Earth's oceans are a carbon sink, which is a place where carbon is stored long term. Oceans absorb carbon dioxide from the atmosphere. It reacts with seawater, creating carbonic acid, which in turn lowers the pH of the ocean. This phenomena is known as ocean acidification. It will only get worse as we release more carbon dioxide into the atmosphere. Oceans currently have a pH of around 8.1, but it is projected to lower to 7.7 by the year 2100.

What is the impact of ocean acidification on marine life?
Research is still being conducted on this, but there are a few things we know for sure. First, organisms that rely on carbonate to build their shells and exoskeletons will have less available. These organisms include coral, mollusks, sea urchins, starfish, and zooplankton to name a few. If they struggle to build shells, they are more likely to be eaten by predators and it can create a trophic cascade up the food chain. Other impacts could include lowering the blood pH of fish, changes in reproductive ability of marine life, and impeding with organisms ability to send chemical signals.

Ocean Acidification Lab
An easy way to show students the impact of ocean acidification on marine life is by soaking seashells in ocean water with various pH levels.
For this lab you will need (per group): 3 cups or beakers, 3 seashells, water, salt, vinegar, an electronic scale, and pH paper. Seashells can be purchased at craft stores, and I've even found them at the dollar store in the craft aisle.

Start by mixing up simulated ocean water (3.5% saltwater solution). Students will put ocean water in the first beaker, 75mL of ocean water and 25mL of vinegar in the second beaker, and 50mL ocean water and 50mL of vinegar in the third beaker. Next, have students take the mass of the seashells over the course of 3 days and calculate the percent change in mass. They will see the vinegar eat away at the seashell and a large reduction in mass. You can also have them measure the pH of the liquids over 3 days and see how it changes as carbonate is released (enter discussion on buffers!)

Following the activity you can discuss ways students can lower their carbon footprint so we can slow the rate of acidification in the future. If you are interested in a powerpoint lesson on ocean acidification and a lab write up for this activity, you can find it HERE.

Bored of teaching the carbon, nitrogen, water, or rock cycles? Spice things up by having students take a ride through each of the cycles with these interactive games!

In these games, students will roll a die at stations throughout the cycles and pick up paper tokens along the way. For example- in the rock cycle game, the stations include: igneous, sedimentary, and metamorphic. In the water cycle game, stations include: clouds, plants, oceans, animals, groundwater, soil, lakes, rivers, and glaciers.

To set up the game you will need to print out station cubes and fold them (cardstock works best and will extend the life of your cubes). You will also need to print and cut station tokens and place them in cups around the room.

Assign students a random station to begin at. They will start each round by picking up a paper token and placing it in their cup. Then they will roll the die and see where it tells them to go next. I let my students go at their own pace and tell them once they have 15 tokens in their cup to head back to their seats. Then they tally up where they have been and start answering the questions on their lab paper.

Students really love these games and often ask to play again the next day. I also love that it solidifies how things move through the cycles and you can even discuss where things are stored throughout the cycle. For example- in the water cycle, water molecules can be frozen in glaciers for hundreds of thousands of years. Or in the carbon cycle, carbon can be stored in fossil fuels for millions of years. If students get stuck at a station over and over it's good to discuss why.

Want to check them out for yourself? Click on the images below!

Ecological succession can seem like a simple process... grass, shrubs, small trees, big trees. But how does an ecosystem evolve from nothing? I always begin this lesson by showing students a picture of earth as it was first developing and a picture of the earth today. Next I ask students- how did we go from this.... to this? How did our thriving ecosystems evolve from nothing? It really gets them thinking and leads to great class discussions. 
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Check out these resources to help your succession lessons be a success!  (pictures courtesy pixabay)

1. Here is a powerpoint and card sort activity I created that you can use to introduce ecological succession.

2. This lesson plan from National Geographic shows the formation of a coral reef. It's pretty cool to look at succession underwater, not just below water!

3. Here is a free card sorting vocabulary activity I found on teachers pay teachers.

4. Here is a free lesson plan that looks at the succession that occurred following the eruption of  Mount St. Helens

5. Here is a succession board game you can have students play. Looks fun!

6. Here is an online interactive game from Bioman on succession.

7. Succession occurs within aquatic ecosystems as well. Have students look at the succession of protozoa using this Carolina lab. (Don't have the funds to order protozoa? Here are directions to make your own hay infusion!)

8. Most of your students have cell phones, so have them go outside and take pictures of primary and secondary succession in their neighborhoods. They can upload them and create a photo journal.

I hope you lichen these lesson options! (ok... that was lame)

WHAT IS CITIZEN SCIENCE?
Citizen science is when the public participates in scientific research. Every-day citizens share and contribute data with the goal of increasing scientific knowledge. You do not have to be a trained scientist in order to participate.

WHY YOU SHOULD TRY IT
Citizen science is great to do with students because:

• The data they collect in class is meaningful! Students will be more precise with their data collection if they know it is going to a greater cause.
• Many studies rely on citizen scientists in order to collect regional data.
• When you get students exploring, you are helping to grow their interest in the natural sciences. The future is full of STEM careers, so let's get them interested now!

PROJECT IDEAS
Ready to try it out? Here is a list of websites and project ideas to get you started.

1. CitizenScience.gov is a government website that has a TON of project ideas and is a great place to start. You can collect data that will be used by NOAA, USGS, National Science Foundation, and even NASA.

2. The Great Backyard Bird Count is a website run by the Audubon that encourages students to get outside and start birding.  They are looking for regional data where people can upload pictures and species of birds they see in their neighborhoods. Time to dust off those binoculars!

3. National Geographic has a list of citizen science projects, ranging from wildlife observation, measuring night sky brightness (light pollution), butterfly census, listening for frog and toad calls, and more. 

4. SciStarter.org is a website put together by Arizona State University and the National Science Foundation. You can search for projects near you or online only.

5. Project Green Challenge is a website that gives students environmentally-themed challenges. You can register your school and enter to win prizes!

6. Zooniverse is "people powered research." This website has a ton of ongoing projects that also venture into other content areas outside of the natural sciences.

7. inaturalist Do you ever take pictures of insects and cool species in your yard or neighborhood? inaturalist is a website (and phone app) that allows you to upload pictures of your findings and share/discuss with fellow naturalists.

8. Captain Planet Project Hero is a PBL driven website where students can help threatened species and ecosystems in their area.

9. The GLOBE Program is looking for people to contribute data for cloud types, mosquito habitats, and land cover observations.

10. Project Budburst was created by Chicago Botanical Garden. Their goal is to uncover the stories of plants and animals affected by human impacts on the environment.

11. Gorongosa Webcams If you've ever used curriculum from Biointeractive, you know it's pretty stellar. In this lesson students study webcams from Gorongosa National Park in Mozambique and do animal identification.

12. Pollinator Live is a website that includes links to a bunch of citizen science projects centered around attracting and monitoring pollinators in your area. Teach students the importance of pollinators!

The water cycle is taught starting in elementary school. It seems like in high school biology when I get to the biogeochemical cycles (water, carbon, nitrogen, and phosphorus) the water cycle gets glossed over because we assume the students know it and it's too basic. But water is vital to life! It's important to take some time to dig a little deeper with the water cycle and there are ways to ramp up the rigor. Check out a few activities you can use to take a deep dive into the water cycle:

TAKE A RIDE THROUGH THE WATER CYCLE
Even though this activity is good for younger grades, older kids still enjoy it. In this activity, students roll cubes that tell them how to move through the water cycle. It allows students to review the steps of the process but also realize where more water is stored within the biosphere. You can download the game cubes here.

WATER FOOTPRINT
How much water do students use each day? At watercalculator.org, they can calculate their water footprint.

EVAPOTRANSPIRATION AND URBAN HEAT ISLANDS
In this free lab from ASU, students see first hand how evapotranspiration from trees can cool down an area and have an impact on the urban heat island effect. You will need clay terra-cotta pots and thermometers. You can download the lab for free HERE. If you would like to see more resources dealing with urban heat islands, check out this blog post.

WHERE DID EARTH'S WATER COME FROM?
Water has been around on our planet for a very long time. But where did it come from in the first place? You can students this Ted YouTube video:

SCALED MODEL OF EARTH'S WATER
We tell students that the amount of fresh water we have available is very small compared to the total amount of water on earth, but does it really sink in? In this lab, students create a scaled model of where the water on Earth is located. There are 4 different versions of this lab so you can differentiate based on the amount of inquiry and math you would like your students to do. By the end of the lab, students will see that our freshwater supply is very small and hopefully realize how important water conservation is.

VIRTUAL WATER
What is virtual water? It is the amount of water used to produce a product. In this activity from California Academy of Science, students learn about the hidden water footprint of different products. You can download the lesson here.

THE GRACE SATELLITES
How do scientists monitor groundwater levels? NASA tracks water levels from space using the Grace satellites- super cool! They orbit the Earth and scientists measure the gravitational pull on the satellites in order to monitor how much water is underground (more groundwater = more dense = more gravitational pull).
You can find an article students can read about the grace satellites here, and check out some interactive maps with satellite data here.

ICE CORE LAB
What can we learn from ice cores? In this lab, students learn about how ice cores form, what we can learn from them, and how they are analyzed. It takes about 4 days to set up on your part, but the students love looking at these simulated ice cores. You can read a full blog post on how I made them here.

WATER DOCUMENTARY
There are a ton of documentaries out there on water shortages and conservation. I showed my students one titled "Beyond the Mirage" that is available on YouTube. I chose it because it is centered around Colorado River water, which feeds into my home state of Arizona. If you live in one of the 7 states that uses Colorado River water, I recommend this video. If you would like video questions to accompany the video, click here.

I hope these help and you spend an extra day or two digging a little deeper into the water cycle. If you have any other favorite activities, leave them in the comments!

Models can be powerful tools when teaching science. They allow students to visualize concepts that can be difficult to picture in their heads.

If you ask students what the most abundant gas in the atmosphere is, their first guess is usually oxygen. And when you say no, their second guess tends to be carbon dioxide. When we talk about the composition of the atmosphere and the effect of greenhouse gases, students may picture the atmosphere being FULL of carbon dioxide... and rightfully so- statistics estimate that 45 billion tons of carbon dioxide are released every year. But how much is that?

I wanted to build a model of the atmosphere so students could see that there isn't very much carbon dioxide in the atmosphere relative to other gases.

I like that it is easy to see how much nitrogen is in the atmosphere compared to oxygen and other gases. So much easier for students to visualize!

I want to point out that whenever you use models in class, you need to discuss with students any limitations the model might have to avoid misconceptions.

1. This model is limited to 4 types of gases. There are other gases in the atmosphere such as neon, helium, water vapor, and methane, but they are in such trace amounts I left them out of the model.
2. The gases in our atmosphere are more dense near the earth's surface and thin out as you go up in elevation. This is because gravity pulls down on the gases (and why it is difficult for hikers on Mt. Everest to breathe- there is a lot less oxygen up there!)
3. If you teach chemistry, you might want to point out that not all gas molecules are exactly the same size, as they are in this model.
4. It is good to discuss that even though carbon dioxide molecules are few in number, they still play a large role in global climate change.
5. If you teach biology or environmental science and review the biogeochemical cycles, this can be a good time to point out that gases in the atmosphere aren't static- they are constantly moving through cycles. Producers take in carbon dioxide and release oxygen during photosynthesis, consumers take in oxygen and release carbon dioxide during respiration, and bacteria take in nitrogen through nitrogen fixation. But it IS true that we are releasing carbon dioxide to the atmosphere faster than ever before.

Overall, the entire thing only cost me $9 to make and I had enough spheres left over to make another. Pretty cost efficient compared to ordering one from a science supply company!

If you would like to check out other resources I use when teaching about gases in the atmosphere and the biogeochemical cycles, check out this blog post.

If you read my blog post on recommended summer science reads, you saw my confession that I'm not generally a big non-fiction reader. I love to read, but fiction is my go-to.

As I was compiling a science book list for students and teachers, I kept seeing and getting recommended The Serengeti Rules by Sean Carroll (If you've used any HHMI videos in your class, you know who he is). I decided to check it out from the library and I'm so glad I did. The first section of the book discusses cellular rules of regulation. When I first started reading I was thinking "I thought this was an ecology book!" but what's fascinating is he relates cellular rules of regulation to ecological rules of regulation in later sections of the book. So many concepts cross over. For example, cells maintain balance using homeostasis, ecosystems maintain balance with carrying capacity. Cells populations are regulated from the bottom up by food availability, and so are animal populations. Cellular process such as enzyme activity are regulated by  negative feedback, while populations are regulated by negative feedback in the form of trophic cascades. It was cool to see the cross over and I kept thinking "this book is perfect for honors and AP biology students!"

As I set out to look for supplemental student and teacher resources for this book, I came across the official version published by the Princeton Press. There is a ton of great information included in that document, but it didn't suit my teaching style. I wanted students to pull out the main ideas and have clear graphic organizers to fill out as they read the book without getting caught up in the nitty gritty details. So I went back through the book and created my own resource for students that is more user friendly. It includes writing prompts, graphic organizers, chapter discussion questions, and more. Below are some images of what the resource looks like (page borders differ depending on if they are a pre-reading, during reading, or post-reading activity).

HHMI also has some additional resources that supplement the book that you can find on their website. And most exciting.... they are coming out with a Serengeti Rules documentary some time this fall! The trailer looks fascinating and I can't wait to see the full movie. Keep your eyes peeled- the HHMI website  frequently offers free DVD's to classroom teachers.

I hope you enjoy the book!

One of the most common projects for invasive species is for students to make a "Most Wanted" poster. Students do research on an invasive species of their choice and create a wanted poster that includes facts about the species and what they would be "wanted" for. It can be fun, but after doing it for a few years I was looking for something different. Below are some articles, videos, activities, and simulations you can add to your invasive species unit!

This video from Ted is a great introduction to what invasive species are:

This is a fun interactive activity where students act as fish and compete for food and see the effect of invasive species on native species. Requires minimal materials!

This "Fearsome Frog" video from National Geographic is not new (it feels very 90's) but since I'm a local Arizonan my students love watching it since it hits home. This video explores how Bullfrogs are an invasive species that were brought to Arizona by the government and what people have done to try and control the population. At the end of the video I ask students to brainstorm ideas on what we could do to eliminate them from our local ecosystem.

Instead of the go-to "Most Wanted" poster, what about having students create an obituary? In this activity students create an obituary for either an invasive species that has finally been exterminated, or for a native species that has gone extinct in an area due to invasive competition.

Do you have any budding artists in your class? Or students that like to read comics? Check out this lesson plan and comic strip from Oregon State University on invasive crayfish.

If you are looking to include some literacy, newsela.com is always a great source of articles. Here is an article about how technology can be used to combat invasive species. Newsela does require you to sign up and login, but is free to use. Bonus: You can also change the lexile of any article! Great for differentiation.

Have you checked the website of your local fish and wildlife department? Arizona Game and Fish created this poster of our 10 most invasive species. Students enjoy looking at the poster and discussing how many of them they have seen or knew about. Head over to your local site and see what you can find!

The website "Species in Pieces" is more about endangered species opposed to invasive species, but as we know many species are endangered due to invasives. This website has information about 30 animals that are endangered, gives facts about each animal, and includes a link to a youtube video. Worth checking out! 

If you have the ability to get your students outside, try a citizen science project! Eddmaps.org is a website from University of Georgia built for early detection and mapping of invasive species. You need to register for an account, but you can collect data and report your findings straight from your phone. It would be fun to have your students contribute data to a meaningful and reputable project.

If you live on the east coast, this 5 module curriculum by Maryland's Department of Natural Resources includes a ton of free lessons for all grade levels. It focuses on aquatic invasive species.

I hope those help spruce up your ecology unit! If you have any other favorite lesson ideas for invasive species, feel free to leave them in the comments!

One of my favorite case studies to examine with students is the tragedy that occurred at Lake Nyos. Located in Camaroon, Africa, Lake Nyos is a lake that formed in a volcanic crater. While villagers thought the volcano was dormant, it was slowly releasing carbon dioxide into the lake. One night in 1986 the carbon dioxide built up enough that the lake overturned and all the carbon dioxide was released into the atmosphere. Since carbon dioxide is more dense than air, thousands of villagers and livestock died in their sleep that night of asphyxiation.

While it is a devastating story to learn about, it is good in the sense that it can be applied to so many science concepts. Biology teachers can bring it up when learning about the carbon cycle. Earth science teachers can discuss the story during their volcanoes unit. Physical science teachers can use it to introduce density of gases. It's a phenomena that is so versatile!

I begin the lesson by showing this video clip from National Geographic on Youtube. It gets the students 100% engaged and doesn't reveal why this mystery fog killed the villagers:

Following the video clip I have students read an article I wrote about what happened at Lake Nyos and the science concepts behind it. You can find the article HERE if you would like to download it (appropriate for grades 7-10).


Then at the end of class I like to end with a demo showing how carbon dioxide is truly more dense than air. All you need are 3 birthday candles, some clay or play-doh, a container, baking soda, and vinegar.
Cut two of the candles shorter so all the candles are different heights. Stick them to the bottom of a container with clay. Sprinkle the bottom of the container with baking soda and light the candles. Have students predict what will happen when you pour some vinegar into the container. Students will observe the lowest candle extinguishing first because the dense CO2 that is being formed stays nearest to the bottom of the container. (I do it under the document camera so all students can watch, but if you trust your students with matches you can have them do it in small lab groups instead). 

I hope your students enjoy this lesson- I know mine do! It's simple, engaging, and a story your students won't forget.

I currently live in Phoenix, AZ, which is the 6th largest city in the United States. Considering our large population size and desert climate, we have a huge problem with heat. In the summer it is not uncommon for the temperature to stay above 100F all night. It can be miserably hot! 

An urban heat island is an urban area that has a much higher temperature than the surrounding areas. Students probably haven't heard the term coined before, but can easily explain it to you. If you ask them why downtown Phoenix is hotter than some of the surrounding pockets of town, or ask them why it's cooler to stand under a tree than under a metal awning, they can explain it to you. As I was preparing to teach this concept to my students, I found (and created) a few resources you may want to check out!

Urban Heat Island Lab
In this activity, have your students head out around your school campus and measure the temperatures of different materials. Students will compare surfaces such as cement, asphalt, dirt, and grass in the sun and the shade. Students can brainstorm ways to improve the school campus and lower the overall temperature (and electric bill!) of the school. 

ASU Ecology Explorer Lessons
Arizona State University has a few lessons on urban heat islands that are great! This first lesson uses thermal images to teach students that urban heat islands are a night-time phenomenon, opposed to day time. Students will compare thermal images and try and figure out which ones were taken during the day and which were taken at night. 
This second lesson also uses thermal images, but students have to predict which object in the picture would be the hottest, and which would be the coolest. (If you don't have access to a color printer, you can just project the images on the board). 

Climate Central Interactive
Do you live in an urban heat island? This fun interactive looks at 60 cities across the US and gives you data on each one. Check it out and see if your city is listed!

Citizen Science
Start a citizen science project, where your students collect data about temperatures in your area, brainstorm ideas to mitigate the problem, and reach out to scientists, politicians, or even school board members to try and make a difference! It could be something as simple as planting a tree on campus or taking them to a community garden, to something larger like having students apply for grant money to have solar powered cell phone charging stations installed. If you let the students decide what impact they want to make their work ethic may surprise you! 
​(One great nonprofit organization that plants trees is onetreeplanted.org. They plant a tree for every dollar donated!) 

With climate change being a current global crisis, we have an obligation to teach students how to make more sustainable decisions. If every one of your students made a small change in their front yard we could see incredible results. Who knows, you might have a student in your class that will major in urban planning or sustainability!