Observation versus Inference
In order for there to be a need for an experiment, scientists first make observations. Observations are when we use our five senses (seeing, hearing, touching, tasting, and smelling) to collect information. Often times, scientists are able to make an inference, or come up with an explanation, for what they observe. Other times, they develop an experiment to find out more information. In that case, scientists will take an educated guess, or prediction, based on observations called a hypothesis. They will then design a well thought out experiment to test their guess.
Steps to Solving Problems through Experiments
Elements of Good Experimental Design
In order for an experiment to be well thought out, it must include the Elements of Good Experimental Design. The experiment must:
1- Builds on previous research
2- Describe all steps in the procedure clearly and completely
3- Describe all data to be collected
4- Keep all variables, except the ones being tested, the same
5- Include a control (or placebo) for comparison
6- Uses an appropriate group of subjects
7- Include a large sample size (number of people or trials tested)
8- Can be reproduced by other investigators to give similar results.
9- Respect all human and animal subjects
* Elements may vary, depending on the problem being studied*
The activities in the first part of this unit will explore each of these elements with a focus on studying people. For instance to learn about placebos and interpreting data, we will talk in depth about clinical trials.
By the end of Part A, students will need to be able to write a well designed experiment (abiding by the elements), organize and interpret data, and form a well supported conclusion based on the data.
1- Builds on previous research
2- Describe all steps in the procedure clearly and completely
3- Describe all data to be collected
4- Keep all variables, except the ones being tested, the same
5- Include a control (or placebo) for comparison
6- Uses an appropriate group of subjects
7- Include a large sample size (number of people or trials tested)
8- Can be reproduced by other investigators to give similar results.
9- Respect all human and animal subjects
* Elements may vary, depending on the problem being studied*
The activities in the first part of this unit will explore each of these elements with a focus on studying people. For instance to learn about placebos and interpreting data, we will talk in depth about clinical trials.
By the end of Part A, students will need to be able to write a well designed experiment (abiding by the elements), organize and interpret data, and form a well supported conclusion based on the data.
Variables
Manipulated (Independent) Variable- What "I" change, or manipulate;
what is being tested (Input)
Responding (Dependent) Variable- What is being measured;
observe how it "responds" (Output)
Controlled Variable- Any other factors that could effect the results
should be kept the same, or controlled
what is being tested (Input)
Responding (Dependent) Variable- What is being measured;
observe how it "responds" (Output)
Controlled Variable- Any other factors that could effect the results
should be kept the same, or controlled
Spongebob Variables and Controls- Tutorials
Ms. Cuje's Explanation of Clinical Trials:
How to use evidence from a data table to conclude whether a medicine is safe and effective
Using placebo effect as new pain treatment! Watch video below.
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