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)

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.

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.

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:

Evaluate

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.

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.

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.

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.

Engage

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.

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.

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).

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.

Elaborate

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.

Evaluate

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: https://commons.wikimedia.org/wiki/File:Stubb.jpg
http://www.ca-ilg.org/post/sustainable-forests
http://clipart-library.com/clipart/pc58xpdni.htm

The Theory of Island Biogeography is a nice 5E lab using inexpensive materials (funnels, beans and poster paper) that not only teaches students an important concept, but also helps develop higher level thinking skills.

The Theory of Island Biogeography states that larger islands closer to the mainland have higher biodiversity than smaller islands further from the mainland. This theory is also applied to isolated habitats on land. You can read about this concept on this document and can share with students.

The basic concept of this lab is not complicated for students, but applying it to preserving biodiversity on continents or even thier own community can be counter-intuitive. Students have difficulty realizing that we have isolated habitats on land and that preserving pockets of habitat that are larger and closer together is the best for biodiversity.

The 5E Lab

This Island Biogeography Theory 5E Lab is inquiry-based to help students discover the concept on their own and develop critical thinking skills to make real-life applications.
Engage: Students discuss how animals or plants migrate to islands.
Explore: Students drop beans through funnels onto a poster multiple times and count the species that land on each island. They do some math to help them calculate averages per island.

Explain: Students make sense of their data using guiding questions and make a claim about the scientific concept–this is a great place for formative assessment. Then, they read a passage explaining the theory in formal academic and scientific vocabulary.
Elaborate: Students apply this knowledge to isolated pockets of land in their community using Google Earth–its best to do this as a whole class so that you can help students find pockets of habitat. This is something that most students have never realized, but when they do, its a great “aha” moment.
They then apply this knowledge to our National Parks. Using a map of the National Parks, they are asked which parks would have the most biodiversity using this theory and then where they would create a new park. Many students want to put a new park in a state (like Kansas) that doesn’t have any national parks. This is incorrect according to this theory. A large park next to an existing large park is the best solution according to this theory.

Evaluate:  Students write a chunk paragraph addressing the following questions. They are to base their argument using evidence from this lab.

• What do you observe in your town about habitat fragmentation?  What kind of wildlife would be the most affected?
• How could we use this concept when we develop urban planning? How should development occur to preserve the most species?

The labs on this post tend to be popular, because they cover a lot of topics within the lab, build skills, and/or are engaging. You don’t need to do all of them! I do about half of the ones listed below. Some labs have links for the write-ups.

Read APES Lab Supplies Part 1 for Must-Do Labs

APES Lab Supplies for Popular Labs

• Ecocolumns
  • This is a favorite lab for kids and gives them long-term data collection and analysis. Click for the supplies for this lab. I have recommendations for cheap and more expensive supplies depending on your budget.

• Tragedy of the Commons:  This lab has many great versions.
  • Colored marshmallows, goldfish crackers, or candy are favorites. Some teachers use beads to be reusable. If you have large classes, marshmallows are the cheapest.
  • Straws or chopsticks
  • Tape
  • Paper plates or paper towels

• Owl Pellets
  • Large (preferred) or small owl pellets. One per pair or group.
  • Gloves
  • Dissection trays or paper plates
  • Tweezers
  • Reference sheets

• Biodiversity:  There are many varieties of this lab that are used including:
  • Parking lot biodiversity lab
    • Needs no supplies
  • Biodiversity of plants using quadrats
    • Can make sampling squares, or use pieces of string or buy collapsible hoola hoops
  • Tree biodiversity in forests (if you live by a forest).
    • Need tree ID reference sheets

• Island Biogeography
  • Many versions. Some use beans and funnels and meter sticks
  • Others use birdseed, paper clips, cotton balls, beads etc to throw at paper islands.
• Toxins (Serial Dilultion and LD-50)
  • 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
• Trees, Forests and Deforestation 
  • Cardboard box
  • Straws-can be paper straws or other eco-friendly straw
  • 2 sewing measuring tapes per group

• Ocean Acidification
  • Plastic cups: 4-5 per group
  • Shells (ask kids to donate or ask seafood restaurants for oyster, clams and mussel shells). One small shell or piece of a larger shell per group.
  • Vinegar or another acid
  • pH meters or pH strips
  • Scales-pocket or regular
  • Plastic pipets

• Cemetery Lab for human population studies
  • No supplies needed if you can walk to an old cemetery
  • Or, pictures of tombstones taken from a local cemetery
  • Or, simulate using paper tombstones in lab, you may want to decorate the lab with Halloween decorations. The dollar store is a good source.
  • Or, use a cemetery database
• Oil Spill Cleanup
  • Plastic containers or metal pans to hold water and simulate the ocean. One per group.
  • Cotton Balls
  • Straws
  • Plastic pipets
  • Cups or Beakers
  • Vegetable or mineral oil
  • Detergent
• Air Pollution Labs.  There are a few good ones to choose from.
  • Air Pollution Kit
  • Ozone Lab using Test Strips 
  • Design a scrubber kit
  • Air Particulates Experimental Design Lab
    • Petri dishes-2 per student, if possible
    • Vaseline
    • Tape-blue painter’s tape is best as it can be removed easily to allow reuse of the dishes.
    • Stereoscopes are best. Microscopes can also work using a low objective. Hand lens with a good light source work, but are more difficult for kids to use. A good light source is LED touch lights.
    • Poster paper with markers (optional) for lab assessment

• Biomagnification Activity: Many great versions of the lap exist
  • One version of the lab uses colored paperclips
  • Another version uses pieces of laminated paper (shown below)
  • Another version uses candy

• Kill-A-Watt Lab
  • Need several kill-a-watt meters. I use 10 of them for kids to rotate stations
  • You also need various electronic devices.

• Productivity–there are many versions of this lab also.
  • One lab uses grass seeds, potting soil and pots
  • Another lab uses bottles of water with algae and dissolved oxygen probes
  • I do a video virtual lab
  • You can also purchase a kit. 
• Soil Profiles made out of food items
  • Plastic parfait cups: one per student
  • Vanilla and chocolate pudding: quantity depends on number of students.
  • Oreo cookies
  • Sprinkles
  • Gummy worms: 2 per student
  • Spoons
• Climate Change and Cities Experimental  Design  Lab
  • IR Temperature guns OR regular thermometers/sensors
• Cookie Mining
  • Generic chocolate chip cookies (1 per pair of students)
  • Name-brand chocolate chip cookies
  • Extra cookies to eat when finished
  • Paper clips
  • Toothpicks
  • Scales-pocket or regular (optional)
• Solar Cookers (usually done after the AP® exam due to time requirements)
  • Aluminum foil–a big restaurant-sized roll from Costco or Amazon will make a lot of solar cookers (40-50 of them)
  • Packing tape or duct tape
  • Masking tape
  • Lots of boxes: I ask the food service on campus for empty boxes
  • Empty cans to test water temperature
  • Plastic wrap
  • Thermometers
  • IR Temperature guns (optional)

• Biological Oxygen Demand (sometimes done with a water quality lab)
  • I do as a virtual lab
  • If you do as a regular lab, you will need a dissolved oxygen test kit or dissolved oxygen probes
• Tree Ring Studies for climate change
  • Need various “tree cookies” (tree slices) 
  • Or, use a kit that simulates tree cores
• Trees and Forests 5E
  • tape measures
  • Homemade (I use the homemade ones) or purchased clinometers
• Chalk Drawing:   The best chalk is from IKEA–seriously. A few boxes will last the entire year or more. Since I teach 170 students in APES, this is the best option for me. Neon Expo Markers are another good option.

Other Basic Supplies

I use these items frequently for many labs

Sharpies (need 10 black for the year)
Spoons (need 1 box for labs)
De-chlorine drops for fish tanks
Filters for fish tank
Aquarium light bulbs
Fish food
Colored markers (Crayola or similar) for lab conclusion posters
Painter’s tape for marking beakers, lab apparatus
Hand Sanitizer-large container for classroom
Batteries for various sensors and probes

A question new AP® Environmental Science teachers ask is “What supplies do I need?” or “What kits should I buy?” This post will go over basic APES lab supplies.

Kits are a great way to start and can help many new AP® teachers, but aren’t necessary if you don’t have the funds. Most labs can be sourced more cheaply by ordering individual items.

APES lab supplies can be cheap or expensive.  What you decide to do depends on your location (some outdoor labs are regional), the materials you have, the size of your classes and how much money you have.  Over time, apply for grants and other funding to build up your supply of plant lights, probesware etc.

You need basic lab supplies that your school should already have such as glass and plastic beakers, balances, graduated cylinders etc.

APES Lab Supplies for Must-do Labs

While there are no official required labs for APES, there are a few which have appeared on the AP® Exam or cover many concepts that have appeared on the exam. Here are some recommendations for APES lab supplies.

• Salinization Lab:  For this lab you need
  • Salt
  • Petri dishes or ziploc bags
  • Distilled water
  • Plastic pipets
  • Seeds.  Peas, Mung Beans, and Radish are all good options

• LD-50 Lab: You can do this lab many ways.
  • Use salinization lab results so you aren’t taking time for a new lab.
  • Purchase a kit.
  • Purchase individual supplies for the lab
    • Macroinvertebrates such as brine shrimp or daphnia, or seeds
    • Some kind of toxin
    • Beakers/cups etc.

• Soil Quality Labs. There are two main soil labs that are essential:
  • Chemistry of Soil
    • Use a Test Kit  (best) or a soil meter.
    • Alternately, You can also take soil measurements with the ecocolumn lab instead of doing the chemistry of soil lab.
  • Physical Properties of Soil.
    • Can be purchased in a kit
    • Or individually purchasing materials such as sand, soil, gravel and plastic cups.

• Water Quality Lab
  This is an expensive, but essential lab. You can do this lab several ways:
  • An inexpensive kit for the lab
  • If you have a pond or creek to walk to, you may want a portable kit and a couple of hip waders and macroinvertebrate collection devices or kits.
  • Probes or sensors are more expensive initially, but end up saving money over multiple years. See this post for supply ideas for an in-class lab.
  • My favorite inexpensive dissolved oxygen meter is the Milwaukee Dissolved Oxygen Probe.  It rarely needs calibration and lasts for years. Also, fairly inexpensive (for a DO meter) on Amazon.

• Experimental Design Lab:  Don’t do as a separate lab just to teach scientific method at the beginning of the year–you don’t have time in an AP® course. Instead, teach experimental design with another lab such as salinization,  ocean acidification, biodiversity with quadrats, or air particulates.

Read the next post for more recommended labs.

APES Lab Supplies Part 2: More Recommended Labs

One of the best (and easy to implement) labs I do is an air pollution lab–airborne particulates lab. I worked with a colleague at a neighboring school (Laura Solarez) to develop this lab for AP® Environmental Science.

This is an experimental design lab which is really important for students to do at least once or twice in the year, because the AP® Exam WILL have experimental design questions on the multiple choice section and sometimes on an FRQ. The AP® exam will ask complicated higher-level thinking questions-many of which are experimental design. 

Materials

Materials are quick and easy for this lab

1. Petri dishes-2 per student, if possible
2. Vaseline
3. Tape-blue painter’s tape is best as it can be removed easily to allow reuse of the dishes.
4. Stereoscopes are best. Microscopes can also work using a low objective. Hand lens with a good light source work, but are more difficult for kids to use. Read this post for using LED tap lights.
5. Poster paper with markers (optional) for lab assessment

Day 1

Day one of the air pollution lab takes about 45-60 minutes. Student lab groups brainstorm and come up with a question to test, a hypothesis, and design. They must get two approvals from me before making their petri dishes.  My students have already done an experimental design lab so this process is fairly quick at this point. If this is the first experimental design lab of the year, expect this to take longer and for students to need more revision.

This lab is challenging with the constants. They can never really isolate all the variables and because of this, they will get flawed data. This is really important!!   Analyzing the weaknesses in their lab help them identify flawed experiments later on in life and on the AP® Exam. I aim to develop scientifically literature citizens.

I give students some ideas such as comparing indoor vs. outdoor particulates, front yard vs. back yard or the number of pets. Some students come up with very creative ideas outside of these suggestions.

If rain is in the forecast, make sure they don’t set out the dishes in the rain (or sprinklers). Also, they need to make sure they all set out the dishes on the same day for the same amount of time, because weather can influence.

After approvals, students make their dishes. I made this video last year. They pay attention to the video more than me demonstrating in person!  I show the video up to minute 3:18 on Day 1

Make sure you tell students to make a little sign at home, because I’ve had many dishes thrown away by parents over the years. They don’t know what it is and just throw away. Students make a sign that says “Science experiment–don’t throw away”.

Day 2 of the Lab

Day 2 of the air pollution lab is several days later. Give students enough time (over the weekend, for example) to expose their dishes for at least 24 hours. Students bring their dishes back to school on the day you instruct.

I show the rest of my video to help them understand how to count the particulates using stereoscopes. If you don’t have stereoscopes, you can use LED tap lights and hand lens.

Students need to make a template out of graph paper to use on each petri dish. Its impossible to count every particulate so using a template with a few boxes helps them manage the counting.

Since students work in groups of 4, they divide up tasks. Some count data and some begin their posters. They can switch jobs if they desire.

After students finish counting particulates, They can wash the dishes in hot soapy water and dry. The dishes can be used again next year and also for the Soil Salinization lab.

Assessment

I like students to make and present posters for this air pollution lab. It really helps them discuss and analyze the results. Why their hypothesis was correct or not AND more importantly, why this lab was flawed. They can never fully control all the variables and I want them to see that other factors may have influenced their results. This is the best part of the lab–learning to identify flawed experiments.

My poster template is inspired by Argument-Based Inquiry, but I have added more sections and clearer instructions.

I have had students present to the entire class, present to two other groups, or make a Flipgrid. All three ways have merit.

You can also have students write a formal lab report individual or as a group as assessment as well.

Click for a poster rubric.

A complimentary lab is the Kill-A-Watt Lab.  A lot of particulates air pollution comes from the production of electricity from coal. This lab also helps students develop math skills.

Water Quality Testing is essential for AP® Environmental Science students. Every released exam has water quality test questions.

Ideally, taking kids to a stream or pond is best, but testing water quality in the field is not possible for my students in arid Southern California.  Surface water is seasonal and often too far away.  Instead, my students bring in water samples to the lab.

Scroll to the bottom for links to student handouts.

Teaching Students to Collect a Water Sample

I demonstrate how to take a water sample for students.  This year, I made a video which they enjoyed more than my demonstration.

Any empty bottle (water, Gatorade etc) works. Rinse out a little with the sample water and then fill under the water.  Interesting water sources include rivers, creeks, ponds, lakes, well water, the ocean and fountains.

Ideally, students should wear gloves to collect the sample. But, if they forgot to bring gloves, they can throughly wash with warm water and soap after collecting the sample.

Students should cap the bottle under the water to prevent air at the top from skewing the dissolved oxygen (DO) results.  Sometimes, this isn’t possible (with a small creek or heavy waves in the ocean) so I tell them to do the best they can.  There is some error as Biological Oxygen Demand will decrease the DO reading, but we discuss this.

Students need to label the bottles and bring to class on the day we do water quality testing.

In the Lab

I used a LaMotte water quality testing kit the first year I taught APES, but soon realized that probeware was more economical in the long run with the quantity of students I have.  I was accepted for grant funding to purchase my initial probeware and have used science funds and donation money to replace items as needed. Read where to find science funding.

 

I use a variety of water quality testing devices that are easy to use. I used to have a full set of Vernier probes, but over time they either broke or I stopped using them due to needing calibration–sometimes right in the middle of a lab! This collection is what I currently use–requires little prep work on my part and works for an entire day–5 sections of APES students.

I rotate baskets instead of kids going to stations. This is easier with 36 kids in lab and then they don’t have to travel with their water sample.  I give kids about 4 minutes per basket and then they rotate clockwise. Kids also spend that time using reference sheets to see what the test measures and what are the levels for safe drinking water and for healthy aquatic life.

Water Quality Testing Devices

This is the LaMotte Testing kit I used before I received grant money to purchase my initial probeware 12 year ago.

Today, I use a variety of items that are reliable, economical for 165 kids in APES and easy to use. They’ve been acquired over a dozen years through various means and I’ve changed a few items over time. Most of them have links to Amazon if you want to read more about the item.

Fecal Coliform Bacteria is also very important, but also very expensive. If you have the funds, its great for kids to do in lab.  If not, make sure they learn about it.  This year, I made an instructional video instead of purchasing $100 worth of tests.  

In years past, I have purchased Coliscan Easy Gel which works well and is easy to use.  I’ve also used Petrifilm which is a little more economical for large classes. 

Students also record odor and color, but those are observations.

Resources

Click for my water quality lab handout for students.  You will need to change the handout to match the items you have for testing. Also, there is a link for our local water quality reports. Find your own local report and change the link.

These are my reference sheets. Again, you will need to add or subtract for the tests and devices you have.

Have fun water testing!

 

One of the most common (and important!) labs in AP® Environmental Science is the Soil Salinization Lab.

There are many versions of the lab that are great. This is mine.  It has been altered and changed with ideas from lots of teachers over the year.

(Side note:  I am a HUGE fan of inquiry, but I do not do an inquiry lab for this topic for a couple of reasons.  I want kids to do a proper controlled experiment before they do experimental design later on. They can refer to this lab when they are designing their own later in the year. This is part of scaffolding. With each controlled experiment (such as Ocean Acidification), I remove more instructions and parameters. Another reason is that I also want the kids to test specific concentrations of salt, because we use the results for an LD-50 lab later in the year.)

Materials

1. Seeds
2. Graduated cylinders with optional pipets to help kids with precise measurements. Mark one graduated cylinder for the 5% solution and one for the distilled water. Same with pipets. This prevents cross-contamination. Train the kids to be careful and prevent cross-contamination. Even a couple of drops of salt left over in a graduated cylinder can influence results.
3. Overhead markers
4. Scissors to cut paper towels
5. 5% salt solution (mix yourself)
6. Distilled water
7. Beakers
8. Petri dishes or ziploc bags. Petri dishes can be reused for an air pollution lab-Airborne Particulates.

Prepare a 5% salt solution by mixing 5g of NaCl (Table salt) with 95ml distilled water. Make enough for your classes.  I make about a liter for my 5 classes of APES.

I like pea seeds and prepare these containers for the groups. Tell the kids to keep covered to prevent fungi contamination. Fungi does ruin the soil salinization lab on occasion. I’ve had it happen once in 12 years. Use very clean petri dishes and keep beakers covered when not in use to prevent this.

What seeds to use?

I’ve used peas, mung beans and radishes for soil salinization over the years. My favorite is peas, but the others work as well. Radishes tend to have lower tolerance to salt. You can even have students test different seeds in different groups. Mung beans sprout quickly and have a nice tolerance to salt as well.

Using Ziploc Bags

I use snack-sized Ziploc bags with my online APES class that I meet with on Saturday mornings a few times a year. The bags are convenient as I don’t need them back when the lab is over and they’re inexpensive.  In my regular classes, I prefer petri dishes as they can be reused from year to year and are easier for the kids to work with the seeds.

The write up using ziploc bags can be found here.  I also use a Flipgrid conclusion so they can film their results and show me at home.

Use a sharpie to mark the bags and create a paper towel “taco”. Wet the paper towels before putting the seeds in or they roll around too much.

Day 1 of the Lab

Go over the first page of the lab together with students.  They have difficulty with the terms (control, variables, constants) if they’re out of practice. Also, teach the students to use words such as “increasing” or “decreasing” in their hypothesis as this is good practice for FRQs.  Its also more of a “collegiate” and precise hypothesis.

Students need to do the math for serial dilution before beginning the lab. I usually go how to do the math and then they can easily solve.

After doing the math, they can prepare the soil salinization dishes.

Make sure they use separate graduated cylinders for 5% NaCl solution and distilled water. Have a “mixing” beaker to mix the solution before pouring over the seeds. This makes sure that the solution is evenly mixed.

Best way to prepare the dishes

Day 2 the lab (3-4 days later is optimal)

Students will take data on the # and % of seeds that germinated and measure the sprout length. I tell students to measure the longest sprout in each dish.

Results take about 15 minutes. Then students wash and dry dishes. I store and use the dishes again for an air pollution lab and again next year.

 

Updated Spring 2019!

This year, I revised my Kill-A-Watt lab with a lot more math, better leading questions to help students to figure out the concepts, a phenomena that is referenced throughout and an Evaluate with solutions. The lab with an answer key can be found here.

Students always need more math and so this updated version has more calculations based around different strands of Christmas Lights. It brings in the concept that cheaper devices break more often and have more economic consequences as well as being more expensive in the long run. 

The math is challenging for students. They needed some scaffolding and we worked through the first part of #17, 18 and 19 together.

I added an “Evaluate” section which has students find solutions to reducing energy. This is surprisingly tricky for students. The question asks them to find ways to REDUCE energy use. Kids automatically think solar and wind and electric cars. None of these reduce energy–just switches to a more sustainable form. Kids need to learn to answer the prompt carefully.

In addition, I added a video at the beginning to engage students as a short phenomena–admittedly its not a great phenomena in the idea NGSS way, but it is really engaging, makes students confused and helps bring together some difficult concepts. I refer to it several times throughout the lab. Note: It is a strange video and a little shocking for students. The link is on the answer key in the lab. Use your own discretion on whether to keep it or not. I found it effective to help students understand a lot of concepts about developing countries, tourism, energy etc.

Original Post

Recently, I received a grant for Kill-A-Watt meters and implemented this new lab.  It teaches students about electricity, watts, math and conservation using Kill-A-Watt meters. The kids were SUPER engaged (so were adults who came by) and it was highly relevant for not only their lives, but the energy concepts they need to know.  My AP® Environmental Science students did the lab, but the AP® Physics B teacher will also use this year.

Click for a copy of the lab.

You will need to alter the copy to reflect the cost of electricity in your town and the specific appliances that you have or want to use in lab.

Supplies Needed

• Kill-A-Watt Meters:  I had one meter per lab table with two items to test at each table.  I ordered the Kill-A-Watt EZ model from Amazon.  But, I also like the regular model too.   The EZ model lets kids see the cost of electricity more easily, but the regular model is easier to use and find the “watts”setting.  Either are fine for this lab. (But, if you use my write-up, be sure to change some of the instructions if using the regular model).

In order to afford 10 of them, I wrote a grant request on Donors Choose and was funded in a few days by two corporate sponsors.  Here is a post about my favorite ways to find funding for new labs. 

• Various appliances from your science room or from home.
• Power Strips (optional).  The plugs in my lab are on the sides of the tables so I found power strips were very helpful. That way all the kids in a group could see the meter when it was plugged in.  I ordered a few of these to have ready next year.  If your’e writing a grant, be sure to add a few of these, if needed in your lab.

  

• Christmas lights (optional, but really engaging for the kids) .  I was fortunate to find regular and Energy start Christmas lights at Target in October, but I couldn’t find LED lights so I ordered online.  They were pricey, but I only needed 1 strand and it will last for several years for this lab. (And I can use to decorate my classroom for Christmas!)

  

Lab Setup

I had two devices per lab table and meter.  The students rotated from table to table.  I utilized items in the lab whenever possible, like this TV.

Data-Explore section

Students took data on a chart and then created a graph.  I had a Kill-A-Watt meter set up at each lab table along with 2-3 appliances and then set a timer for kids to rotate every 4-5 minutes.  I had 9 tables and it took about 45 minutes to rotate to every table.

If kids finished that station before the timer, they worked on the bar graph of their data chart.

Explain-Vampire Power and Conservation

I showed a couple of videos helping explain some of the data that kids see.  I wanted them to notice the appliances that still drew power even when not turned on.  Many students have never heard of this.  I also wanted them to see good examples of energy conservation.

Elaborate–Math Calculations

Kids did A LOT of practice with energy math–which they need for the AP® Exam.  It is also needed in real life.  In addition, they discussed the environmental and human health costs of electricity.

Evaluate-Providing Solutions

Students need a practice in this for the new FRQs in 2020. This is surprisingly tricky for students as they often don’t answer the specific question. 

Students need to think of three ways to conserve electricity or energy in each of the following categories. Remember CONSERVING energy is not replacing it with solar, wind, electric cars etc. Replacing with solar, wind, etc. uses the same amount of watts, but in a more sustainable way.

This video has some ideas (warning, the last few seconds are a little racy) 

https://youtu.be/1-g73ty9v04

Students also referenced Disneyland’s energy website: https://publicaffairs.disneyland.com/environment/energy-conservation-and-emissions-reduction/

* 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.