To begin the lesson, I give each group of students a scenario card containing a unit conversion error scenario from the US Metric Association and ask the students to read and discuss it as a group. After the groups have read through their scenarios, I ask the students if it is important to include proper unit labels on measurements. They respond that it is important, and I ask them to explain how they know. I then have each group share their scenario with the class. After each group has shared their scenario, we discuss the importance of using proper units and converting units appropriately.
I then ask the students to describe the types of occupations or activities in which using proper units is important. This leads the students back to the scenarios originally discussed in class and they note that using proper units is important in sports, medicine, and even zoology. I explain that the earlier they understand the importance of using proper units and converting units correctly, the easier future lab experiences will be for them. I also explain that lab answers that are improperly labeled or are missing labels will be counted as being incorrect. This seems harsh, but I have found that students only forget the labels on one assignment.
Our discussion helps to address NGSS SP4 - Analyzing and Interpreting Data - as we review the manner in which the people in each scenario failed to properly convert and examine data. This activity also addresses NGSS SP5 - Using Mathematics and Computational Thinking - as the students calculate the volume for various items.
I ask the students to remind me of the ways that we can find the mass and volume for a variety of items and I ask them to take out their flipped notes from earlier in the unit and refer back to them as necessary. This part of the lesson works best using visuals. For instance, I hold up a textbook and ask the students how we could find its mass. The students respond by telling me that we could use a balance. I then ask them how we could find the volume. Many of the students are a bit more unsure about this answer, so I remind them that they may use their notes. Looking back into their notes to find the answer helps them become more familiar with their notes and helps them become more independent instead of relying on me to supply the correct answer. The students are then able to identify that we could use a ruler and multiply the book's length x width x height to find the answer. We continue this process using items such as soda bottles, pencils, and students. While exploring the tools and methods used to find the volume and mass of the items, I continually reference the definitions of mass and volume, so the students begin to see the connection to what is actually being measured.
I then review with them the manner in which to properly use a triple beam balance, since that is what they will be using to complete the lab. For most of the students this is the first time they have used a triple beam balance as they use pan balances in sixth and seventh grade. These two lessons, Triple Beam Balance Introductory Activity and Measuring Skills: Mass, include videos and techniques for introducing the use of the triple beam balance.
The students are assigned a partner and given a mass and volume lab worksheet to complete. This worksheet is designed to have students think about the various steps involved in determining the volume of various items as well as the steps required to use a triple beam balance.
By having them answer these questions first, they have something to refer back to as they complete the measurement portion of the activity as well as a reference for later lab activities. The students must complete the front of the worksheet and show it to me prior to beginning work on the back of the worksheet. Many of the students begin working on answering the questions and soon find that they need to refer back to their notes for help in answering the questions. It is important to note that if a student asks me a question, I do not tell them the answer, but instead refer them back to their notes. I do not walk away from the student until they have the correct answer, as I stay with them to ask guiding questions to help them arrive at the correct answer. I have found that this process helps the students to work through the information at a deeper level, causing it to be more meaningful and memorable. This video provides additional details about how I question students.
In this student work sample, the student made corrections to the paper after it was graded. I explain to my students that the items we complete in class will be used and referred to throughout the year and they will be held accountable for the information on the unit assessments. By correcting the missed questions on this work sample, the student demonstrates an understanding of the importance of revision and that she is now aware of the correct answers. This also demonstrates self management of learning as discussed in the Institute for Learning's Principles for Learning.
To wrap up the lesson, I select various objects around the room and ask the students to describe the method I would use to determine the volume of the item. I select regular and irregular solids as well as various liquids. This is important because the students tend to have a difficult time remembering how to determine volume of irregular objects. I have found that the repetition of this activity helps several of the students recall the information in later lessons.