Science Fair - Selecting and Defining the Topic

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SWBAT develop an overview of their planned science fair experiment.

Big Idea

What am I going to do for science fair?

The Need for the Lesson

Selecting a topic for science fair is no small task. Students need an opportunity to think through the processes involved in their initial idea. Sometimes the project will involve the whole family and items to be purchased.

In this lesson students write an overview of their science experiment so that it is clear what needs to be done and they can work with their families to begin the experimental process.

We will work on elements of the science fair project at school. The expectation is that the experiment itself will be done at home.

Investigation Preparation & Summary

5 minutes

In this lesson, students will ask a question or state a problem that can be answered through experimentation or design as their science fair project (SP1 - Asking questions and defining problems). By writing our an overview of their science experiment, students will begin the initial planning of their experiment or design (SP3 - Planning and carrying out investigations).

Students in Action

45 minutes


One of the first things we do to prepare for science fair is to create a timeline for all involved. This gives students, parents, teachers and anyone else interested a guide for completing science fair milestones.


We ask out students to submit a science fair topic for approval by their family and teachers. This is to make sure the family knows the topic and agrees to support the student with supplies and space needed to complete the topic. The teacher approval is to be sure the topic is not too difficult but also is stretch for new learning for the student.


Out students and families routinely use this link at Science Buddies to help them select a topic. This is also where I offer support for students by reviewing their interests using the Mission Patches created in a previous lesson as a guide.


Next I review the Writing an Overview of Your Experiment document with students.

What is your question? At the end of your science fair project, what question will you be able to answer?

What are your experimental controls?

In a pure science experiment this would be the control against which you will compare results. For instance, if I wanted to test the drop time of parachutes, I would drop my "passenger" without a parachute to show whether or not the parachute made a difference. For many of my students it is a challenge to set an experimental control. If they are testing different types of baseball bats, they may only have wooden and aluminum bats to compare - so what would be their experimental control? I modify this for students when we are filling out this paper as a class. I tell students I will conference with them individually. For now we list the control variables or what it is we plan to keep the same throughout the experiment. In the parachute example, this would be the same drop height, same "passenger", same timer and so on.

What is your independent variable? What is the one thing you will change in your experimental trials? This is also a hard question for students. They often want to change several things. We discuss the parachute example again. The only thing I would change would be the parachute.

What is your dependent variable? What will you measure? Students should include units in this answer. We will measure the drop time of the parachute in seconds.


Before we fill out the bottom half of the paper. We quickly go around the room and each student shares what they have written. This helps students who had trouble thinking of answers by soliciting help from the class. They simply say I am not sure what I should be measuring for my dependent variable. I ask their classmates to help make suggestions. This strategy gives all students practice and review of the key elements of the experiment.

Also, as students are sharing, I ask other students if they have any questions about the experiment. Students are encouraged to take notes in their science journal. These questions can be used latter to help drive the research portion of the science fair project.

Next students complete the bottom half of the paper. These should be complete sentences. When they are finished they have a well formatted paragraph that gives an overview of their experiment.


Students may not be able to complete the hypothesis at this time. Students tell me that the hypothesis is an educated guess. If that is true then upon what education is your guess based upon? At this point, most students have not yet begun their research so they are not sure what they expect their experimental results to show.

We encourage students to write their hypothesis in an If... then... because... statement format. The because reminds students to base their conjecture on research.

In this short video, I take a closer look at a student sample.