The famous scientist Albert Einstein sometimes used “thought experiments” such as imagining himself chasing a beam of light or riding in an elevator in free-fall. These thought experiments, which would not be possible to conduct physically, helped him challenge current scientific thinking and develop his theories of gravity and of special relativity. Write the words or phrases from the box on the lines to complete the paragraph.

avoid sizeselect equipmentstatistical analysis

In actual physical experiments, scientists must carefully and in data collection and analysis. There is variation in nature, so the larger the , the more accurately researchers can determine dissimilarities within each group, and analyze variances between experimental groups and controls. When interpreting data, researchers use to decide if an experimental treatment is significantly different from the control group. When drawing conclusions, the being tested may either be supported, or refuted and to be tested again.