This formative assessment is one of many that are needed for this unit. You can use this anytime after you think students are familiar with basic operations and conversions in scientific notation.
I start off the assessment by helping students get ready. I offer them pens and pencils, erasers, and scrap paper. Whatever they need to feel comfortable.
When students know about an assessment, I like them to make a study sheet before class begins. I often find that students who make study sheets do better. Interestingly enough, many don't even look at the sheet during the exam. They can write any formulas or notes on the sheet, but it has to be in their handwriting. The idea is that they end up studying in order to create the study sheet. My experience has been that when they sit for the assessment, they no longer need the study sheet.
Scientific notation is a crucial unit. Not only because it dominated our first major common core state exam, but because it builds off of their understanding of exponents and numbers and allows them to ask powerful questions that measure the big and small in our universe. I could break scientific notation into many different standards, but for 8th grade I only pick a few. For this assessment, I ask students to reflect for a moment and rate how well they are doing on the standards for scientific notation. I write each standard in language students can understand. I use active statements, like "I can ____________" in the rubric. I use different scales each year and I am still unsure if there is a number range that best shows progress, but currently I use the 1,2,3 scale:
1 = Just beginning to get it
2 = Pretty much got it
3 = I am a ninja master
Students have 2 minutes to rate themselves on their progress so far in the unit.
This self-assessment is really great for the word problem standard, operation standard and manipulation standard. I usually don't tell students what we are looking at until after the assessment.
This is the task assessment: 100_people_task
It is from the Mars Website: http://map.mathshell.org/materials/index.php
This is the rubric from the site (although the first answer is incorrect): 100_people_rubric
Standards based grading is really exciting and helpful when you involve your students in the process. The idea of a standards based system is to track how students are doing on specific content strands in math (as opposed to an overall grade). The information is much more useful and even better when students are aware of how they are doing.
When you design a standards based system, it is very important to be flexible. I do create specific questions for each strand, but this assessment only has a few questions that touch almost all of the scientific notation content standards.
Note: I always retake the assessment before I give it. It reminds me of potential misconceptions and errors before they happen and helps drive a better class conversation.
We start grading the assessment as a class by swapping with partners. Together we discuss the correct answers and students mark if their partner got the problems wrong. I let students use their own system, but each student must include a key. For example, if a star means correct and a sad face means incorrect, the student must indicate this in their key.
Then we pass out the rubric for grading: Scientific Notation Rubric. The rubric contains each standard, but not every standard will apply to each student.
This is a formative assessment and isn't meant to give a percent grade. Instead, it is meant to verify or contrast a student's perception of their progress. After going through this activity, they should be able to reflect, "yes, I could do that." Or "maybe I need more work on this." The that and this are very specific in this type of assessment. Students will recognize if it is an operation issue, a conversion issue, or even something more general with a word problem.
Since there are only two problems here, I would ask students to give a 2 for one example of good number manipulation and a 3 if there is more than one example. This can be very valuable for the class and I ask students to share any cool ideas they saw. The goal is to see things that make the problem solving process easier.
There are always many "what if" questions here. They often are stuck between the 1,2 and 3 grades (as I always am when grading). However, we try to keep it simple. I say, give a 3 if they really got it, a 2 if there is a minor error and a 1 if they are just starting to get it.
Once we are done, we swap back and talk for 2 minutes. Then we try a new question.
I ask: "How many people in the world are children?"
I ask the students to solve this without a calculator and submit it to me as an exit ticket. I need to to review these tickets and see how the class is doing.