Scientific Investigations

Science The nature of the world is understandable. Science is based on evidence. Science is a blend of knowledge and inovation. Science ideas are durable, yet maybe changed as new information is presented. Science is complex. Scientists try to remain objective.

Scientific Experiment The heart of an experiment is ASKING a QUESTION and SEARCHING for an ANSWER. To begin an experiment, first brainstorm and decide a topic. Next, research the topic to determine a TESTABLE question. Then, begin the experiment.

Parts of a Scientific Experiment Title Hypothesis Materials Procedure Data / Observations Results Conclusion

Title Pertains or relates to the experiment. Is short Is designed to catch the attention of others May be completed after the actual experiment

Hypothesis Is an educated guess about what you think will happen in the experiment. Answers the question or purpose of the experiment. Is based on research. Is written in a complete sentence. (Omit ‘I think’ or ‘I believe’) Contains independent and dependent variables.

Variables Independent variable (manipulated)- what is being tested or is deliberately adjusted. There can be only ONE independent variable. Dependent variable (responding)- what is measured or observed as a result of adjusting the independent variable Constant- what remains the same in each experimental trial so any changes are the result of the independent variable

Let’s Look at an Example Question- Will adding fertilizer produce more tomatoes? Hypothesis- IF you use fertilizer, THEN you will have more tomatoes. Variables- Independent (fertilizer) Dependent (the number of tomatoes) Constants- same kind of plants, same pot, same temperature, same amount of water

You try- Question- Which type of sugar, brown or white, will attract more ants? Hypothesis- If you use brown sugar, then you will attract more ants. Variables- Independent- brown sugar Dependent- number of ants Constants- Same location, same amount of sugar, same amount of time

Materials All items used to complete the experiment, except pencil and paper to log the results Procedure Step by step account of how experiment was performed. (Numbering 1, 2, 3, etc. is easiest) Be specific- it must be detailed enough for anyone to follow the steps and get the same results.

Results / Data Any changes in the dependent variable Observations made during the experiment Must be precise May be displayed in charts, graphs, pictures, or other ways

Conclusion Correct answer to the question Must be in sentence form Restates the hypothesis

A good experiment will have controls or a control group when necessary. A control is a standard of comparison for checking or verifying results of an experiment. It assures that the changes in the dependent variable are the result of the independent variable. Experimental Controls

Controlled Practice- OOPS! Practice Controls If testing to see if fertilizer makes more tomatoes grow, one plant would have NO fertilizer. If testing to see what color light makes plants grow taller, the control group would be- A plant in plain light If testing to see if adding salt to water will make an egg float better, the control would be- An egg placed in pure water