ANSWER SHEET AND EXPLANATION FOR PROBLEMS 1-10…REVIEW THE ANSWERS AND MAKE
SURE YOU UNDERSTAND!!!
1. Correct Answer: C — Object X, object Y, object Z.
Explanation: Object X has the lowest density because it floats highest in the liquid. Object Z has the highest density because it is
the only object that sank in the liquid. Object Y floats low in the liquid, indicating a density slightly lower than the density of the
liquid.
2. Correct Answer: C — it has a high density
Explanation: Objects sink when their density is greater than the density of water. Mass alone or volume alone are not enough to
determine density. For example, a cruise ship has an enormous mass and a very large volume, but it is able to float because its
density is less than the density of water.
3. Correct Answer: B — 2.4 g/cc
Explanation: Density is calculated as mass divided by volume. 33.6 g/14.0 mL = 2.4 g/mL.
4. Correct Answer: C — 0.9 g/mL
Explanation: Object X has a density of 1.04 g/cc, object Y has a density of 0.85 g/cc, and object Z has a density of 0.96 g/cc. An
object less dense than the liquid will float, and an object more dense than the liquid will sink. Object Y floats, so the liquid is
more dense than 0.85 g/cc. Object Z sinks, so the liquid is less dense than 0.96 g/cc. Therefore, the only possible choice for
density is 0.9 g/mL. (Recall that one cubic centimeter (cc) is equivalent to one milliliter (mL).)
5. Correct Answer: A — 0.88 g/cc
Explanation: Like object 3 in the Gizmo, an iceberg floats very low in the water. This means that its density is slightly less than
the density of seawater. An object with a density of 0.23 g/cc will float much higher in the water. An object with a density greater
than 1.03 g/cc would sink. Therefore the most likely density of the iceberg is 0.88 g/cc.
6. Correct Answer: C — It will sink in Beaker 1 and float in Beaker 2.
Explanation: Objects sink in liquids that are less dense than the object itself. They float in liquids that have a greater density. The
density of the liquid in Beaker 1 is 0.5 g/cc, which is lower than the density of the object, so the object will sink in Beaker 1. The
density of the liquid in Beaker 2 is 1 g/cc, which is greater than the density of the object, so the object will float in Beaker 2.
7. Correct Answer: B — Density of object 1 = 3.0 g/cc
Density of object 2 = 1.8 g/cc
Explanation: For an object to float, the density of the object must be less than the density of the liquid. Therefore, the density of
both of these objects must be less than 3.2 g/cc. This allows you to eliminate answer choices A and D. Objects of lower density
float in a higher position than objects of higher density. Because object 2 is floating in a higher position than object 1, its density
must be lower than that of object 1. Answer B is the only answer that meets all of these conditions.
8. Correct Answer: D — The liquid in Beaker B has a greater density than the liquid in Beaker A.
Explanation: For an object to float, the liquid must have a greater density than the object. Therefore, both liquids must have a
greater density than the identical objects referred to here. This allows you to eliminate answers A and B. Also, an object floats in a
higher position in a liquid of higher density. Therefore the liquid in Beaker B must have a higher density than the liquid in
Beaker A. Answer D is the only answer that satisfies both of these conditions.
9. Correct Answer: B — Density of object 1 = 3.0 g/cc
Density of object 2 = 0.8 g/cc
Explanation: For an object to float, it must be less dense than the liquid it is in. Therefore, the density of object 2 must be less than
2.0 g/cc, which is the density of the liquid. This allows you to eliminate answer choices A and C. An object sinks when it has a
greater density than the liquid into which it is placed. Therefore, the density of object 1 must be greater than 2.0 g/cc, eliminating
answer D. Answer B is the only answer that satisfies both of these conditions.
10. Correct Answer: D — The object's density is greater than 2.0 g/cc
Explanation: Because the object sinks in Beaker 1 and Beaker 2, it must be more dense than the liquid in either beaker.
For problems 11-13 … use what you have learned in lab (both real and virtual) to solve these
problems. Call on a classmate, parent, Mr. David, or a higher power to make sure you understand !!
Check your answers with a classmate before the quiz.
BrainPOP Measuring Matter #1-10 – watch the BrainPOP video again if you are struggling with these
problems. The instructions to access BrainPOP are on the Science blog post. Again, make sure you
check your answers with a friend before the quiz!!