1. Inferences & Observations “Do you see what I see?”

2. Inferences • ... Are reasonable conclusions derived from observations. • Inferences are based on your prior knowledge and past experiences. • Scientists make inferences all the time, which may prove a certain link or connection, but don’t prove cause. • Inferences can lead to hypotheses. • Inferences can change.

3. Observations • “You can observe a lot just by watching” • An observation is the gathering of information by using our five senses • Sight • Smell • Hearing • Taste • Touch

4. Qualitative Observations • Qualitative observations describe what we observe. • “Qualitative” = quality (descriptive) • These observations use adjectives to describe something. • Example: The flower has white petals

5. Quantitative Observations • Quantitative observations measure what we observe. • Quantitative = quantity (numerical) • These observations use numbers to describe something. • Example: The flower has seven petals

6. Which is better? • Both types of observations are valuable in science, although quantitative observations allow for precise and objective comparisons.

7. Putting it all together • Quantitative observation: The grass is wet. • Possible inferences: • It recently rained • A dog peed on the grass • A sprinkler was turned on • There is dew from the morning

8. Variables & Controls In experiments...

9. Independent Variable • The independent variable is the one thing that is changed by the scientist. • This is the factor manipulated by the researcher, and it produces one or more results. • To insure a fair test, a good experiment has only one independent variable.

10. Dependent Variable • The dependent variable is what you measure in the experiment and what is affected during the experiment. • The dependent variable responds to the independent variable. • It is called dependent because it "depends" on the independent variable.

11. Control Variable • A control variable remains unchanged or held constant in an experiment. • A Controlled Variable is anything else that could influence the dependent variables. Therefore, controlled variables must be carefully monitored and kept equal in your experiments otherwise they could mess up your experiment.

12. TRY THESE EXAMPLES • http://sciencespot.net/Media/scimethodconvar.pdf