Brain Teasers… 1. Which soldier is the largest? A B C 2. How many legs does this elephant have?

INVESTIGATION AND EXPERIMENTATION (I & e) : What is “Science”? Observations, Inferences, and Controlled Experiments

1. Science is an attempt to explain natural phenomenon. 2. All scientific knowledge is based on accurate observations of the natural world.

3.-An Observation an act of carefully watching something and collecting facts. -Observations are: Gathered by using our senses (qualitative) Gathered by using our senses (qualitative) Can also be gathered by taking measurements (quantitative) Can also be gathered by taking measurements (quantitative) -Characteristics of good Scientific Observations: Accurate – Quantify or measure whenever possible Accurate – Quantify or measure whenever possible Detailed and Complete – Consider all parts of the observation Detailed and Complete – Consider all parts of the observation Repeatable – All observers see the same thing or each time the event is observed the description is the same Repeatable – All observers see the same thing or each time the event is observed the description is the same

4. There are two types of observations: a) Qualitative Observations—An observation that describes the physical characteristics or qualities of something. a) Qualitative Observations—An observation that describes the physical characteristics or qualities of something. (Ex. The water is hot; The M&M is small; The egg smells bad; The leaf is orange, etc) b) Quantitative Observations—An observation that is based upon numerical information or a measurement of some type. b) Quantitative Observations—An observation that is based upon numerical information or a measurement of some type. (Ex. The water is 45ºC; The M&M is 1.7 cm in length; The car is traveling at 65 Km/hr)

5. Good scientific observations are used in order to make predictions, or inferences, about the natural world.

6. To infer means… to make a prediction based on observation. 7. An inference is a conclusion that is formed by using logic and what is previously understood about the natural world. Ex Which statement is an inference? a. It has 3 candles. b. It is a cake for some one turning 3 years old. c. It is a round cake with squiggly black lines.

8. Good scientific inferences: a) Consider all available observations. b) Fits the understanding of the natural world c) are the most logical and rational conclusion.

9. All inferences must be based on previous observations of the natural world. 10. Inferences are the basis for all Scientific Theories and Hypotheses.

11. What’s the difference? Theory v. Law v. Hypothesis **A scientific theory is a well-tested explanation that unifies a broad range of observations. (Ex: Theory of Plate Tectonics, Evolution, Cell Theory, Germ Theory, etc.) - A scientific theory may be revised as new evidence is presented. -A theory is like the automobile. -WHY?? Components of it can be changed or improved upon, without changing the overall truth of the theory as a whole.

**A scientific law is a consistent principle that is repeatedly observed in nature and is usually mathematical. -It is always true. (Ex: Gravity, Speed of light, Newton's laws of motion, the laws of thermodynamics, Boyle's law of gases, the law of conservation of mass and energy, and Hook’s law of elasticity. ) (Ex: Gravity, Speed of light, Newton's laws of motion, the laws of thermodynamics, Boyle's law of gases, the law of conservation of mass and energy, and Hook’s law of elasticity. ) A scientific law is like a slingshot. WHY?? A slingshot has but one moving part--the rubber band. If you put a rock in it and draw it back, the rock will fly out at a predictable speed, depending upon the distance the band is drawn back.

12. Scientific Method and Controlled Experiments **A hypothesis is a testable possible explanation of an observation. -In science, a hypothesis is useful only if it can be tested. -Scientific hypotheses are most often tested by the process of experimenting. An attempted explanation needs to be tested to be accepted.

Scientific Method I. State the Problem II. Form a Hypothesis III. Set up a Controlled Experiment IV. Record and Organize Data V Formulate a Conclusion

Scientific Method I. State the Problem— Form of a question that indicates the purpose of the investigation. II. Form a Hypothesis— This is a possible explanation or answer to the problem/question presented. (Hypotheses are not proven but supported by evidence)

*III. Set up a Controlled Experiment— An experiment is basically a comparison of two situations. An experiment is basically a comparison of two situations. One of the situations is left constant, while one factor of the other situation is changed in order to test the affect of that specific change. Control – a set of conditions used for comparison purposes; can either be original conditions, real-life conditions, or specific conditions set by the experimenter

There are three types of factors that may affect an experiment. These factors are called variables. 1. The factor that is purposely changed by the experimenter is called the independent variable (also called the manipulated variable). (also called the manipulated variable). 2. The factor that changes in response to the independent variable is called the dependent variable (or the responding variable). (or the responding variable). 3. The rest of the factors that the scientists keep the same in the experiment are called the controlled variables. variables.

It is important to test the affect of changing only one variable in order to get accurate results. **If only one variable is changed and all the other factors are kept the same then we say that it is a controlled experiment. ***Uncontrolled conditions can lead to inaccurate results.

IV. Record and Organize Data— - Data tables, graphs, charts, observations, etc. - Data tables, graphs, charts, observations, etc. V. Conclusion— - Indicate whether or not your hypothesis was correct - Describe how the data provides evidence for your conclusion - Identify possible sources of error in your experiment - Identify possible sources of error in your experiment

Practice Problem : Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product he buys the itching powder and compares it t his usual product. One test subject is sprinkled with the original itching powder, and another test subject was sprinkled with the experimental powder. Subject A = 30 min itches Subject B = 45 min itches

Identify the: 35. Control group - why? 36. Independent variable - why? 37. Dependent variable - why?

Two Students were testing the amount of fertilizer that would best promote the growth of strawberries in a garden. Which could be unavoidable sources of error? A.Length of study B.Variation in the strawberry plants C.The cost of watering the plants D.Fertilization during the study

In most stable freshwater environments, populations of Daphnia are almost entirely female and reproduce asexually. However, males are observed in low oxygen environments or when food is scarce. Based on these observations, a researcher suggests that male Daphnia develop in response to unfavorable environmental conditions. This is an example of a A.Result B.Theory C.Procedure D.hypothesis