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? A control variable is a test group that does not receive the independent variable.
1. 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.
2. Using your bar graph, determine if the average number of drops for each group is about the 3. same. List four reasons why the actual number of drops for each group was similar or dissimilar.
3. Are the results of this experiment “valid”? Why or why not?
4. 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?
1. No, there is no control group present in this experiment because there is no test group that does not receive the independent variable. In this case, the independent variable is the number of drops of water and it is being tested on the "Lincoln" side of the penny.
2. Without the actual bar graph provided in the question, it is not possible to determine if the average number of drops for each group is about the same. However, reasons why the actual number of drops for each group may be similar or dissimilar could include the consistency in drop size, the angle at which the penny is held, the temperature of the water, or the cleanliness of the penny.
3. The results of this experiment may be considered valid if it adheres to the principles of a valid experimental procedure. This would include clear documentation of the variables being tested, consistent and controlled conditions, and accurate measurement and recording of data.
4. If the other side of the penny was used, the results of the experiment would not be comparable to the rest of the class because the "Lincoln" side of the penny was the focus of the experiment. Using the same side of the penny ensures consistency and allows for accurate comparison and analysis of data among all participants.
1. No, there is no control group present in this particular experiment. A control group is a group that does not receive the independent variable being tested. In this experiment, the independent variable is the number of drops of water, and there is no group that does not receive any drops of water.
2. Since no bar graph is provided in the question, we cannot determine the average number of drops for each group. However, here are four possible reasons why the actual number of drops for each group could be similar or dissimilar:
a) Variation in the size of the drops: If some drops are bigger or smaller than others, it could impact the number of drops that can fit on the penny.
b) Precision of the dropper: If the dropper used to release the drops is not consistent in terms of the amount released each time, it could affect the number of drops on the penny.
c) Variation in the surface tension of the water: If the surface tension of the water differs between drops, it could affect how they spread and stack on the penny.
d) Variation in drop placement: If the drops are placed differently on the penny within each group, it could result in different numbers of drops.
3. The results of this experiment cannot be determined as "valid" based on the information provided. The validity of an experiment depends on various factors, including the reliability of the data collected, the control of variables, and the adherence to appropriate experimental procedures. Without more details about the experimental procedure and data collection, it is impossible to determine the validity of the results.
4. If the other side of the penny was used, it could potentially have a different surface or texture compared to the "Lincoln" side. This difference could impact the number of drops that can fit on the penny. To ensure consistent and comparable data, it is important for all participants to use the same side of the penny (in this case, the "Lincoln" side). Using different sides would introduce additional variables and make it difficult to compare data accurately.