Question

Andrew arrived at school and went directly to his earth science class. He took off his cap and coat and sat down at his desk. His teacher gave him a large rock and asked him to find its density. Realizing that the rock was too large to work with, Andrew got a hammer from the supply cabinet and hit the rock several times until he broke off a chip small enough to work with. He partly filled a graduated cylinder with water and suspended the rock in the water. The water level rose 2 cm. Andrew committed this measurement to memory. He next weighed the rock on a balance. The rock weighed 4 oz. Andrew then calculated the density of the rock as follows: He divided 2 cm by 4 oz. He then reported to his teacher that the density of the rock was 5 cm/oz.

(A) Andrew measured the density correctly.
(B) Andrew should have used different units for the measurements.
(C) Andrew's calculation was accurate.
(D) Andrew should have used a different method to find density.

Answer 1

Andrew measured the density incorrectly.
He should have divided the mass (4 oz) by the volume (2 cm) to find the correct density.

Answer 2

Andrew measured the density correctly by dividing the change in water level by the mass of the rock. The units for density should be cm/oz.

Step-by-step explanation:

Andrew measured the density correctly. The density of an object is determined by dividing its mass by its volume. In this case, Andrew divided the change in water level (2 cm) by the mass of the rock (4 oz). Therefore, the units for density should be cm/oz.