1. Biology Wednesday, September 28, 2016
Welcome to class.
Get out your “Molecular Modeling” sheet from yesterday and prepare to share your answers.
If students were absent yesterday, the worksheets are in the crate in the back of the room.

2. Comparing photos of reactant and product molecules
Start by making the molecules and energy units of the reactants and putting them on the reactants side, then rearrange the atoms and energy units to show the products.
Water
Chemical change
Carbon
dioxide
Ethanol
Credit: Michigan State University
Show students Slide and ask several students to explain what they did yesterday using the pictures on the powerpoint.
They should talk about how they created atomic-molecular models of ethanol combustion. The reactants (what they started with) were liquid ethanol and oxygen, chemical energy was stored in the bonds of the ethanol (modeled by the twist ties). When it was lit the ethanol burned and produces water and carbon dioxide. The chemical energy was converted to light, heat, and motion energy. They should also reference the rules.
Oxygen
Reactants
Products
Remember: Atoms last forever (so you can rearrange atoms into new molecules, but can’t add or subtract atoms). Energy lasts forever (so you can change forms of energy, but energy units can’t appear or go away)

3. Record your results Record your results for your products.
Show students the slide or the worksheet under the document camera. Have the students check the table in their worksheet that explains what they ended with.
Have students verify that the number of atoms before and after remained constant: Atoms last forever! Tell students that this means that the number of atoms before and after the reaction does not change.

4. What happens to atoms and energy when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
As you show slides in the PPT have student describe what they are seeing. This is to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Water
Products
Oxygen
Heat and light energy

5. What happens to atoms and energy when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
Show slides in the PPT to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Water
Products
Oxygen
Heat and light energy

6. What happens to carbon atoms when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
Show slides in the PPT to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Focus on carbon atoms.
Water
Products
Carbon atoms in ethanol become part of carbon dioxide molecules.
Oxygen
Heat and light energy 6

7. What happens to oxygen atoms when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
Show slides in the PPT to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Focus on oxygen atoms.
Water
Products
Oxygen atoms become part of carbon dioxide and water molecules.
Oxygen
Heat and light energy

8. What happens to hydrogen atoms when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
Show slides in the PPT to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Focus on hydrogen atoms.
Water
Products
Hydrogen atoms become part of water molecules.
Oxygen
Heat and light energy

9. What happens to chemical energy when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
Show slides in the PPT to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Focus on chemical energy.
Water
Products
Chemical energy is transformed into heat and light energy.
Oxygen
Heat and light energy

10. What happens to atoms and energy when ethanol burns?
Carbon Dioxide
Ethanol
Reactants
Chemical change
Credit: Craig Douglas, Michigan State University
Show slides in the PPT to help students make connections between what is happening in the animation and the molecular models they made.
For each slide, focus on different atoms and forms of energy and how they change. The animation draws attention to where they atoms begin and end in the reaction.
Focus on the rules that “Atoms last forever!” and “Energy lasts forever!”
Water
Products
Atoms last forever! Energy lasts forever!
Oxygen
Heat and light energy

11. Discuss with the class
Did the number and type of atoms stay the same at the beginning and end of the chemical change? ____
Did the number of twist ties (representing energy) stay the same at the beginning and end of the chemical change? ____
Why do the numbers of atoms and twist ties have to stay the same?
Show slide 22 in the PPT.
Complete the “check yourself” questions with the class in Part C.

12. Writing a Chemical Equation
Chemists use chemical equations to show how atoms of reactant molecules are rearranged to make product molecules.
Writing the equation in symbols. Chemists use an arrow to show how reactants change into products.
Equations must be balanced. Remember: Atoms last forever.
Try it: Can you write a balanced chemical equation to show the chemical change when ethanol burns?
Help students write a balanced chemical equation.
Tell students that now that they have represented a chemical change using molecular models and in animations, they will represent chemical change by writing the chemical equation.
Show Slide 23 of the presentation to guide students through the process of writing a balanced chemical equation for the combustion of ethanol. Tell students that these rules apply to all chemical reactions.
Tell students to write their equations in Part C of their worksheet.
Have students write their own chemical equations before comparing them with the one on Slide 21.

13. Chemical equation for ethanol burning
C2H5OH + 3O2  2 CO2 + 3 H2O
(in words: ethanol reacts with oxygen to yield carbon dioxide and water)
Have students write their own chemical equations before comparing them with the one on Slide 24.

14. Carbon: Transformations in Matter and Energy
Environmental Literacy Project Michigan State University
Systems and Scale Unit Wednesday, September 28, Title: Explaining Ethanol Burning EQ: What are the chemical changes involved in this reaction?
Image Credit: Craig Douglas, Michigan State University
Have the students put this title and essential question in their notebook – this will save the page for them to glue in the work they are doing today.

15. Unit Map
You are here
Use the instructional model to show students where they are in the course of the unit.
Show slide 2 of the 4.1 Predictions about Ethanol Burning PPT.
Again, see if a student will explain this diagram to you. It is a map of the unit we have been studying.

16. Revisit your arguments (yellow)
Think about what you know now that you didn’t know before. What have you learned?
Revisit students’ arguments about what happens to ethanol when it burns.
Show slide 3 of the Grading the Explanations Tool for Ethanol Burning PPT.
Tell students that this activity’s purpose is to develop explanations for what happens when ethanol burns.
Return each student’s copy of 4.3 Evidence-Based Arguments Tool for Ethanol Burning (they have this yellow paper in their notebook) and have them review their arguments before they completed the molecular modeling activity.
Ask them to think about what they know now that they didn’t know then.

17. Constructing explanations
Consider the following as you construct your explanation:
Evidence from the investigation
What you learned from the molecular modeling activity
Three Questions Handout
Have students complete the Explanations process tool.
Show slide 4 of the Grading the Explanations Tool for Ethanol Burning PPT. Give each student one copy of 4.5 Explanations Tool for Ethanol Burning.
Tell students that in this final step of the investigation, they will combine everything they learned about what happens when ethanol burns into one explanation.
Remind them to consider both their evidence from the investigation as well as what they learned in the molecular modeling activity to construct their explanations. Give them about 5 minutes to work on this individually without talking. They can use their notebook.
Give students about 10 minutes to complete the Explanations process tool.

18. Comparing Ideas with a Partner
Compare your explanations for each of the Three Questions.
How are they alike?
How are they different?
Check your explanation with the middle- and right-hand columns of the Three Questions handout. (bright orange)
Consider making revisions to your explanation based on your conversation with your partner.
Have students share explanations with each other.
Show slide 5 of the Grading the Explanations Tool for Ethanol Burning PPT. Divide students into pairs and have them compare explanations for the Three Questions and the final explanation on the process tool.
Invite students to share their ideas with the class. Use the Three Questions Poster (or Handout) as a reference. Have students check their explanations with the middle and right-hand columns of the poster to make sure they are following the “rules.”

19. Matter Movement Do you have:
An arrow showing ethanol evaporating and going into the flame
Display slides 6-8 of the PPT. Have students compare their answers to the Matter Movement Question with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
Ethanol

20. Matter Movement Do you have:
An arrow showing oxygen or O2 entering the flame
Display slides 6-8 of the PPT. Have students compare their answers to the Matter Movement Question with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect. O2
Ethanol

21. Matter Movement Do you have:
An arrow showing carbon dioxide or CO2 leaving the flame
An arrow showing water vapor or H2O leaving the flame
H2O
CO2
Display slides 6-8 of the PPT. Have students compare their answers to the Matter Movement Question with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect. O2
Ethanol

22. Matter Change
What is the name of the chemical change that happens when ethanol burns? Combustion
Display slide 9-10 of the PPT for the Matter Change Question and repeat the process above.

23. Matter Change
What molecules are carbon atoms in before the chemical change? Ethanol or C2H5OH What other molecules are needed? Oxygen or O2 Write the chemical equation for this change: C2H5OH + 3 O2  2 CO2 + 3 H2O
What molecules are carbon atoms in after the chemical change? Carbon dioxide or CO2 What other molecules are produced? Water or H2O
Chemical Change
Display slide 9-10 of the PPT for the Matter Change Question and repeat the process above.

24. Energy Change
What forms of energy go into this chemical change? Chemical energy or C-C and C-H bonds
What forms of energy come out of this chemical change? Light and heat energy
Energy transformation
Display slide 11 of the PPT for the Energy Change Question and repeat the process above.

25. Finish and turn in:
Using the discussion and notes on the front of the page, complete the written explanation on the back. When it is complete and accurate – turn it in to the folder.
Check that all of your papers are glued in while you wait for your classmates to finish.

26. Telling the Whole Story
Question: What happens to ethanol when it burns?
Does your story include these parts?
Matter movement: Ethanol evaporating and going into the flame and oxygen going into the flame from the air.
Matter change: Ethanol reacting with oxygen to produce carbon dioxide and water.
Energy change: Chemical energy in ethanol being transformed into light and heat energy.
Matter movement: Carbon dioxide and water leaving the flame.
This slide will not be displayed for the students today – I’ll do it on Friday.
Display slide 12 of the PPT for the final explanation. Have students check that their story includes each of the parts (matter movement, matter change, energy change, and matter movement). If students don’t have all four parts in their explanation, instruct them to add to their explanation using a different colored writing utensil.

27. How have your ideas changed?
Look over your process tools for the unit (Expressing Ideas Tool, Predictions Tool, & Evidence-Based Argument Tool).
Write a reflection in your notebook: Include the following:
How have your ideas changed related to:
Scale (macroscopic, atomic-molecular)?
Matter Movement?
Carbon?
What do you know about ethanol now that you didn’t know before the investigation?
Have the students write a reflection in their notebook about how student ideas have changed over time.
Show slide 13 of the Grading the Explanations Tool for Ethanol Burning PPT. Have students look back over their process tools for this unit.
Have students consider how their ideas changed with regard to scale, movement, and carbon.
What do they know about ethanol burning now that they didn’t know before the investigation?