PURPOSE: In this activity, you will practice graphing the results of an experiment. You will also learn what constitutes a valid experimental procedure.

PROBLEM: How many drops of water will fit onto the “Lincoln” side of a penny?
PREDICTION (Hypothesis): I predict that ____ drops of water will fit on the head side of a penny.

A constant is things in an experiment that are kept the same in all trials.

In this experiment, there were a limited number of constants. Name two of them.

An independent variable is changed on purpose by the experimenter.

What was the independent variable in this experiment?
Where is the independent variable located on a graph?

A dependent variable is a variable that responds to the independent variable.

What was the dependent variable in this experiment?
Where is the dependent variable located on a graph?

A control variable is a test group that does not receive the independent variable.

Based on this experiment, is there a control group present? If so, what is it?

Validity is a measure of how correct the results of an experiment are. Think about what makes an experiment valid.

Using your bar graph, determine if the average number of drops for each group is about the same. List four reasons why the actual number of drops for each group was similar or dissimilar.
Are the results of this experiment “valid”? Why or why not?
What would happen if you used the other side of the penny? When comparing data with the rest of the class, why would it be important that we all use the same “Lincoln” side of the penny?

In this experiment, the constants could be the type of penny used (all pennies are the same), the surface of the penny (all pennies have the same texture), etc.

The independent variable in this experiment is the number of drops of water.

On a graph, the independent variable is usually located on the x-axis.

The dependent variable in this experiment is the number of drops of water that fit on the "Lincoln" side of the penny.

On a graph, the dependent variable is usually located on the y-axis.

Based on the given information, it is not mentioned whether there was a control group present in this experiment.

Validity in an experiment is determined by following proper experimental procedures, conducting multiple trials, and ensuring that the variables are properly controlled.

To determine if the average number of drops for each group is about the same, one can compare the bar heights on the graph.

The reasons why the actual number of drops for each group may be similar or dissimilar could be due to slight variations in surface tension, differences in drop size, inconsistencies in the penny's surface, or human error.

It is not mentioned whether the results of this experiment are "valid" based on the given information.

If the other side of the penny was used, the results would not be comparable to the rest of the class because they were all using the "Lincoln" side of the penny. It is important to use the same side of the penny to ensure consistency and comparability of data.

Two constants in this experiment could be the type of penny used and the temperature of the water.

The independent variable in this experiment is the number of drops of water.

The independent variable is typically plotted on the x-axis of a graph.

The dependent variable in this experiment is the number of drops of water that fit on the "Lincoln" side of the penny.

The dependent variable is typically plotted on the y-axis of a graph.

Based on the information provided, it is unclear if there is a control group in this experiment.

Validity in an experiment refers to how accurately the results reflect the relationship between the variables being studied. It is not clear from the information provided whether the experiment was conducted in a way that ensures validity.

To determine if the average number of drops for each group is about the same, you can compare the heights of the bars on the bar graph.

Reasons why the actual number of drops for each group may be similar or dissimilar could include differences in the amount of water on the penny, variations in the dropper used, inconsistencies in counting the drops, and individual differences in technique.

Based on the information provided, it is not possible to determine if the results of this experiment are valid as there is no information about the experimental procedure, data collection, or analysis.

If you used the other side of the penny, you would be measuring the number of drops of water that fit on the opposite side. It would be important for all participants to use the same "Lincoln" side of the penny to ensure consistency and comparability of the data collected.