AZSCI Scale, Proportion, and Quantity 2

Question 1

A scientist is comparing the size of a virus (about 100 nm) to a human cell (about 10 µm). Approximately how many times larger is the human cell than the virus?

Accepted Answer

100 times larger

Answer

10 µm = 10,000 nm; 10,000 nm ÷ 100 nm = 100, so the human cell is 100 times larger than the virus.

Question 2

A car travels 300 km in 3 hours at a constant speed. What is the proportional relationship between distance and time?

Accepted Answer

100 km per hour

Answer

300 km ÷ 3 hours = 100 km/hour; this constant ratio represents a directly proportional relationship.

Question 3

Which tool would a scientist use to accurately measure the mass of a small rock sample?

Accepted Answer

Balance scale or digital balance

Answer

Mass is measured using a balance or digital balance, which detects or compares the gravitational force on an object.

Question 4

In an experiment, doubling the concentration of a reactant doubles the reaction rate. This relationship is best described as:

Accepted Answer

Directly proportional

Answer

When one quantity doubles and the other doubles as well, they share a directly proportional (linear) relationship.

Question 5

What is the primary reason scientists worldwide use the International System of Units (SI)?

Accepted Answer

To ensure measurements are consistent and comparable across labs and countries

Answer

Standard SI units ensure that measurements can be reliably reproduced and compared by scientists anywhere in the world.

(AZSCI) Arizona Science Test Practice Test

(AZSCI) Arizona Science Test Practice Test

AZSCI Scale, Proportion, and Quantity 2