Why Pre-Assessments Are Always a Good Idea: My Ruler Story

In the summer before my first year of teaching science I remember talking to the other science teacher. She casually mentioned that I should teach my students how to use a ruler before doing any labs or activities because many of them wouldn’t know how to measure properly. We were talking about my seventh grade students. Seventh grade. I remember learning how to use a ruler in early elementary school. How could seventh graders not know this basic skill? Surely my students knew how to use rulers.

Just in case my fellow science teacher was right, I decided to add a couple of questions about measuring with rulers to my beginning of year exam. Weeks later, when my students took that pre-assessment, my mind was blown. Over half of my students didn’t know how to use a ruler. They didn’t know you need to start at the first line of the ruler and not at the edge. Furthermore, they didn’t know a ruler can be used to measure in a unit other than inches. Even the students who knew that rulers can measure in centimeters had no idea that rulers are marked with millimeters too. It was like rulers were some rare, mythical object instead of a basic tool found in most classrooms.

Pages from my students' INBs about using rulers properly.
Get these Metric Length INBs in my store.

Thankfully, I became aware of the issue in the first week of school and could easily and quickly fix it. We had a special lesson on rulers and students added measurement and ruler information to their INBs. I made sure my students could use rulers properly before proceeding to the more complex stuff in science. Any time we had a lab or unit involving length, I reviewed ruler skills to make sure my students still had it down. Had I not known about my students’ measurement problems, I would have spent much of the year wondering what was up with my students’ answers and why lab and activity results were wonky. The pre-assessment saved my students from frustration and lost learning time.

This experience taught me to never assume that students come to class with certain knowledge and skills. Whenever possible, I check to see what students know before beginning a new lesson or unit. If students don’t know the basics, then they get overwhelmed quickly, shut down, and don’t learn. Doing a precheck can be as easy as having students raise their hands in answer to a yes or no question, eavesdropping on student discussion of a topic, or adding a question to students’ bell work. If you notice that students don’t understand something, address it before moving on and introducing new content. Knowing about the issue right away allows you to fix it before it gets in the way of student learning.

Have your classes ever shocked you by not knowing something? What was it? When did you find out they didn’t know it? Were you able to address the problem? Share your story in the comments section!

Need measurement resources for your classroom? Check out the some of the metric length resources from my Teachers Pay Teachers store.
Metric Length and Ruler INB Pages
Metric Length Worksheet
Measurement in Science Stations: Tools and Metric Units

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