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What to do about CO2?
Questions in Context:
Do you remember something better when you are asked to think about it?
On the right, in the conversation bubble outlined in yellow, are guiding questions that you should ask the students during the associated step.
Each question should be asked separately – and a short amount of time should be allowed for responses.
Image: Christopher/Wikimedia Commons
Steps, Content & Hints
Main directions and content for the activity are in the boxes to the left with the orange border, like this one.
In a classroom setting, you will lead the students through the activity with a series of questions, the students’ own responses and brief explanations.
Whenever possible, find and affirm what’s right about the students’ answers.
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Green Chemistry Introduction:
Defining Green Chemistry
Have students work in pairs for 30 seconds to come up with a definition for green chemistry. Break down the meaning of both words.
Establish that Chemistry is the science of making products.
Eco-friendly, good for the environment, sustainable.
What is Chemistry? What does chemistry mean to you? Do you think of good things or bad things? Who has heard of companies going green? What does that mean?
Chemists make “stuff,” like materials and medicines. Green chemistry is pollution prevention at the molecular level, the basic design stage. So what is it that green chemists do?
What do Chemists do?
Use wait time. Build off of their prior knowledge. Acknowledge student responses and prompt them for more information. Control the conversation by asking for a certain number of answers.
Chemists are inventors. They help to design just about every product out there.
Traditionally chemists were not taught about the environmental impact or toxicology. We have had many advances and helpful inventions but we have also had inventions that have caused harm to the environment. Green chemists design products taking into account the entire process, energy efficiency, renewable resources, the product itself along with the end-of-life impact of the product.
Is there anything in this room that a chemist invented? What about the desks, paint, floor, etc.
Who has taken medicine? What about a computer or a cell phone?
Has anyone ever seen dry ice before? What’s happening here? Sublimation is when a substance goes directly from a solid to a gas.
Who knows what we/humans breathe out? Carbon dioxide is part of the natural world! What else to do we know about carbon dioxide?
Let’s do a few experiment and find out more about carbon dioxide.
Set the Scene:
Connect the Dots & Introduce the Activity Topic
Connect the dots for them: they are the future scientists who will help to discover and invent the solutions to the environmental challenges.
We will be learning about carbon dioxide today and its effect on the environment.
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Let’s talk about carbon…
Lead the group in a discussion about carbon. Allow the class to share what they know openly, then follow with more guiding questions. See the bubble on the right for some questions!
Examples of things made up of (mostly) carbon
Living things
Diamonds
Graphite
Plastics
Gasoline/oil/coal
The main points here are that:
Carbon is an element on the periodic table
Carbon comes in a lot of different forms
Carbon makes up a majority of what we interact with on a daily basis ( ourselves, the natural world, plastics, etc)
Nearly 10 million molecules with carbon have been discovered and it’s estimated that about 95% of all known molecules have carbon playing an important role in their function!
BUT, where do we get our carbon from to make things like plastics?
Petroleum, what makes up fossil fuels, is a non-renewable resource. Think of going to the library – what do you do when you already have a book and you want to extend how long you have it for? You renew it! So if renewing means you can get something again, non-renewable means that you can’t get it again. We only have so many fossil fuels in the world - once we run out, we will have no way to replace them!
We want to make things that work just as well or better, cost about the same or less AND are better for human health on the environment. With carbon being so important to us, we probably want to think about how we can use green chemistry to find new ways of making carbon products while using more sustainable resources!
What do we know about carbon?
What is carbon? What types of carbon do we know about? What types of things are made up of carbon?
Where do you think we get our carbon from? Is petroleum a renewable or a non-renewable resource?
Have you ever heard of renewable and non-renewable resources? Can anyone tell me the difference between them?
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Introducing pH
As green chemists who want to solve problems, it’s important that we consider our challenge from a lot of different perspectives. One of the most important things we can think about for this is looking at the properties of materials and solutions!
pH, one of the most important properties of a solution, measure of acidity or basicity of a solution. pH is measured on a scale that goes from Acidic solutions have pH’s that fall below 7 while basic solutions have pH’s above 7. 7 is considered neutral.
We are going to explore pH by playing a game doing an activity. Each group will get a table with the 1-14 scale. You will see a few of the common products are in place whether they are acidic (1) or basic (14).
Have we ever heard something called “acidic” before? What did that mean? What do we know about acids and bases already?
Has anyone ever spilled orange juice on a cut before? Did it sting? Do you think orange juice is more acidic or more basic?
Acids and bases neutralize each other. Did you know that our stomachs use a powerful acid (hydrochloric acid) to help digest food? Good thing we have a protective liner.
pH scale activity
We are going to break the class into groups of 4 students. Each group will receive a set of images to match on the pH scale table. Do your best to fit the corresponding images with the pH numbers.
Each group will share out one of their matched images and pH estimate. If available, you can use a whiteboard and fill in the scale for the whole class to see. That will allow you to refer back to the pH scale at any point.
pH in the environment
pH is as important in nature as it is in the lab. Our stomachs are really acidic, which helps break down foods. That’s why when we have an upset stomach, we’ll take “antacids”, like Tums, to help bring the pH of our stomach back into balance. The ocean is also at a certain pH and all of its inhabitants are accustomed to that pH.
What would happen to ocean life if the pH of the ocean changed?
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Do we know anything about CO2 problems or challenges?
CO2 is a greenhouse gas contributing to global climate change. Because CO2 is a gas, it gets trapped in our atmosphere, but it can also be dissolved into water. Where have you experienced CO2 dissolved in water? Where is this excess CO2 coming from?
The burning of fossil fuels produces excess CO2. Why do we need to burn fossil fuels? Energy etc.
Carbon dioxide in the ocean
Today we started with talking about carbon dioxide. Another important way that green chemists think about challenges is by considering how their products and the process of making them impacts the environment. What do we know about carbon dioxide and the environment?
Because carbon dioxide is gas, it can dissolve in water. That’s how we make fizzy drinks like sodas and sparkling water. The name “carbonated beverage” comes from this process of dissolving carbon dioxide in water. With all the carbon dioxide in the atmosphere, some of it ends up dissolving into the oceans.
BUT, how does adding carbon dioxide to ocean water affect its pH?
What is the pH of the sea water? What do you expect will happen when we dissolve CO2 gas into the sea water?
Let’s experiment!
We have an experiment to test what will happen when we dissolve carbon dioxide in the ocean.
Procedure (each student group):
Measure 50 mL of salt water solution using graduated cylinder
Pour salt water into 150 ml beaker
Test the pH of the sea water with pH strip
What happened? Is CO2 an acid or a base? CO2 dissolved in the ocean decreases the pH of the ocean and creates an effect we call Ocean Acidification. This is really harmful to ocean life. Shellfish and coral reefs start to dissolve and break down when the pH of the ocean is too low. Because so much of the life in the ocean is dependent on shellfish and reefs, losing them to ocean acidification could cause some really detrimental problems for the health of the ocean and the parts of our world that depend on the ocean.
Add 5 drops of indicator
Using a protective glove, place 2 pieces of dry ice in a wash bottle with some warm water. (When you close the wash bottle you should have a steady stream of CO2 coming from the spout.)
Insert the wash bottle spout into the container with the salt water solution
Observe and report what happens
Add base & repeat if time permits
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6. OTPIONAL – DRY ICE ICE CREAM
What do we need to make ice cream?
Has anyone every made it before?
OTPIONAL – DRY ICE ICE CREAM
Let’s use CO2 to make ice cream!
Hand out the materials. Each student gets 2 bags, ½ cup of whole milk, 1 tbsp of sugar and ½ tsp of vanilla
Demonstrate putting one bag into the other.
Once students have baggies they add:
½ cup of whole milk
1 tbsp of sugar
½ tsp of vanilla
(Depending on the time and size of the group you may want to pre-measure ingredients) Other wise you can prepare bowls of the supplies for each table and allow students to measure themselves.
Once ingredients have been mixed together remove as much air as possible and seal the Ziplock bags tightly. For added security tape the outside bag closed.
green chemistry technology has 3 criteria: cost, safety & performance
Let’s test the performance of our ice cream.
Create a dry ice bath using salt, water and dry ice (REMINDER: Dry ice is much colder than traditional ice at °F or -78.5°C don’t let students handle with bare hands)
Each dry ice bath will have 2-3 L of water and ½ a container of salt and 500g of dry ice
If the mixture is not slushy enough adjust by adding more water, dry ice and/or salt
Instruct the students to agitate their mixture in the bags while submerged in the dry ice mixture
After we eat our ice cream let’s re-cap
Making the ice cream will take anywhere from minutes depending on the dry ice slurry.
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What to do about CO2?
Carbon dioxide isn’t bad in itself – plants need it for life and so do we! But, carbon dioxide has become a problem in our world because of how much we have put into the atmosphere. Let’s think about what we might do about this!
What do we need to do to solve the problem of CO2 in our atmosphere? What might be the first step that we would need to take? What might make that step difficult?
Carbon capture
The first step to solving our problem with carbon dioxide is figuring out how to get it out of the atmosphere! And there are a lot of scientists around the world thinking about how to do just that.
Each group will be given a set of 6 cards, each with a different picture. 2 of the objects pictured on the cards are currently being used in carbon capture technology. Each group will choose which 2 cards they think are being used and be ready to discuss why they chose the cards they did.
The Green Chemistry Centre of Excellence at the University of York in England has been using waste biomass to invent carbon capture technologies. In their Starbons® invention, they use starch from waste potato peels and alginic acid from seaweed to capture carbon from the atmosphere.
Once we get the carbon dioxide out of the atmosphere, what are we going to do with it? Think back to what we talked about at the beginning of our time together.
But what do we do with our carbon dioxide once we capture it?
Researchers are looking for all sorts of ways to use the carbon dioxide we capture. York is looking for ways to convert the carbon dioxide into one of the building blocks for lithium batteries.
Another company, Blue Planet is using captured carbon dioxide to make building materials. Instead of using limestone rocks that have to be mined as the basis for concrete, Blue Planet turns captured carbon into carbonate rocks. By doing this, they help reduce how much carbon dioxide is released by making concrete and they’re helping reduce how much carbon dioxide is already in the air!
Where do we find lithium batteries? Pretty much an electronic – smartphones, computers, even electric cars!
What types of things are made of concrete? Where do we find these concrete products? What makes concrete so useful?
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Ask what properties would be important when making these products out of captured carbon dioxide. Reiterate the 3 criteria of safety, cost and performance.
In closing, reflect on the activity. Discuss what else might need to be done to fix our carbon dioxide problem. Ask what else we might be able to do with our captured carbon!
Great Job! Scientists ask questions and seek out answers.
Reinforce how green chemistry is the science of solutions!
Who here asks questions about how products are made or why we have certain problems?
Sounds like we have some green chemists in the room. Who thought that this was easy? Who had fun doing this? Do you think that science is something that you can do?
In Closing:
Green chemistry provides the tools needed for creating solutions to environmental challenges.
As a green chemist you can be a part of the solution by inventing better technologies for the future. Also remember that you do not need to be a scientist to make a difference in this world. As an informed citizen you have the power to influence change with your decision making, voting power and purchasing choices.
Any questions?
Wrapping up is always a good time to talk a little more about why you are in the classroom, what you are studying, researching or pursuing as a career.
More information:
Facts About Carbon, LiveScience.com:
Carbon Capture and Utilisation, University of York:
Blue Planet:
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