Measuring Volume of Liquids
Lesson 9 of 13
Objective: SWBAT measure the volume of liquids using a graduated cylinder and will create their own definition of volume.
Sometimes it's helpful for my students to be reminded of the concepts we have previously learned. In this case, we talked about volume in the previous lesson while learning how to measure the volume of regular solids. To start this lesson, I want them to recall what volume is and how to measure it when dealing with a solid object. To do this, I have them complete the following statements in their notes sheet:
Volume is a measurement of…
How do you find the volume of regular objects (list the steps below)?
How do you suppose we measure the volume of the water inside the cup? (There is a cup of colored water on everyone's table in order to get them thinking about the properties of liquids.)
After 3-4 minutes, I solicit responses from the students to share out as a class.
Now, I give every table a graduated cylinder. We spend about one minute making observations. I keep prompting (Is there something more? Can you find something we haven't noticed?) until students have noted that it has numbers on the side, it says mL, it can hold liquids.
I then, without giving instructions, ask the children to find the volume (or how much space it takes up) of the liquid in the cup. As they explore, they write responses to the following prompt in their notes:
Using the tool on your table, find the volume of the liquid inside the cup. Write your measurement below and the steps you took to find it.
Volume of the liquid =
We found the volume by…
If a group was able to successfully find the volume of the liquid using the graduated cylinder, I ask them to share out their responses with the class. I also write down their steps onto the SMARTBoard or whiteboard to use for the next section of the lesson.
If no one has the correct measurement, I ask them what they tried and why they think it didn't work. Then, I will walk them through the steps. I ask that they write the steps in the EXPLAIN section of their notes as a reference for how to use a graduated cylinder in the future.
1. Pour the liquid into the graduated cylinder.
2. Make sure your eyes are level with the water level.
3. Find the meniscus (bubble on the surface of the water) and read the line BELOW it.
4. Write down your measurement in mL.
Now that the students have the procedure for finding the volume of liquids, I give them an opportunity to practice reading the graduated cylinders.
I place 5-10 cylinders around the room in various spots (on top of shelves, next to the pencil sharpener, on my desk, etc). The students read the measurements and record them in their notes.
The kids move around with clipboards or their notebooks. I usually have them do this in complete silence and on their own, however, I have paired students who I know will struggle with the task.
TIPS: Make sure to label the containers! I put food coloring in the water to make the meniscus easier to see. Direct students where to start so they don't all clump up. You can do this by having them count off by the number of graduated cylinders, and then have all "ones" start at cylinder 1, all "twos" start at cylinder 2, etc.
After students have practice with finding the volume of liquids, my goal is to have them connect yesterday's lesson to today's. I want them to make the remember volume as being a measurement of how much space something takes up. To do this, they answer the following prompt in their notes:
List one similarity and one difference between measuring the volume of liquid and measuring the volume of a regular solid.
My expectation is that students identify the similarity in the measurement of solids and liquids is that both measurements are of volume or how much space it takes up. A difference is in the method of measurement (go on to explain the various methods).
This helps students to construct a deeper meaning of volume and connect it to another substance. It also helps them to identify connections between lessons.