Lesson 1: The Mole

For the teacher:

Class set up: Students are arranged in sets of four that can be broken up into pairs

• Phenomena: Have students count big objects located in bins (washers, pennies, beads, glue sticks, etc.). Then provide students with a paper towel and dixie cup of salt. Have the students count the grains of salt. They will most likely struggle with this and moan and groan.
• Generated Questions: Have students complete Inquiry Reflection (see below) parts 1 and 2. Part 1 is what they noticed about the differences in counting. How they did it. What was easy, what was difficult, etc. Part 2 are questions that the students generate about the phenomena. This is all done in groups electronically on Google Docs.
• Investigation: Students will work on the ChemQuest* investigation where they read through information, answer critical thinking questions, and then compare their work with a partner. Students will confirm their answers with the teacher in class discussion and put answers on the board.
• Task: Teacher tells students to resume Inquiry Reflection handout to complete the “Task” section. “Discuss with your partners and write a written explanation of how you count something that is too small to see?” Students submitted work electronically, but can be submitted on paper.

*ChemQuest is copyrighted material, but can be found and purchased here:

Student Sample: (Completed by 11th grade students)

Inquiry Reflection--The Mole

Names: Mattie, Brooke, Payton, Channing

• Phenomena: What do you notice? What did you do?
  • There is A LOT of grains of salt→ attempted to count but failed miserably
  • The cotton swabs were a easy to count→ picked them up one by one and counted them

• Questions: What questions do you have about this?
  • How are you suppose to count all that salt in a cup by hand?
  • What is an equation you can easily do to calculate the exact number of the salt?
  • Can you use a universal equation to count other things like grains of salt?

• Investigation: Work on the ChemQuest to further investigate the mole unit. Here is a student sample.

• Task: Discuss with your partners and write a written explanation of how you count something that is too small to see?

If something is too small to count, you can weigh it and use a formula to calculate how much of the small object(s) there is/are. You will need to use Avogadro's number and the molar mass of the compound that you are counting. In our case, we would use NaCl which has a molar mass of 58.44 g/mol. Once we know how many grams of salt we have, we could calculate the actual number of salt molecules.

Annotation:

This lesson was aligned to NGSS HS-PS1-7.

This lesson was great for the students because as soon as they were asked to count the salt they thought I was nuts for asking them to do such a daunting task. When they looked at me or asked me for help, I just kept repeating "count the salt." There was a range of what students did to count the salt. Some students literally tried to count each grain. Some tried to count the number of grains in a square inch (they used a prior knowledge from an activity they apparently did in another science class where they counted the blades of grass on the football field) and calculate the number of square inches of salt I gave them. A few groups tried to weigh the cup of salt, but didn't really know what to do after they weighed it. After about 6-7 mins of attempting to count the salt, I had the students stop and open up an Inquiry Reflection on a shared Google Document (this could be paper based). The students in their groups had to respond to the phenomenon and question sections first. I gave the students 6 mins to respond to these section electronically. Once they responded each group worked on a ChemQuest investigation for 25 minutes. This handout has the students read and work through information and forces them to think critically about the content. It is not just a typical worksheet. The answers aren't simple. Students had to take provided examples and apply them to their work. The questions are more explanation based rather than recall. The students could work together on this activity, and I walked around to ensure that they were focused, on task, and addressed any misconceptions. When asked a question I was sure to just guide the students and not directly answer them. I wanted them to figure it out. The PAYOFF is so much greater when they figure it out. In fact, one student who typically earns C's was quoted, "I like this...I feel smart!" and he beamed with pride. Finally, when students finished, we had a 10 minute discussion where we worked through some problems on the board to ensure proficiency with the content. The last 10 minutes of class were devoted to each group having their discussion to respond to the task prompt. The students spent the time discussing and could actually write/type their answers for homework. The beginning of the next day's lesson was a discussion of some of their answers to the task.