lab (shown above)
  3. Use “made-up” tombstones from a file and post around the room
  4. Use a database of tombstone data from a real cemetery
This short video was taken when my students did the cemetery lab.

Cemetery Lab Pictures or Databases

What you choose depends on your resources. If you cannot take kids to a real cemetery, I highly recommend going to a local old cemetery and taking pictures of headstones, printing them and have students use for data in the lab. I live in a fairly new town that doesn’t have an old cemetery so my pictures come from nearby Los Angeles which is as local as I can get for my students.

Packs of 25 Pictures. My students work in pairs.

You need 200-400 pictures of headstones with enough pictures of the following:

  • Males and Females born before 1900 and after 1900 (about half and half if you can)
  • Women who died young-in their 20s and 30s (most before 1900)
  • Babies and young children that died (most before 1900)

My pictures are printed from Shutterfly as it was cheaper than color ink on my printer and they will last longer. But, you can always print on regular paper or have students use a digital file of the pictures. I have a pack of 25 pictures for each pair of students (18 pairs per class). Each period of APES analyzes 450 pictures. You can adjust these numbers as needed for smaller classes or less pictures.

LOCAL is always best for student learning, but if that’s not feasible, you can use this is a file of about 200 pictures of tombstones taken by AP® Environmental Science Teacher Eduardo Fernandez and shared with permission. These are from a cemetery in the Los Angeles area.

Another option is to print this file of fake tombstones made by AP® Environmental Science teacher Michelle Miller Fagen and post around the room, lab, hallway or other location.

Another option is to use an online database of burials in a cemetery. Find a Grave is one site that does this.

I do not have advice for going to a real cemetery as I have never taken students to one.

Materials and Set up for the Cemetery Lab

Materials for Day 1 of the lab (about 50 minutes)

These four papers can be laminated or inserted into plastic sleeves as they are not necessary for the students to keep. They are used for calculations that then go onto a class spreadsheet.

For Day 2 of the lab (about 45-50 minutes), student need:

  • Access to the class spreadsheet
  • A graph handout

Students can finish the graph at home as needed. I also assigned “Explain: Student Sense-Making” on page 2 for homework.

Day 3 of the lab (50 minutes) is best done in class to avoid students copying from each other, but this can also be given as homework.

The remainder of the lab “Elaborate” and “Evaluate” are easily done as homework.


Decorating the lab is really fun if you do the lab in the month of October for Halloween. I have Halloween lights, fake cobwebs, and play spooky classical music.

My lab/classroom with Halloween decoration. The back wall has a lighted spiderweb.

My students use their cell phone flashlights to do the lab which makes it more fun. Some even make a lantern with their phones and a beaker of water.

Go to the next post for details about each part of this 5E Cemetery Lab.
Human Population 5E Lab Using Cemetery Data Part II

For more population resources, I have two items on TPT: Population Math Packet with formulas, 3 practice worksheets, practice quiz, quiz with FRQ and answer keys. Also, Draw an Age-Structure Diagram (Population Pyramid).

For more labs per unit in AP® Environmental Science, click on this link.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

Tree Rings and Climate Lab

Tree rings are a good way to study past and present climate. They are proxy indicators of climate change, but can be used to study other climate events as well. You will need several handouts for this lab. The student handout is on this google doc. Note: There are a lot of regional-specific questions in this lab. You will need edit for your own tree cookies and region.

You also need the document “Reading the Rings of a Tree” as a student reference sheet.

You can use large or small tree cookies, but larger ones typically have more interesting data and weather, insect or fire events.

Finding Tree Cookies

  1. You can purchase tree cookies on Amazon or Etsy. Its easier to buy them, but kids get more out of the lab if you can find local tree cookies.
  2. Wood-shop or career-tech construction classes. We have wood-shop on campus and the teacher had a spare log and cut a bunch of tree cookies for me. Shout out to Leonard Friedman, woodshop teacher extraordinaire!
  3. Find or buy a log and use a chainsaw to cut your own cookies.
  4. Wait until after Christmas and use a discarded live (now dead) tree.
  5. Ask a tree-trimming company for branches or trunks of trees they are removing.
  6. A firewood company may sell you unsplit logs.
  7. A local college or extension may have some tree cookies to loan.
These tree cookies are from a local pine and show evidence of insect infestation.

Other Supplies

Setting up the Lab

Prepare tree cookies by placing pins on some of the dark rings. This helps students identify and measure between rings. Reading rings is actually harder than it seems. Students (and teachers) have some difficulty with this. When they are counting the number of rings, tell them to ESTIMATE and do the best they can, because its difficult.

If you have hard wood, you may need to use a hammer and thumb tack to make hole before then putting in one of the other pins.
Customize your pins based on your location. This tree cookie shows severe drought in CA in the pink, black and blue pins and some El Nino years earlier.

If you choose to protect the trees with varnish, I recommend flat varnish, because gloss or semi-gloss reflect overhead classroom lights and make counting more difficult (learned this the hard way)

Copy the paper tree cores on card stock or laminate for durability. That way you can use for multiple periods and multiple years.

Measuring a paper tree core.

Preserving Tree Cookies

If you want to preserve your tree cookies to use for a long time and also prevent bugs and pests, the following are directions from APES teacher Mark Case:  “I make tree cookies regularly. Step 1: soak the cookie in antifreeze for about a week. Make sure it is very well penetrated. Eggs and larva die. Step 2: Freeze for 72 hours in a deep freeze. Step 3: use a solar dryer. Any type tote and a piece of glass or plexi glass over the top in the hot summer sun. Step 4 let it dry for at least a week before you coat it with poly. “

AP® is a trademark registered and/or owned by College Board, which was not involved in the production of, and does not endorse this site.

Airborne Particulates Lab Using LED Tap Lights

I recently experimented using LED tap lights as an alternate to using stereoscopes in the Airborne Particulate Lab. You can read about the lab on this post. This is a great lab for kids to practice experimental design.

I purchased LED tap lights from Amazon but they can also be found at home improvement stores.

They work with a little finesse. Here is what the kids need to use:

Students need to focus on the vaseline above the grid. If they focus on the graph paper, they won’t see any particulates. They need to hold the hand lens about 3-4 centimeters above the petri dish. That way it focuses on the particulates.

This method does work, but it takes a little more practice from the kids to see the particulates.

Toxins 5E Lab

Two important topics in APES are combined for this 5E–Serial dilution Lab and LC50 Lab. The lab papers needed for this lab can be found on these google doc links.
Engage, Explore, Explain
Elaborate, Evaluate
How Toxic is Toxic
LD50 of Substances

Engage: Flint, Michigan

This Engage is a short case study about lead exposure for students. Most students have heard of Flint, Michigan and its water quality problems so this adds to previous knowledge (a key component of Engage). The video piques their interest and then we discuss our own drinking water and how this problem would not occur here, because we are a newer community that does not have lead pipes. We also discuss how older cities with lead pipes can prevent lead leaching by using an additive in the water. Click to read this article explaining more about how lead gets into drinking water.

Explore: Serial Dilution

Students in AP® Environmental Science need to understand how toxins can still be prevalent in very small amounts. The best way to do this is for students to do a serial dilution. (Note: This activity is courtesy of Dan Hyke from the APSI, I attended in 2006. I have altered it and combined with LD-50 for this 5E)

Materials needed for serial dilution

As students walk through the procedure, fill in their data charts and answer the guiding questions, they hopefully will come up with the concept on their own–toxins can still be present even in very small amounts such as parts per million (ppm), parts per billion (ppb) and parts per trillion (ppt). Materials needed are: (Click on an underlined item for a link to the product)

  • Well plate
  • Plastic Pipet
  • Beaker for tap water
  • Toothpicks
  • Dropper bottle of a dye/stain/coloring such as a Food Grade Dye like FD&C Red Dye #40 Do not use regular food coloring as it dilutes much too quickly

Students use 3-4 drops of the red dye solution in the first well.  Then they fill the other wells with 9 drops of tap water. After that, they drop one drop from the previous well and stir.

Well Tray at the end of the lab

Students are often concerned when their solution is clear by well 7. I tell them that’s normal and they are to still make the transfers. They need to move the molecules in order to understand the point of the lab.

Students creatively identify shades of red and pink and learn about ppm, ppb, and ppt on their data sheet. Some students will need help with these circles. I tell them that “their brains will hurt” today.

Sample serial dilution data
Students using an online thesaurus to get creative on shades of red

Explain: Student Sense-Making

In a good 5E, students should be able to develop the concept you want them to on their own. Developing good guiding questions is your job as the teacher to lead them to it.  For this lab, students should make a CLAIM or a STATEMENT that “Substances can be in water even if you cannot see it, smell it or taste it.

Elaborate: LC50 Lab

We use the results from the salinization Lab to do LC-50. Students bring their salinization labs back to class and we collect class data. (Students save all work in their APES binder) This time, however, we want “opposite” data–the number of seeds that DIED, instead of the number that germinated.

Students fill in the chart for their group’s data and then all students copy class data. I often make a chart on the board for groups to fill in.

From there, using a document camera or on the board, teach students how to find the LC-50 by drawing a line from 50% on the y axis to where it hits the dose-response curve and then down to the x axis. Read the concentration that kills 50% of seeds. If you need help with this, I made this video for absent kids that may help you understand how to do this lab:


This 5E does not have its own Evaluate–rather students are assessed for these skills and knowledge on their next exam.

* AP® is a trademark registered and/or owned by the College Board which was not involved in the production of, and does not endorse this site.

Trees, Forestry and Deforestation 5E

Take students outside to measure trees, discover ecosystem services of trees and forests, develop math skills, deforestation and sustainable forestry in the “I Love Trees 5E” Lab. If you are lucky enough to teach at a school next to a forested area, take the kids there. If not, trees on the school grounds, park or other area work just as well.

Student using a homemade clinometer to measure the height of a tree at school

Teacher Preparation

For this 5E, you need to make clinometers using cardboard, string/yard, a piece of metal (anything with a little weight) and a straw. You can have students make the clinometers if you would like, but I had my student lab assistant make 10 clinometers for me to save class time. They can be reused over and over. I made one clinometer for each group of 4 students.

Class set of clinometers that can be reused over and over

You also need two sewing tape-measures for each group of students and a tree map. I identified the trees ahead of time in the study area and googled their density. You could teach students how to identify trees using the iNaturalist app or a field guide if you want.

Materials for 1 group of students. One clinometer, two tape measures, and a tree map of the school grounds


An engage section of a 5E should be very short. For this 5E, I asked kids about the biggest tree they’ve ever seen. I find that personal questions where kids can share with their elbow partner and the rest of the class is very engaging. Another part of the Engage sections is review the photosynthesis equation–a good 5E builds on previous knowledge.

I show my own pictures with large trees (like Sequoias or Redwoods at the National Parks or large oak trees in town). Students like to see their teacher’s pictures.

This picture was taken 10 years ago in Sequoia National Park. My children are now older and one is in my APES class. Kids LOVE to see this.

Explore #1

Students head outside to take data in this Explore. Its helpful to demonstrate how to use the clinometer before heading outside. You or your students will choose a tree and measure the tree height using a homemade clinometer. They will also measure the tree circumference using the measuring tapes, the distance the tree to a building and the condition of the tree. After measurements, students will do math calculations using given formulas to help them determine the height, diameter, volume and mass (using the density), and the carbon sequestered by the tree.

Students hold the clinometer with the plumb line straight down and then walk forward or backwards until they can see through the straw to the top of the tree.
Students measure the circumference of the tree using measuring tapes and then use a formula to find the diameter.
Students use two measuring tapes to measure the distance from the tree to the student using the clinometer. The easiest way to do this is to “leapfrog” two tapes as shown above.

Explore #2

Students head back to class to enter their tree’s data on iTreeTools. 
Data chart for the results from iTree is below:

Total benefits for this year $
Carbon Dioxide Sequestered $
Annual CO2 equivalent of carbon kg
Storm Water runoff avoided $
Air Pollution Removed each year $
Carbon monoxide removed g
Ozone removed g
Nitrogen Dioxide removed g
Sulfur dioxide removed g
Particulate matter < 2.5 microns removed g
CO2 Stored to date $
Life CO2 equivalent of carbon kg

Explain: Student-Sense-Making

Students work through a series of questions to help them discover the scientific concept on their own. Sample questions:

  1. What are the $ benefits of your tree? _________________
  2. Review: What is the photosynthesis equation:
  3. Draw a picture of the tree and show how molecules are moving
  4. Where does the C from CO2 end up?
  5. Think about it: How does cutting down trees for lumber and paper affect atmospheric carbon?
  6. Think about it: How does cutting down trees and burning them affect atmospheric carbon?
  7. Many species of trees increase in density, as they get older. How does this affect carbon sequestration? (Hint, the mass increases also).
Sample drawing for #3 above. The idea is for students to understand that carbon creates biomass in trees and other producers.

These and other questions help students discover the scientific concept/s and make a CLAIM. This is the place for formative assessment. Walk around and check student claims. Make sure they understand what you want them to understand.

Question :: How can how trees provide ecosystem services regarding climate
change, air pollution and water pollution:
Claim :: (Complete sentence answer to the question above.—Make sure you write
about ALL THREE ecosystem services)    

Explain: New Understandings and Vocabulary

This is the place for formal science instruction. in this E, students will watch a series of 3 mini videos that describe more ecosystem services of trees and why tree-sitters do what they do. Students record more ecosystem services of trees on their lab report. Its best to do this portion as a class so that you can stop and discuss. However, it can be done at home, if needed, to save time. One video is a lovely TedTalk about trees.


In this section, students learn about deforestation and then sustainable forest solutions. Students will watch a series of 6 mini videos and fill in a T-chart with facts about deforestation and facts about sustainable forestry. Two sample videos are:

While there are some counter-arguments to sustainable forestry, students need to understand some solutions for exams. You can discuss places you agree or disagree with sustainable forestry.


The evaluate section of this 5E is unique, engaging and fairly easy to grade. Students will fill in the branches of the tree drawing with 5 ecosystem services:

Students then describe problems with deforestation next to the stump:

And methods of sustainable forestry next to this drawing:

The Evaluate section can be done individually or with a partner–with or without notes. You decide which is best for your students.

Open Access Picture credits: