Question

Propellants are chemicals used to power rockets, much like gas is used to power cars. A rocket scientist has been using Propellant X in her rockets for many years, but is interested to see if Propellant Z will cause her rockets to rise higher into the air. The scientist builds a rocket that uses Propellant Z. A proper control for the experiment would be an identical rocket that uses which of the following?

a) Propellant X
b) Propellant Y
c) A mix of Propellant X and Z
d) No propellant at all

Answer 1

The proper control in an experiment to compare the effectiveness of rocket propellants is an identical rocket using Propellant X, as this is the standard being compared against.

Step-by-step explanation:

In the context of an experiment comparing the effectiveness of different rocket propellants, the objective is to determine if Propellant Z will cause rockets to rise higher than when using Propellant X. To establish a proper control, the scientist should use an identical rocket that uses Propellant X as the propellant. This is because Propellant X is the known standard to which the new propellant is being compared. Propellants initiate a chemical reaction that releases gases to create thrust, propelling the rocket upward.

Using a mix of both propellants or no propellant would not provide a valid comparator. A mix would create an entirely different reaction (with unknown properties), and a rocket without any propellant wouldn't demonstrate the effect of the propellant at all. So, the proper control for the experiment is an identical rocket that uses Propellant X, ensuring that any difference in the height achieved by the rockets is due to the propellant used.