Warm Up 8-14 1. If you are directed to mix an acid and water, which should you add to which? 2. What does a carcinogen do? 3. What is the purpose of an SDS? 4. What section of an SDS should you look at to find first aid procedures? Safety Quiz Tomorrow! Hooray!! What is Science? Science is the use of evidence to construct testable explanations and predictions of natural phenomena as well as the knowledge generated through this process. We use the Scientific Method in order to achieve this. The Scientific Method The Scientific Method is a 6 step process that is used to address ANY scientific question. Step 1: Purpose: Ask a Question Example: Would eating carrots every day help improve eyesight? The Scientific Method Step 2: Do Background Research Example: Has anyone asked this before? What other research has been done on this subject? The Scientific Method Step 3: Construct a hypothesis Remember that hypotheses are tentative (not certain) and testable; they must be supported by observational evidence; and tested over a variety of conditions which can turn them into theories. Example: If I eat 6 carrots a day for 1 year, then my vision will improve. The Scientific Method Step 4: Test your hypothesis with an experiment Example: -Gather 3 groups of randomly chosen people with similar eye health -Have all subjects undergo a vision test at the start of the experiment -Have Group 1 eat NO carrots a day for 1 year -Have Group 2 eat 3 carrots a day for 1 year -Have Group 3 eat 6 carrots a day for 1 year -Get all subjects a vision test at regular intervals throughout the experiment The Scientific Method Step 5: Analyze data and draw conclusions Example: -Group 1 showed a -2% improvement in vision -Group 2 showed a 1% improvement in vision -Group 3 showed a 3% improvement in vision Conclusion: Eating carrots every day have a positive effect on vision in humans The Scientific Method Step 6: Report your results and conclusion. Was your hypothesis correct? It is important to share your experiment to better science as a whole. Now, if anyone ever has the same question, they can do research and find your results! The Scientific Method Step 7: Revise based on your data/conclus ions, and make a new hypothesis! Take 2 Take 2 minutes to: • Come up with a question that you would like to test with an experiment. • Form a hypothesis for this experiment (an easy format is an “If ____, then____) 0 Timer 2 Imagine that money, resources, and test subjects are not an issue! Important Factors in an Experiment • Independent Variable: The part that you CONTROL in the experiment. You only want 1 independent variable!! • Dependent Variable: The part that you are measuring. It changes (or doesn’t change) based on your independent variable. • Constant: The things that are always kept the same. Independent vs. Dependent If I poke a chicken in the head multiple times, then it will become angry. Independent vs. Dependent Independent Variable: Poking in the head Dependent Variable: Chicken Becoming Angry Important Factors in an Experiment • Control Group: A control group is a group of subjects that you do not change at all. This is so you have something to compare your experimental group to. (There is not always a control group) • Sample Size: Your sample size is the number of subjects you test your hypothesis on. The bigger the sample size, the more accurate your data is. Important Factors in an Experiment • Repeatable: All experiments should be repeatable. • This means that if someone else ever wanted to do your exact same experiment, they should get the same results. Theory vs. Law A scientific theory is based on natural and physical phenomena and is capable of being tested by multiple independent researchers. Theories are well-established and highly- reliable explanations, but can change due to new areas of science and new technologies being developed. Theory vs. Law A scientific law is a statement based on repeated experimental observations but will always apply under the same conditions. (Ex: Newton’s Laws of Motion, Universal Law of Gravitation, Coulomb’s Law) .