Experimental Design |
Vocabulary and Essential Understandings
A hypothesis is a prediction about the relationship between variables. A hypothesis is an educated guess/prediction about what will happen based on what you already know and what you have already learned from your research. It must be worded so that it is “testable.”
In order to conduct an experiment, one must recognize all of the potential variables or changes that can affect its outcome.
An independent variable is the factor in an experiment that is altered by the experimenter. The independent variable is purposely changed or manipulated.
A dependent variable is the factor in an experiment that changes as a result of the manipulation of the independent variable.
The constants in an experiment are those things that are purposefully not changed and remain the same throughout the experiment.
In science, it is important that experiments and the observations recorded are repeatable.
There are two different types of data – qualitative and quantitative. Qualitative data deal with descriptions and data that can be observed, but not measured. Quantitative data are data that can be counted or measured and the results can be recorded using numbers. Quantitative data can be represented visually in graphs and charts. Quantitative data defines whereas qualitative data describes. Quantitative data are more valuable in science because they allow direct comparisons between observations made by different people or at different times.
Independent Variables vs. Constant Variables
Example #1
Saul and Haileigh were conducting an experiment. They wanted to know which glue was the best. They bought four different types of glue. Saul cut 4 stars and glued one star on a piece of white paper. For each star, they used a different type of glue. Each time they used 5 ml of glue.
Read the statements below. Tell if the statement is a constant or an independent variable.
1. Saul cut 4 stars out of the same paper and glued them on 4 pieces of the same kind of white paper.
2. For each star, they used a different type of glue.
3. Each time they used 5 ml of glue.
Example #2
Leontre and Amber were conducting an investigation to understand how leaves affect the process of photosynthesis. They each planted a bean seed in the same kind of soil and in the same type of cups. Leontre was responsible for plant #1. He watered his plant every other day with ¼ of a cup of water. Amber was responsible for plant #2. She watered her plant every other day with ¼ of a cup of water. As her plant grew, she cut off the leaves. After 10 days they compared their plants to see if the plant grew at the same rate.
Read the statements below. Tell if the statement is a constant or an independent variable.
4. They each planted a bean seed in the same kind of soil in separate cups.
5. They watered their plants every other day with ¼ of a cup of water.
6. As Amber’s plant grew, she cut off the leaves.
Observation
An observation is what you see, feel, taste, hear, or smell in an experiment.
Inference
An inference is a tentative explanation based on background knowledge and available data.
Prediction
A prediction tells what may happen in some future situation. It is based on the application of scientific principles and factual information.
Conclusions
Conclusions are drawn by making judgments after considering all the information you have gathered. Conclusions are based on details and facts.
Elapsed Time
Elapsed time is the amount of time that has passed between two given times.
Experiment
An experiment is a fair test driven by a hypothesis. A fair test is one in which only one variable is compared.
Hypothesis
A hypothesis is an educated guess/prediction about what will happen based on what you already know and what you have already learned from
your research. It must be worded so that it is “testable.”
Independent Variable
An independent variable is a factor in an experiment that is altered by the experimenter; it is purposely changed or manipulated.
Dependent Variable
A dependent variable is the factor in an experiment that changes as a result of the manipulation of the independent variable.
Constants
Constants are those things in an experiment that are purposefully not changed and remain the same throughout the experiment.
Quantitative Data
Quantitative data are data that can be counted or measured and the results can be recorded using numbers.
Qualitative Data
Qualitative data are data that deals with descriptions and data that can be observed.
Celsius Thermometer
A Celsius thermometer is used to measure temperature in degrees Celsius.
A hypothesis is a prediction about the relationship between variables. A hypothesis is an educated guess/prediction about what will happen based on what you already know and what you have already learned from your research. It must be worded so that it is “testable.”
In order to conduct an experiment, one must recognize all of the potential variables or changes that can affect its outcome.
An independent variable is the factor in an experiment that is altered by the experimenter. The independent variable is purposely changed or manipulated.
A dependent variable is the factor in an experiment that changes as a result of the manipulation of the independent variable.
The constants in an experiment are those things that are purposefully not changed and remain the same throughout the experiment.
In science, it is important that experiments and the observations recorded are repeatable.
There are two different types of data – qualitative and quantitative. Qualitative data deal with descriptions and data that can be observed, but not measured. Quantitative data are data that can be counted or measured and the results can be recorded using numbers. Quantitative data can be represented visually in graphs and charts. Quantitative data defines whereas qualitative data describes. Quantitative data are more valuable in science because they allow direct comparisons between observations made by different people or at different times.
Independent Variables vs. Constant Variables
Example #1
Saul and Haileigh were conducting an experiment. They wanted to know which glue was the best. They bought four different types of glue. Saul cut 4 stars and glued one star on a piece of white paper. For each star, they used a different type of glue. Each time they used 5 ml of glue.
Read the statements below. Tell if the statement is a constant or an independent variable.
1. Saul cut 4 stars out of the same paper and glued them on 4 pieces of the same kind of white paper.
2. For each star, they used a different type of glue.
3. Each time they used 5 ml of glue.
Example #2
Leontre and Amber were conducting an investigation to understand how leaves affect the process of photosynthesis. They each planted a bean seed in the same kind of soil and in the same type of cups. Leontre was responsible for plant #1. He watered his plant every other day with ¼ of a cup of water. Amber was responsible for plant #2. She watered her plant every other day with ¼ of a cup of water. As her plant grew, she cut off the leaves. After 10 days they compared their plants to see if the plant grew at the same rate.
Read the statements below. Tell if the statement is a constant or an independent variable.
4. They each planted a bean seed in the same kind of soil in separate cups.
5. They watered their plants every other day with ¼ of a cup of water.
6. As Amber’s plant grew, she cut off the leaves.
Observation
An observation is what you see, feel, taste, hear, or smell in an experiment.
Inference
An inference is a tentative explanation based on background knowledge and available data.
Prediction
A prediction tells what may happen in some future situation. It is based on the application of scientific principles and factual information.
Conclusions
Conclusions are drawn by making judgments after considering all the information you have gathered. Conclusions are based on details and facts.
Elapsed Time
Elapsed time is the amount of time that has passed between two given times.
Experiment
An experiment is a fair test driven by a hypothesis. A fair test is one in which only one variable is compared.
Hypothesis
A hypothesis is an educated guess/prediction about what will happen based on what you already know and what you have already learned from
your research. It must be worded so that it is “testable.”
Independent Variable
An independent variable is a factor in an experiment that is altered by the experimenter; it is purposely changed or manipulated.
Dependent Variable
A dependent variable is the factor in an experiment that changes as a result of the manipulation of the independent variable.
Constants
Constants are those things in an experiment that are purposefully not changed and remain the same throughout the experiment.
Quantitative Data
Quantitative data are data that can be counted or measured and the results can be recorded using numbers.
Qualitative Data
Qualitative data are data that deals with descriptions and data that can be observed.
Celsius Thermometer
A Celsius thermometer is used to measure temperature in degrees Celsius.