Measuring Volume of Solids and Liquids
Purpose: for students to practice measuring the volume of regular solids, irregular solids, and liquids in order to prepare for upcoming density labs
Focus Questions:
What is volume? How is it measured?
Materials:
16 Graduated cylinders
8 Aluminum blocks
8 Transparent blocks
16 Centimeter rulers or tape measures (in Blake’s room)
48 cups or containers of colored water
Colored water
Procedures:
DAY 1
1. Ask students to write a definition of volume in their notebooks. This is what they understand now. Share a couple ideas and post them using the document camera. Don’t fix or correct any of the definitions but ask the students to explain why they think this. What prior experiences have they had with volume (e.g., math and science classes)? Save the paper for later.
2. Hold up a closed box. Ask students for help measuring the volume. Someone should know to measure the length, width and height and then multiple to calculate volume. You can ask for a volunteer or two to come to the front to measure and calculate volume.
3. Ask students “If I filled this box with sand, what volume of sand would I need? Why?” Students should know that you would need almost the same volume of sand as the size of the box. It’s actually a bit less because we measured the outside of the box and the cardboard has a measurable thickness and the sand goes inside.
4. If it seems like students understand how to calculate volume, they are ready to get started calculating the volumes of the aluminum blocks and transparent plastic blocks. If not, practice as a group calculating the volume of random objects in the room.
5. Have them create a data sheet similar to this in their notebooks:
OBJECT / Length / Width / Height / VOLUMEAluminum Block
Transparent Block
6. You can organize materials by placing them in each of 8 plastic tubs. Have students work in pairs but share materials between groups of four. You can hand out the tubs or have one student from each group of four get one (i.e., designate a materials manager for each group to be responsible for getting and returning everything).
7. As students work, walk around the room to encourage all students to be involved and to measure carefully. Remind students to avoid “naked numbers.” Their numbers need to be followed by units, centimeters in this case.
8. Once students are finished and materials have been connected, compare the data for the volume. Students should be relatively close in their measurements. Ask why some numbers might be way off. What are some of the mistakes that are easy to make?
DAY 2
1. Warm-up, how do we find the volume of a box?
2. Ask “Do liquids have volume? How do we know?” Students should be getting a sense that anything that takes up space has volume. Show them the graduated cylinder and explain to them that this tool is used to measure volume of liquids. Explain to students that each of the markings on the cylinder measures 1 millileter or 1 cubic centimeter, one volume with two names. We will use cubic centimeters.
3. Demonstrate how to use the graduated cylinder by pouring some colored water into one, bending down so your eye level is even with the level of the water. Read the lowest point of the water in the center. This is called the meniscus. (Picture on page 17 of the student book – you can show with document camera.)
4. Have the students measure the volume of three cups of water. CAUTION: the food coloring will stain clothes. Students must be careful not to spill. Each person must pour and read the graduated cylinder for each color. Have them create a table like this in their notebooks:
Water / Person 1 / Person 2Red 1
Red 2
Red 3
Average Volume (calculated)
Average Volume (measured)
5. After they calculate the average, have them check their calculations by pouring all the water into one container and then redistributing it into the 3 cups. Once the water in the cups looks like it is exactly even, measure the volume and compare your measurement to the calculation you made in the table.
6. (This might be a 3rd day.) Take the Aluminum and transparent blocks from DAY 1 and measure their volume using the water displacement method. Follow these steps:
1) Pour 50 cm3 of water into the graduated cylinder
2) Put the transparent block gently in the cylinder
3) Read the new level of water
4) Subract 50 cm3, the original level of water, from the level with the transparent block in it. This is the volume of the block.
5) Compare this volume to the volume calculated from LxWxH. It should be the same or very close.
7. Review with students their original definitions of volume (using document camera). With what we know now, how can we improve our definition? Have students write a conclusion explaining what volume is and how it is measure with both liquids and solids.
(Note, this exercise does not really merit a full lab write up. They can create a table that explains how you measure volume with liquids and solids. They will add how they measure mass of liquids and solids to this table.)