Helpful Hints for Science Experiment Success
Most children love the hands-on aspect of planning a science experiment.¬† In order to create a successful science experiment that produces valid results, it is important to follow a process known as the scientific method.
Step 1:¬† Identify a problem or question
To determine a focus for an experiment, identify a problem that must be solved or a question that needs to be answered through experimentation.¬† This is how scientists work to solve problems we face in everyday life.¬† Encourage your child to explore his environment to locate a problem that needs solving.¬† For a child, the question can be informal and might be something as basic as trying to determine why a houseplant is not thriving.
Question:¬† Why is our philodendron plant not growing?
Step 2:¬† Form a hypothesis
In order to decide how to proceed with the experiment and solve the problem, have your child determine a hypothesis.¬† A hypothesis is an educated guess about how things happen or work.¬† In the hypothesis, a formal prediction is made as a possible answer to the problem or question.¬† Most of the time, the hypothesis is written as an ‚ÄúIf _____, then______.‚ÄĚ statement.¬† The hypothesis should be testable, explaining what to do as part of the experiment to investigate the problem and stating what will happen as a result of the experiment.
For example, if your child observed that the plant‚Äôs leaves are yellow instead of green, it doesn‚Äôt seem to be showing any new growth, and the soil in which it is potted seems to be quite soggy, she may determine that the plant is getting too much water.¬† The hypothesis might be written as follows.
Hypothesis:¬† If a philodendron is watered only once per week, then plant growth will increase.
Step 3:¬† Develop an experiment
To test if the hypothesis is correct, develop an experiment.¬† Every experiment has variables, or elements, that are controlled and uncontrolled.¬† When working with children to explore the scientific method, it is best to limit the number of controlled variables.¬† A controlled variable is simply a part of an experiment that can be controlled.¬† An uncontrolled variable is the part of the experiment that your child is trying to measure.
In testing the hypothesis, guide your child to set up the experiment in the following manner: Plant three philodendrons in the exact same type of container with the exact same type and amount of soil.¬† Group the plants together to guarantee that each receives the same amount of oxygen and sunlight.¬† The only variation in care is the frequency with which each plant receives water.¬† One plant is watered once a day, another is watered every other day, and the third is watered once per week.¬† This variation is the frequency of watering and is the manipulated variable in the experiment.¬† With each watering, the plants receive the exact same amount of water.¬† In this way the controlled variables include the type of plant, the environment in which the plants live, and the way in which the plants are watered.¬† The uncontrolled variable, sometimes known as the responding variable, will be how much each philodendron will grow.
A mistake many families make when developing a science experiment is to include too many variables.¬† Limiting the variables will result in a more reliable experiment in which the results can be replicated.¬† For this experiment, for example, the results would be muddled if multiple types of soil were introduced into the experiment, the amount of water received varied at each watering, or the amount of sunlight was limited for some of the plants.¬† Each of these variables could affect the outcome of the experiment and it would not be possible to prove the hypothesis.¬† It would not be possible to determine if watering the philodendron once per week resulted in increased growth, or if that growth was the result of one of the other variables introduced into the experiment.
If this experiment is designed for entry in a science fair, it is during this step in the scientific process that your child should take specific notes detailing all of the materials used as part of the experiment and the steps taken in setting up and running the experiment.¬† This information is critical to enable someone else to replicate the experiment.
Step 4:¬† Collect and analyze results
During the course of the experiment, it is important to collect data that tracks the progress of the experiment.¬† For this sample experiment, data that would be tracked would include the dates and amount of water given to each plant.¬† It would be important to measure the plants at regular intervals and document any growth, being sure to measure each plant on the same day at the same time.¬† Notes should be taken regarding the general health of the plant, such as the color of the leaves, quantity of leaves, etc.
The notes and observations taken during the experiment should be organized in a way that makes the information easy for another person to understand and interpret.¬† Ideally, data should be recorded in charts and graphs.¬† It may be helpful to document the progress of the experiment with photographs as well.
Once the experiment has concluded and the data organized, it is time to evaluate the results.¬† Think about the hypothesis that was formulated in relation to the data.¬† If the experiment was run properly, it should be possible to confirm or disprove the hypothesis.
Step 5:¬† Conclusion
In working through the scientific method, once the experiment is complete and the data analyzed, your child should develop a statement called a conclusion, which is one that accepts or rejects the hypothesis.¬† A scientist might run an experiment many times before determining a conclusion.¬† A student may not have the opportunity to do so.¬† The conclusion will be based upon the results of the experiment.¬† In the conclusion, it is necessary to state whether or not the hypothesis was correct based upon the data collected during the experiment.¬† Your child may also choose to include recommendations for further study and ways to improve the experiment in the future.
For the sample experiment, examining the growth made by each philodendron over time would determine if watering this type of plant once per week increases growth.¬† If so, your child has successfully proven the hypothesis.¬† If not, that fact must be stated along with suggestions for how this question of increasing growth in philodendrons may be explored in the future.
Step 6:¬† Communicate the results
For students preparing an experiment for a science fair, fair organizers will put together guidelines for presentations and displays.¬† Children working at home will enjoy the opportunity to present their findings to family and friends as a culminating activity.