Exercise 3: Calculate the density of an object
In this exercise, you will be performing an experiment with the scenario outlined in Exercise 2.
For this experiment you will need to collect the following items:
- An irregularly shaped object that floats (e.g. an apple, a piece of wood)
- A clear container
- Ensure the walls are perpendicular to the bottom of the container
- The container should be able to fit your object completely but ideally it is not too much larger than the object.
- A ruler/measuring tape
- Tape (or some other method to make markings on your container such as a marker)
- A thin object (e.g. a utensil)
Procedure:
Before you begin, you will need to take a few measurements of the container that will be used later on. Take the measurements needed to calculate the area of the top of your container. For example, if your container is rectangular, measure the width and the length. If it is cylindrical, measure the diameter. This will be referred to as the base of your container.
Now, fill your container about halfway with water. Mark the water level on your container using tape. Note: Be consistent with which side of the tape you measure the water level at.
Next, place your object in the water, and let it float naturally. Measure the new water level with a new piece of tape.
Lastly, take a thin object (such as a utensil) to fully submerge your object. Measure this final water level with another piece of tape. It may be easier to do this step with a partner, so the object can remain fully submerged.
Exercise 3.1 (2 marks)
Provide a picture of your experimental set-up that clearly shows the container, the object, and the student card(s) of the participating member(s) in this lab.
Secondly, provide an additional image of the student card(s) used in the previous photo. Here, the student name(s) and student number(s) must be legible. With your experimental set up in the background, you may take this image from a closer view to ensure the student card(s) is/are in full focus. Note: you do not need to be in the photo. If you are completing this lab with others virtually, you may provide a screenshot of your video call, with the student cards of all members visible. Your experimental set up must still be visible in the background.
Results
Use the table below to record the water level data for when no object is present, when the object is floating, and when the object is submerged. Repeat these measurements three times and then take the average for each quantity.
The link to download the Excel file that you may use for this lab is found below.
Calculate the object’s volume
You can now calculate the volume of the object using the change in water level. Take the change in height between the water level with no object and the water level with a submerged object.
Now multiply this change in height by the base. This will provide you with a volume measurement that will correspond to the volume of your apple.
Calculate the volume displaced
Using a similar method as above, calculate the volume of the water displaced. The only difference now is that you should now use the change in height of the water level with no object and the water level with your floating object.
Exercise 3.2 (2 marks)
Find the object’s density
Exercise 3.3 (3 marks)
Using the equation you derived in Exercise 2.3, report the density of your object. Considering that the density of water is 1000 kg/m3, does the density value that you calculated make sense? Briefly explain why or why not. Upload your solution to Crowdmark.
Before you continue!
Before continuing, be sure you have completed Exercises 3.1-3.3, which will be graded and submitted through Crowdmark.
