A class is to perform an experiment to study the effects of various plant foods on a type of indoor plant.The teacher provides three similar plants,a water supply,and three different packets of plant food.Explain how you might conduct a controlled experiment.
Wouldn't you use only one type of food on one plant consistently?
Sra
The plant food is the independent variable, probably the amount of growth during a specified period is the dependent variable, and the amount of water is one extraneous variable. Another extraneous variable would be the amount of sunlight each plant gets. As a better control, it would be good to have a fourth plant that gets no plant food.
A review of the experimental method might be helpful.
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.
I hope this helps a little more. Thanks for asking.
To conduct a controlled experiment on the effects of various plant foods on a type of indoor plant, you can follow these steps:
1. Start with three similar plants: Use three identical indoor plants of the same species, size, and health. This ensures that any differences observed in plant growth and health can be attributed to the plant food being tested rather than variations in plant characteristics.
2. Identify the variables: The independent variable is the type of plant food, and the dependent variable is the growth and health of the indoor plants. Other variables, such as the amount of water and light, should be kept constant throughout the experiment to eliminate their influence on the results.
3. Assign treatments: Divide the three plants into three groups and assign each group a specific treatment. For example, Group A can be the control group where the plant is only watered regularly, Group B can be treated with plant food packet 1, and Group C can be treated with plant food packet 2.
4. Determine the dosage: Follow the instructions on the plant food packets to determine the appropriate dosage for each treatment group. Ensure that the plants receive equal amounts of water throughout the experiment.
5. Record observations: Monitor the growth and health of the plants over an established period of time. Take regular measurements, such as plant height, number of leaves, leaf color, or overall plant appearance. Document these observations in a table or a journal.
6. Analyze data: At the end of the experiment, analyze the data collected. Compare the growth and health of the plants in each treatment group to identify any differences. Use statistical analysis, such as calculating averages and standard deviations, to determine the significance of these differences.
7. Draw conclusions: Based on the data analysis, draw conclusions about the effects of different plant foods on the indoor plant. Determine if any specific plant food has a significant impact on the growth and health of the plants.
By conducting a controlled experiment with identical plants and carefully controlling all variables except for the independent variable (the plant food), you can ensure that any observed effects can be attributed to the plant food being tested.