Chemistry (CHEM253) Density Laboratory
Vocabulary: buoyancy, density, graduated cylinder, mass, matter, scale, volume Prior Knowledge Questions (Do these BEFORE using the Gizmo.) [Note: The purpose of these questions is to activate prior knowledge and get students thinking. Students are not exp...
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get students thinking.
Students are not expected to know the answers to the Prior Knowledge Questions.]
1. Of the objects below, circle the ones you think would float in water. Predictions will vary.
Correct answers are shown:
2. Why do some objects float, while others sink?
Answers will vary. [An object floats when the weight of the liquid it displaces is equal to the
weight of the object. Objects sink when they are heavier than the equivalent volume of
liquid. In other words, objects sink when they are denser than the liquid.]
Gizmo Warm-up
The Density Laboratory Gizmo™ allows you to measure a variety of
objects, then drop them in water (or other liquid) to see if they sink or float.
1. An object’s mass is the amount of matter it contains. The mass of an
object can be measured with a calibrated scale like the one shown in
the Gizmo. Drag the first object onto the Scale. (This is object 1.)
What is the mass of object 1? 19.5 grams (19.5 g)
2. An object’s volume is the amount of space it takes up. The volume of
an irregular object can be measured by how much water it displaces in
a graduated cylinder. Place object 1 into the Graduated cylinder.
What is the volume of object 1? 14.0 cm3 (equivalent to 14.0 mL)
Note: While milliliters (mL) are used to measure liquid volumes, the equivalent unit cubic
centimeters (cm3) are used for solids. Therefore, write the volume of object 1 in cm3.
3. Drag object 1 into the Beaker of liquid. Does it sink or float? It sinks.
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, 8/20/23, 6:32 PM 446939196 396035520 Density Lab SE Key pdf
Get the Gizmo ready:
Activity A:
Drag object 1 back to the shelf.
Float or sink?
Check that Liquid density is set to 1.0 g/mL.
Question: How can you predict whether an object will float or sink?
1. Observe: Experiment with the different objects in the Gizmo. Try to determine what the
floating objects have in common and what the sinking objects have in common.
2. Form hypothesis: Compare the floating objects, then do the same for the sinking objects.
A. What do the floating objects have in common? Answers will vary.
B. What do the sinking objects have in common? Answers will vary.
3. Collect data: Measure the mass and volume of objects 1 through 12, and record whether
they float or sink in the table below. Leave the last column blank for now.
Density
Object Mass (g) Volume (cm3) Float or sink?
(g/cm3)
1 19.5 g 14.0 cm3 Sink 1.39 g/cm3
3
2 11.0 g 9.0 cm Sink 1.22 g/cm3
3
3 4.0 g 5.0 cm Float 0.80 g/cm3
3
4 135.0 g 7.0 cm Sink 19.29 g/cm3
5 4.0 g 3.5 cm3 Sink 1.14 g/cm3
6 78.0 g 29.0 cm3 Sink 2.69 g/cm3
7 2.0 g 21.0 cm3 Float 0.10 g/cm3
3
8 24.0 g 26.0 cm Float 0.92 g/cm3
3
9 99.0 g 44.0 cm Sink 2.25 g/cm3
3
10 42.0 g 61.0 cm Float 0.69 g/cm3
3
11 65.0 g 40.0 cm Sink 1.63 g/cm3
12 104.0 g 114.0 cm3 Float 0.91 g/cm3
(Activity A continued on next page)
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