Looks like this week’s theme is: ALGEBRA
We were working on finding the average atomic mass of elements’ isotopes. This involved percentages, solving for one unknown…and solving for two unknowns. Most students were comfortable with percentages and solving for one unknown. Once we got to solving for two unknowns, we kind of gave up. There were a couple of students who tried really hard and looked at the textbook copy in the classroom, searched “how to solve two unknowns”, or used AI tools to solve the problem.
Challenge 1: How to deal with percentages. Students did not know that dealing with percentages meant that 8% = 0.08 = 8/100. Once we got over this, some continued on with the journey of solving for abundance of isotopes in a sample. Another one was 100% = 1 whole. We were having trouble understanding 100% of the pie is equal to 1 pie.
Challenge 2: Finding the average. One of the problems gave the masses and abundance of 5 isotopes. Titanium-46 through Titanium-50. They were supposed to calculate the average atomic mass of titanium. Instead of dividing by 100, students were dividing by 5 because they couldn’t not differentiate between the number of different isotopes from the number of occurrences. I started calling the masses “test scores” and the percent abundance “students”…and then it became easier to understand what the class average was. As soon as I said average atomic mass, the analogy was no longer understood.
Challenge 3: Finding two unknowns. One of the problems gave the average atomic mass, but did not give the abundance percentages. Instead, students were to find the abundance percentage. Students did not have the confidence to find it. There were a couple who were able to go back to work as soon as I said substitution method or find out what y is equal to. The majority of the students were able to work it out and apply it to the next problem when I solved the first problem of its kind. A few were very much confused from the start to finish.
Once they solved for Boron-10’s percentage, very few were still asking how to find Boron-11. After giving two options, students forgot where 1 = x + y came from.
Overall, it was a very arithmetically taxing day, but I didn’t think it was difficult. I admitted to the students that when I sat down to make the answer key for this worksheet, I didn’t really want to because I was being lazy. But in the end, the actual algorithm and steps to completing it weren’t hard, I just didn’t want to. I’m hoping that motivated them to think of algebra as easy and not something I want to do as opposed to something that is hard and only for smart people.
Exit Ticket Retake
Consistent with the theme, the exit ticket had some challenges as well. It wasn’t really hard mathematically, protons = atomic number, protons + neutrons = mass number, protons + electrons = 0, etc. Conceptually, it was new and they really needed another practice. I would like to somehow have students whiteboard some problems so that they think through it together.
Learning with Ms. Medrano 