The scientific method is a process that investigates a problem. It is made up of four components: hypothesis, experiment, observation and conclusion. The hypothesis is the explanation of the problem and is a proposal to be tested; the experiment is the procedure used to test the hypothesis; the observation is the data gathered during the experiment; and the conclusion is whether the hypothesis is valid based on what was observed. These scientific method steps represent a powerful tool to determine whether an assumption is correct or not. The following scientific method experiment ideas demonstrate how the scientific method can be used.
Oil Spill Effects on Aquatic Plants
A possible hypothesis regarding the problems with oil spills is, "Oil has a negative effect on aquatic plants." To test the hypothesis using scientific method steps, aquatic plants have to be exposed to oil and the results observed. Fill two test tubes and two beakers with water. Place two hydrilla plants into the two beakers, one in each. Then invert the test tubes, covering the ends with your thumb so they don't spill, and place one into each beaker, removing your thumb as the mouth of the test tube meets the surface of the water. Insert the tops of the plants into the test tubes, without letting the water out, and lean the tubes against the edges of the beakers. Place the beakers side by side on a window sill.
Pour an ounce of motor oil into one of the beakers and note the effect on the appearance of the plants and on the amount of oxygen that collects in the test tubes. Based on these observations, conclude that the oil has a negative effect on the plants or not. Try the same experiment with different amounts of oil to find out how much oil is needed to have an effect on the plants.
Plant Growth and Fertilizers
A hypothesis investigating farming practices could be, "Fertilizers make plants grow more quickly." To test this hypothesis plant two mung beans in two pots and place side by side on a window sill. Add fertilizer to one pot and then equally water the two pots on a regular basis.
After the beans form leaves and start growing, measure and record the height of each plant daily for at least a week. Based on whether the fertilized plant is bigger than the non-fertilized plant, conclude that fertilizers make plants grow more quickly or not. Repeat the experiment with different amounts of fertilizer to find out whether too little or too much fertilizer has an effect.
Water Displacement and Flotation
A hypothesis looking at why some objects float and others don't could be, "Whether objects of the same weight float depends on their volume." To test the hypothesis cut five equal squares of aluminum foil about five by five inches each. These squares weigh the same. Roll each square into a ball, the smallest as tight as you can and the largest quite loose with the others in between. The tight ball has the lowest volume while the loose ball has the largest.
Place each ball in a container of water and record whether it floats. Based on your results, conclude whether the volume affects flotation. Collect other objects that weight the same but have different volumes and observe which ones float if your original experiment is inconclusive.
The Effect on Taste of Sugar Substitutes
A hypothesis on the effectiveness of sugar substitutes could be, "Sugar substitutes taste as good sugar." To see if the hypothesis is true, prepare a batch of lemonade and place sugar in one sample while sweetening the other with a sugar substitute. Get at least ten people to try both and record which they say tastes better.
Based on whether your taste testers say the lemonade with a sugar substitute tastes as good or better than the sugared drink, the hypothesis is true or false. Try the taste test with other foods such as cookies, cakes or ice cream to get a more complete picture. The test results will show whether a sugar substitute is as good as sugar in all cases, in none of the cases or sometimes.
Conclusion: The Scientific Method for Kids
These simple scientific method experiments show how the scientific method is designed to validate any ideas that relate to processes that can be tested. Scientists try to develop a hypothesis to explain something and then test it using the scientific method. All of science is based on hypotheses that have been tested and found to be correct while other views have proved to be wrong the same way.
About the Author
Bert Markgraf is a freelance writer with a strong science and engineering background. He has written for scientific publications such as the HVDC Newsletter and the Energy and Automation Journal. Online he has written extensively on science-related topics in math, physics, chemistry and biology and has been published on sites such as Digital Landing and Reference.com He holds a Bachelor of Science degree from McGill University.