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Ingredients for a Good Experiment. Controlled experiment- Only change 1 variable at a time. Variable. Factors that can change in an experiment Test only 1 at a time! Independent- the 1 variable that you purposely change to test a hypothesis
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Ingredients for a Good Experiment Controlled experiment- Only change 1 variable at a time
Variable • Factors that can change in an experiment • Test only 1 at a time! • Independent- the 1 variable that you purposely change to test a hypothesis • Dependent- the variable that may change in response to the independent variable • What you are trying to measure
Constant & Control Group Constant Control Group • Characteristics that you keep the same in all trials • “Normal” group • No variables are changed • The results of experiments are compared to this group
Bias • When what a scientist expects to happen affects the results Do not include bias in scientific process
A group of students decided to run an experiment to see if cold water freezes faster than hot water. The students set up three 100 mL beakers: the first had 100 mL of cold water, the second had 100 mL of boiling water, and the third had 100 mL of room temperature water. They placed all three beakers in the same freezer and checked on them every 15 minutes, writing down everything they observed. After making their observations, and running the test 2 more times, to their surprise, the students concluded that hot water freezes faster than cold water.
Temperature Time (it takes water to freeze) • A group of students decided to run an experiment to see if cold water freezes faster than hot water. The students set up three 100 mL beakers: the first had 100 mL of cold water, the second had 100 mL of boiling water, and the third had 100 mL of room temperature water. They placed all three beakers in the same freezer and checked on them every 15 minutes, writing down everything they observed. After making their observations, and running the test 2 more times, to their surprise, the students concluded that hot water freezes faster than cold water. Any other constant not mentioned?
Scientific Theory Scientific Theory Scientific Law • A well-tested explanation for a wide range of observations or experimental results. • Future testing can still prove an accepted theory to be incorrect. • A statement of what scientists expect to happen every single time under certain conditions