Science Fair Hypothesis Development

This article outlines some ideas, techniques, formatting, and processes involved in designing, developing, and completing an elementary school science fair project.  The following is intended for use by parents and teachers of elementary school children. During this guided experience, children will learn various science-thinking skills, including how to develop a testable hypothesis and how to discern patterns, while also giving examples of interesting science fair projects.  Educational prompts and questions encourage the learner and the teacher to apply the knowledge and skills learned to future occasions.

“Guess Carefully” ~ Developing a Hypothesis:

Once a child/student has chosen a topic for his/her science fair project and developed a good question, he/she needs to develop an educated “guess” as to what the answer to the question will be.  A hypothesis is a proposed explanation made on the basis of limited evidence as a starting point for further investigation.  Guessing carefully, involves researching the topic, so he/she has a basis for his/her answer. Have your child or students practice developing a hypothesis from the questions listed below.  (Since the child (in this instance) is unable to do research before creating a hypothesis in these cases, it does not matter if the hypothesis is based in research. The purpose of this exercise is to practice considering, then framing an effective “guess” as to the outcome of the proposed science fair question.)

  • Question: “Will frozen seeds sprout?”      [As an example, the hypothesis might be: Bean seeds that have been frozen for one month will sprout once planted.
  • Question:  “Do all people have the same body temperature?”      Hypothesis:
  • Question:  “Who has the faster heart rate: children or adults?”      Hypothesis:
  • Question:  “Which brand of paper towel absorbs the most water?”      Hypothesis:

Through research, the proposed “careful guess” becomes more of a prediction.  An accurate prediction can be based on the recognition of a pattern.  

Try it Out: Looking for Patterns

  1. Release a marble from the top of an incline.  Use a piece of masking tape to mark how far the marble rolls, then measure the distance that the marble traveled.  Repeat this activity, but increase the slope (or angle) of the incline. After multiple trials at three ascending inclines, ask your child or students to predict the next approximate distance that the marble will roll from an even greater incline than previously tried.  Have your child or students describe the pattern he/she/they noticed as to the distance that the marble rolled from the ramp compared to the incline of the ramp. Ask: What does this conclusion make you want to try next?
  1. Use a measuring cup to fill six identical drinking glasses with different amounts of colored water (2 ounces, 4 ounces, 6 ounces, 8 ounces, 10 ounces, 12 ounces).  Using a metal spoon, carefully strike the first four glasses in ascending order and listen to the difference in sound. Ask your child or students to predict what the sounds caused by striking the next two glasses will be: higher pitch or lower pitch than the previous sounds?  Have your child or student describe the pattern he/she/they noticed. Ask: What does this conclusion make you want to try next?

Take it Further:

If your child or students is/are interested in the above ideas or related activities, challenge him/her/them to develop one of the ideas into a science fair project.  Use the following format and procedures:

  1. Choose a topic.
  2. Develop an effective associated question.
  3. Propose a hypothesis.
  4. Then test the hypothesis by designing and conducting a supporting experiment.
  5. Perform multiple trials of the experiment.  
  6. Collect and organize the data from the experiment.
  7. Then come to a conclusion to determine whether the outcome supports the original hypothesis.  

Whether the outcome supports the original hypothesis is not the objective of the science fair project.  The purposes of conducting a science project is (a) to learn the processes of and procedures associated with science, (b) to strengthen one’s science-thinking skills, and (3) to develop an understanding of why and how things work the way that they do.

In addition, participating in science fairs give children the opportunity (a) to use science-based tools, (b) to increase one’s mental skills (such as observing, examining, analyzing, comparing, contrasting, classifying, grouping, and sorting), and (c) to communicate their investigations and explanations to others (verbally, or in written, pictorial and/or graphic form).

If you are a teacher, use the following lesson plan based on rolling objects down ramps, to introduce your students to the format of creating a science fair project or to teach about some of the elementary science associated with rolling objects, including Newton’s Laws of Motion.

Elementary Science Fair Project ~ Rolling Objects down Ramps

  • Introduce the Questions.  Have the students keep in mind which of these questions they would like to develop into a science fair project.
  1. How does the weight (mass) of an object affect how far that object rolls?
  2. How does the slope/incline of a ramp affect how far a marble rolls?
  3. How does the surface across which an object rolls affect the distance that it rolls?
  • Do Background Research.  The following activities and discussion will result in different forms of research of the subject matter, science concepts, and physical objects to be used for the science fair projects.  

Show the students two marbles, one made of glass and one made of steel.  Ask them which marble has more mass. Mass is the amount of matter that makes up an object.  Mass, in general, is the weight of an object and can be associated with the size of the object.  For example, if two marbles were the same size as each other, a marble made of steel would have a greater mass than a marble made of glass.  

Ask: If you held two marbles, one in each hand, and dropped them from the same height at the same time, which marble would hit the ground first?  Then try this activity. Both marbles regardless of their mass, should hit the ground at the same time. Explain: Both marbles fell because of gravity.  Gravity is a pulling force that exists between two objects (such as the Earth and the marbles). Gravity pulls at all objects at the same rate.

Newton’s First Law of Motion states that an object at rest will stay at rest until a force (such as a push or pull) acts upon it.  Set a marble on a table or on the floor and ask the students what different forces could move the marble. (Possible answers: someone could pick it up or kick it; the wind could blow it; someone could move the table; etc.). Gravity is holding the marble in place, since gravity is pulling the marble toward the Earth.

Newton’s First Law of Motion also states that an object in motion will stay in motion, traveling in a straight line, until a force (such as a push or pull) acts upon it.  Roll the marble across a table or on the floor and ask the students what different forces could slow the marble, stop the marble, or cause it to change direction so it is not traveling in a straight line. (Possible answers: someone could push it to have it change directions; it could fall off of the table; bumping into a wall could stop it; etc.).

Friction could also slow the rolling marble.  Friction is the resistance that one surface or object meets when moving across or rubbing against another.  For example, a person wearing tennis shoes while walking on asphalt has a high amount of friction between their shoes and the asphalt, which allows controlled movement of the person walking.  Whereas, a person wearing tennis shoes while walking on ice has very little friction between their shoes and the ice, which can cause the person to slip.  Take a short walk around the school while looking at a variety of surfaces across which a marble could roll. Have a discussion about which surface the students think would impose a greater amount of friction on the marble: a plastic tabletop, a wooden tabletop, a cement sidewalk, an asphalt playground, a rug, a linoleum floor, etc.

Newton’s Second Law of Motion states that the force of an object depends upon its mass (how much the object weighs in relation to how big it is) and acceleration (how quickly its speed changes).   In other words, the heavier the object is, the more force is required to move it. Also, the more force given to an object, the faster it will go. And everything else being equal, the faster an object is moving, the longer it takes to slow it down.  Therefore, if you roll a steel marble and a glass marble each down an identical ramp, the heavier marble may take more time to start moving, but given enough travel distance, will accelerate faster. The faster moving object will take longer to slow down. [This is an example of one of the experiments/science fair projects that can be performed.]

  • Construct a Hypothesis.  Based on the above discussion and research, have the students select their science fair “question” (problem statement), such as “How does the weight (mass) of an object affect how far that object rolls?”  Then have them propose a testable, measurable hypothesis (or answer to this question), such as “Traveling at the same speed, a steel marble will travel a further distance from the end of the ramp than a glass marble will.”

Other problem statements and hypotheses can be used and tested, but remember that there should only be one variable, such as different types of marbles, or different ramp slopes, or different surfaces, etc.  Remind the students that the purpose of the experiment/science fair project they will perform is not to be correct, but to learn information by working like a scientist.

  • Test Your Hypothesis by Doing an Experiment
  • Design, then Follow Your Procedure
  • Gather Your Materials

Depending on the experiment, the students may need (a) glass and/or steel marbles, tubes, such as cardboard tubes from wrapping paper or 3-foot long wooden boards, for ramps, (b) yardsticks or measuring tapes to perform measurements of the distance traveled, (c) different surfaces, such as a rug and a linoleum floor, (d) tape, (e) paper, and (f) pencils.

Guidelines to setting up the ramps:

  1. Have the students use the ruler to mark their papers showing one inch increments that they can tape to the wall.  In this way, students can set the top of their ramp at a 2-inch height, a 4-inch height, a 6-inch height, an 8-inch height, and a 10-inch height (as an example).
  2. Depending on their experiment, the students can predict if the marble(s) will roll farther and farther with each increase in height of the ramp.  If they are performing an experiment on increasing ramp heights (increasing slopes), they should only use one type of marble at a time, as the variable in this experiment would be the slope of the ramp. Capture all data to organize on a chart.
  3. Following an experiment using a series of trials with a glass marble rolling down increasing heights of slopes, they can perform the same experiment with the steel marble to see if they get similar results.
  4. Another series of experiments could be keeping the ramp at the optimal height (this can be discovered in the above mentioned experiment) and test out the difference between the glass and the steel marble ….. or using only one type of marble and work across different floor surfaces, etc.
  5. Remind the students to collect and organize their measurements that they gather so they will be able to analyze the information once the experiment is completed.  
  • Analyze Your Data and Draw a Conclusion.  After the activity, discuss the results with the students.  For example, they should discover that with increasing ramp slopes, there is a point at which the marbles travel less far.  This is due to the increased amount of bounce ….bounce causes the marble to lose energy, therefore it cannot travel as far.
  • Communicate Your Results.  After discussing the results, have the students record their results in a project report similar to the chart below.  You can also collect the data from other test groups in other classrooms to increase the size of your trials/sample size.
Analyze Results

Before you go, check out this article that discusses science fair project judging.

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