THE SCIENTIFIC PROCESS C H A P T E R 3

Transcription

1 THE SCIENTIFIC PROCESS C H A P T E R 3

2 OBJECTIVES You will be able to understand: What does learning by inquiry mean? What qualifies as Scientific Evidence? What is a Scientific Theory? What is a Scientific Hypothesis? Why must a hypothesis be testable?

3 NATURAL LAWS The universe follows a set of rules called Natural Laws. Definition: Rules that describe an action or set of actions in the universe. Everything that happens in the world, obeys the same natural laws

4 PRIMARY GOAL OF SCIENCE To discover what the natural laws are. The most reliable way to discover these natural laws is through? Scientific Inquiry Process of learning that starts by asking questions and proceeds by seeking the answers to the questions.

5 SCIENTIFIC METHOD An organized process of answering scientific questions. It is a systemic and logical way to build on evidence. It is based on understanding of our natural world. What does the natural world consists of?

6 SCIENTIFIC METHOD STEPS State a problem/ Pose a scientific question Observation/Research Formulate a Hypothesis Experiment Collect and Analyze Results Conclusion Communicate results

7 HOW IS SCIENCE LIKE SOLVING A MYSTERY? Inquiry = Crime investigation with a mystery to solve. Accurately describe who did what, when they did it, and how? How would a detective do this? Detective must deduce (figure out) what happened in the using logical thinking and information collected in the? Past, present

8 HOW TO SOLVE THE MYSTERY? What are some steps the detective should take to solve the mystery? Search for evidence and clues to help answer questions. Come up with a theory about what happened. Theory A possible explanation Need evidence to back theory up.

9 STEPS A THEORY MUST PASS TO BE ACCEPTED The theory must be supported by enough real evidence. There cannot be a single piece of evidence that contradict the theory. The theory must be unique. If you have passed all three steps, you have solved your mystery by using the process of inquiry!

10 SCIENTIFIC EVIDENCE What types of evidence qualify as scientific evidence? Do feelings or opinions count? i.e. The potted plant did not grow much because it was an old plant that had been in the pot for many years. Does what other people think qualifies as scientific evidence indeed qualify? No and No. Scientific Evidence may include: Numbers Tables Graphs Words Pictures Sound recordings Other information

11 WHEN IS EVIDENCE CONSIDERED SCIENTIFIC Scientific evidence must be Objective and Repeatable. What does this mean? Objective: Evidence that documents only what actually happened as exactly as possible. Repeatable: Describes evidence that can be seen independently by others if they repeat the same experiment or observation in the same way. Ex. Gallileo s Sketches

12 SCIENTIFIC THEORIES A human attempt to describe a natural law i.e. What makes a hot cup of coffee cool down? Was the Theory of Caloric proved or disproved? A scientific explanation supported by a lot of evidence collected over a long period of time. Charles Darwin s theory of evolution by natural selection is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits.

13 HOW ARE THEORIES TESTED AGAINST EVIDENCE Scientists are always testing theories against new experiments and new evidence. Why? To prove or disprove the theory! One of Two things can happen when new evidence is found The current theory correctly explains the new evidence. The current theory does NOT explain the new evidence. What does this mean?

14 HYPOTHESIS In Science, Instead of theory scientists use the word Hypothesis to describe a possible explanation for a scientific question. It can be tested by comparison with scientific evidence that supports or rejects it. A scientific hypothesis must be testable! What does this mean? *It must be possible to collect evidence that proves whether the hypothesis is true or false. Not all hypothesis can be considered by science.

15 EXAMPLE It has been believed that creatures are alive because of an undetectable life force. Is this a scientific hypothesis? No, because there is no way to test it. If the life force is undetectable, that means that no evidence can be collected that would prove whether it exists or not. Science restricts itself only to those ideas which may be Proved or Disproved by actual evidence.

16 HELPFUL TIP If [I do this], then [this] will happen because of [this] i.e. If I increase the amount of fertilizer on grass plants, then the grass plants will grow taller, because plants will have more nutrients to grow taller provided by the fertilizer increase. In order to write a solid hypothesis, you also need to understand what your variables are for your project. It s ALL connected!

17 VARIABLES Independent Variable Is changed or manipulated by the researcher. They believe the I.V. might influence another variable. Presumed cause Dependent Variable The variable that is influenced by the independent variable. Responding variable Presumed effect i.e. (Time spent studying) causes a change in (Test Score) and it is not possible that a (Test Score) can cause a change in (Time spent studying).

18 ACTIVITY Which of the following Possible Scientific Hypotheses qualify as true Scientific Hypotheses? Remember: What qualifies as a Scientific Hypothesis? Get into groups and discuss amongst your groups if your example would be considered a valid Scientific Hypothesis. What are your variables? Rewrite your Possible Scientific Hypothesis as: If [I do this], then [this] will happen because of [this]