Science: The Scientific Method
Observations, hypotheses, variables, and conclusions
Science: The Scientific Method
Observations, hypotheses, variables, and conclusions
Science - Grade 6-8
- 1
List the scientific method steps in a reasonable order from beginning to end.
Start with noticing something and end with explaining what the results mean.
A reasonable order is to make an observation, ask a question, form a hypothesis, plan and carry out an experiment, collect and analyze data, and draw a conclusion. Scientists may repeat steps as they learn more. - 2
A student notices that a plant near a window grows taller than a plant on a shelf. Write a scientific question the student could investigate.
A good scientific question is: How does the amount of sunlight affect the growth of a plant? This question can be tested with an experiment. - 3
Write a hypothesis for this question: Does the amount of water affect how fast bean seeds sprout?
Use an if-then statement.
A valid hypothesis is: If bean seeds receive a moderate amount of water each day, then they will sprout faster than seeds that receive too little water. This prediction connects the variable to the expected result. - 4
In an experiment, a student changes only the amount of light each plant receives. What is the independent variable?
The independent variable is the amount of light each plant receives. It is the factor the student changes on purpose. - 5
In the same plant experiment, the student measures how many centimeters each plant grows in two weeks. What is the dependent variable?
This is the variable that is measured.
The dependent variable is the plant growth measured in centimeters. It is the result that changes in response to the amount of light. - 6
A student tests paper towel brands to see which absorbs the most water. Name two variables that should be kept constant for a fair test.
Two constants could be the size of each paper towel sheet and the amount of water used in each trial. Keeping these factors the same makes the test fair. - 7
A class wants to test whether music affects quiz scores. Why is it important to have a control group in this experiment?
Think about what students need to compare the test group to.
A control group is important because it provides a comparison. For example, one group could take the quiz without music so the class can tell whether music changed the scores. - 8
A student says, "My experiment proved my hypothesis was correct." Rewrite this statement so it is more scientifically accurate.
A more accurate statement is: My results supported my hypothesis. In science, evidence can support or not support a hypothesis, but one experiment does not prove it with absolute certainty. - 9
Look at this result: Plants given 6 hours of light grew 9 cm, plants given 8 hours grew 12 cm, and plants given 10 hours grew 11 cm. Which light amount produced the greatest growth?
Compare the growth numbers, not the light numbers.
The plants given 8 hours of light produced the greatest growth. They grew 12 centimeters, which is more than 9 centimeters and 11 centimeters. - 10
If a scientist repeats an experiment three times and gets similar results each time, why does that make the conclusion stronger?
Repeated trials make the conclusion stronger because they show the results are consistent and less likely to be caused by chance or a mistake. Repetition improves reliability. - 11
A student observes that ice melts faster on metal than on plastic. Identify one observation and one inference in this situation.
An observation is noticed directly, while an inference is an explanation.
One observation is that the ice melts faster on the metal surface than on the plastic surface. One inference is that metal transfers heat more effectively than plastic. - 12
After completing an experiment, what information should be included in a good conclusion?
A good conclusion should describe the results, explain whether the data supported the hypothesis, and mention evidence from the experiment. It can also include possible errors or ideas for future investigation.