jordan is doing a science fair project on the effect of music on the growth of tomatoes. he has two tomato plants, plant A and B, that he grows in a window and gives the same amount of water. plant A is exposed to classical music using headphones attached to the soil. throughout the growth period, jordan counts the number of tomatoes produced by each plant.
plant: A- 35 tomatoes
plant: B- 55 tomatoes
what is the control group?
what is the independent variable?
what is the dependent variable?
what should jordans conclusion be?
jordan needs to repeat the experiment, but his teacher says that he needs to improve his design. in his second experiment, what should he do differently?
What is the manipulated variable
Independent or manipulated Variable: classical music
Dependent variable: Number of tomatoes that grow
Controlled Variable: water and sunlight
The control group in this experiment is plant B. It is the group that is not exposed to any music and serves as a baseline for comparison.
The independent variable in this experiment is the type of music that is played to the plants. In this case, it is classical music.
The dependent variable in this experiment is the number of tomatoes produced by each plant. It is the variable that is being measured and is expected to be influenced by the independent variable.
Based on the data provided, Jordan's conclusion should be that the exposure to classical music had an effect on the growth of tomatoes. Plant A, which was exposed to classical music, produced 35 tomatoes, while plant B, the control group, produced 55 tomatoes.
In his second experiment, Jordan should make a few improvements to strengthen his design. Here are some suggestions:
1. Increase the sample size: Jordan should consider increasing the number of tomato plants he uses in each group to get a more representative result.
2. Randomize the plants: Jordan should randomly assign the plants to each group to minimize any potential bias in his experiment.
3. Replicate the experiment: It is important to repeat the experiment multiple times to check the consistency of the results and ensure their reliability.
4. Control external factors: Jordan should make sure that all other factors, apart from the independent variable (music), remain constant. This includes factors like temperature, light exposure, and humidity.
By implementing these improvements, Jordan can enhance the scientific rigor of his experiment and obtain more reliable results.
An independent variable is the potential stimulus or cause, usually directly manipulated by the experimenter, so it could also be called a manipulative variable.
A dependent variable is the response or measure of results.
Extraneous variables — other than the independent variable — potentially can affect the dependent variable, so they must be controlled. If possible, you try to keep them constant between the experimental and control group.
The experimental group receives the independent variable.
The control group is similar to experimental, except it does not receive the independent variable. Extraneous variables are balanced between experimental and control groups.
Types of experiments
1. Single blind gives the control group a placebo — a substance that is inert, it has no physical effect. Subjects don't know if they are in experimental or control group to reduce placebo effect, a change in behavior solely due to believing that you are getting the independent variable.
2. Double blind keeps both subjects and experimenter ignorant of group setup. Distribution of the independent variable and placebo are controlled by third party. This controls for experimenter bias and self-fulfilling prophecy, which means that experimenters with particular expectations are likely to consciously or unconsciously to bias the experiment and influence it to conform to their expectations.
As an example, suppose you want to find out if fluorides reduce dental cavities. You would find two groups, trying to control the extraneous variables. Extraneous variables are found by surveying previous research in the area. In this case, you would match the groups in terms of previous history of cavities, diet and dental hygiene habits including how and how often they brush their teeth.
The experimental group would get toothpaste with the independent variable, the fluoride, while the control group would not have the fluoride in their toothpaste. The toothpaste without the fluoride would be the placebo.
The dependent variable would be the number of cavities after participating in the experiment for a time. The dependent variable indicates the results, but it is not the results. At the end of the experiment, both groups could have no change in cavities or one of the groups could have a greater reduction in cavities. (Of course, if the fluoride increased cavities, you wouldn't want to use it.) All of these varied results would be indicated in terms of the dependent variable.
If only the subjects do not know who is getting the fluoride, it is a single blind experiment. If both the subjects and experimenter do not know, it is a double blind.
Control Group - Plant B
Independent Variable - Amount of water
Dependent Variable - Amount of plant growth
Conclusion - Classical music impedes the process of plant growth
What should he do differently - Think about this on your own
Can you add in another independent variable, such as controlled amount of sunlight or controlled amount of potting soil?