After we are done with the volume of regular objects lab, we will determine volume using water displacement. This is a lab where setting up the equipment on a lunch tray really comes in handy, its pretty messy! Whenever we use water, I always add a few drops of blue or green food coloring to it. The food coloring makes its easier to read the water levels in the graduated cylinders. Yellow is light, and red tends to stain more than the other colors. I use a large beaker as my stock of colored water then fill smaller beakers with it. A few drops per 100 mL is plenty.
This will be a stations lab with 10 stations. On each tray, there will be a beaker (200 - 250 mL) of colored water, graduated cylinders (10 mL, 25 mL, and 50 mL), two items to measure (rocks, small rubber stoppers, marbles, pennies, etc..) and a plastic spoon. The plastic spoon is a must have for this lab. How so? Lets say the kids are finding the volume of a small rock, they drop the rock into the graduated cylinder, find the volume, now they have to get it out. I show them how to tilt the graduated cylinder to pour the water back into the beaker while using the spoon to cover the opening of the graduated cylinder. Water pours out while the rock is stopped by the spoon. They can easily take the rock and place it back on the lunch tray.
If that doesn't work, and the rock (or whatever object they are finding the volume for) falls into the beaker, they can use the spoon to fish out the rock from the bottom of the beaker. Otherwise, the kids are putting their whole hand into the beaker to fish out the rock and their hand will displace the water in the beaker = spills. Another reason to use the spoon is that some objects, like metal cylinders or marbles, can crack the beaker when it falls out of the graduated cylinder. (also, to prevent the grad. cylinder from breaking when an object is placed in it, place a small rubber stopper inside the grad. cylinder)
I usually remind the students that when they fill up the graduated cylinders to only fill it about half way with water. This allows room for the object to be placed into the graduated cylinder without the water running over. I also remind them to record the starting volume, drop the object in, record the final volume, and to subtract the final volume from the stating volume to calculate the volume of the object. (1 mL = 1 cubic cm)
Prior to starting the lab, we will talk about Archimedes, how to read a graduated cylinder, what a meniscus is, what displacement is and how to use it to calculate volume, and how to determine the increments to read the volume. We will also do a few practice problems as a pre-lab.
This will be a stations lab with 10 stations. On each tray, there will be a beaker (200 - 250 mL) of colored water, graduated cylinders (10 mL, 25 mL, and 50 mL), two items to measure (rocks, small rubber stoppers, marbles, pennies, etc..) and a plastic spoon. The plastic spoon is a must have for this lab. How so? Lets say the kids are finding the volume of a small rock, they drop the rock into the graduated cylinder, find the volume, now they have to get it out. I show them how to tilt the graduated cylinder to pour the water back into the beaker while using the spoon to cover the opening of the graduated cylinder. Water pours out while the rock is stopped by the spoon. They can easily take the rock and place it back on the lunch tray.
If that doesn't work, and the rock (or whatever object they are finding the volume for) falls into the beaker, they can use the spoon to fish out the rock from the bottom of the beaker. Otherwise, the kids are putting their whole hand into the beaker to fish out the rock and their hand will displace the water in the beaker = spills. Another reason to use the spoon is that some objects, like metal cylinders or marbles, can crack the beaker when it falls out of the graduated cylinder. (also, to prevent the grad. cylinder from breaking when an object is placed in it, place a small rubber stopper inside the grad. cylinder)
I usually remind the students that when they fill up the graduated cylinders to only fill it about half way with water. This allows room for the object to be placed into the graduated cylinder without the water running over. I also remind them to record the starting volume, drop the object in, record the final volume, and to subtract the final volume from the stating volume to calculate the volume of the object. (1 mL = 1 cubic cm)
Prior to starting the lab, we will talk about Archimedes, how to read a graduated cylinder, what a meniscus is, what displacement is and how to use it to calculate volume, and how to determine the increments to read the volume. We will also do a few practice problems as a pre-lab.
Left Side:
Right Side:
- Practice: Reading a Graduated Cylinder and determining volume by displacement (page 1)
Posts
Wow! This lesson with attached worksheets is so helpful! It is really saving me time when planning my unit on Fluids, Forces, and Density for my Grade 7,8 Science class. Thank you very much for sharing your hard work! It is much appreciated.
ReplyDelete-Leanne, Saskatchewan
Love your website! You seem like a great teacher! I am using all of your stuff. :) Thanks so much. I am a first year teacher and am really struggling to find interesting materials. I am so excited to use this today in my classroom!
ReplyDelete