Question

In all science experiments, scientists are testing the result of what happens when they change one part of the experiment. These parts of the experiment are called variables.

Independent Variable: The part of the experiment that is intentionally changed.
Dependent Variable: The part of the experiment that is being measured based on what is intentionally changed (the independent variable).
Controlled Variable(s): All other parts of the experiment that stay the same.

EXAMPLES:


***Read through the Lab Report below, then identify each variable- independent, dependent, control(s).
Lab Report: How Air Dryness Affects Ice Sublimation
Purpose: The purpose of this experiment is to test how different environmental conditions — specifically air dryness (humidity) — affect how quickly ice sublimates (changes directly from a solid to a gas).
Background Information: Sublimation occurs when a solid turns directly into a gas without first becoming a liquid.
Hypothesis: If air is drier, then ice will sublimate faster, because the water molecules escape into the air more easily.
Materials:
4 small ice cubes
4 small bowls
Humidity control materials:
Dry air environment (with silica gel)
Moderate humidity environment (normal room air)
High humidity environment (covered with damp cloth)
Moving air environment (fan to move air)


Timer or clock
Scale ( to measure ice mass before and after)
Hygrometer ( to measure humidity)
Notebook for recording data
Procedure:
Label each dish according to its humidity condition:
Dry Air
Moderate Humidity
High Humidity
Moving Air (dry)
Place one ice cube that is the same size and mass in each bowl.
Start the timer.
Every 2 hours, observe and record:
Ice appearance (shrinking, melting, or disappearing)
Any liquid water present
Humidity
Continue observations for 24 hours or until ice disappears completely.
Record the time when each ice cube has fully sublimated or melted.
Data Table:
Humidity Condition
Time it takes for Ice to Sublimate (hours)
Observations
Dry Air
24
Ice slowly disappears without melting
Moderate Humidity
36
Ice shrinks slowly, some melting
High Humidity
48
Ice melts mostly rather than sublimates
Moving Air (Dry)
18
Ice disappears fastest due to airflow

Results:
Dry air: Ice sublimates steadily, little liquid forms.
Moderate humidity: Sublimation occurs, but slower.
High humidity: Very little sublimation; ice mostly melts if temperature allows.
Moving air (dry): Ice sublimates fastest due to airflow removing water vapor.
Conclusion: The experiment shows that air dryness affects the rate of ice sublimation. Ice sublimates faster in dry air and even faster when the air is moving. High humidity makes sublimation much slower. The hypothesis was correct in that lower humidity increases sublimation speed.

What is the dependent variable in this experiment (2 pts)? Hint- this is the variable that is being measured based on what is intentionally changed

Answer 1

Dependent variable: The time it takes for the ice to sublimate (i.e., the rate/amount of ice lost measured over time).