Hypothesis-Based Science The Scientific Method

Science as Inquiry The process of investigation to answer questions about the natural world

Discovery Science Emphasizes Inquiry and Observation Discovery Science –Describes natural structures or processes as accurately as possible through careful observation and data collection - Jane Goodall Inferences in Science –Logical conclusions based on observations –They help to refine general questions into specific questions Generalizations –General conclusions put together from many specific observations **Generalizations describe patterns. There will be exceptions to those patterns.** –Ex. - the cell theory; girls stop growing before boys; it is always dark at midnight

The Scientific Method An organized way to solve a problem through experimentation & observation.

The Steps of the Scientific Method

1. State the Problem Form a question about a specific event or reaction Examples: –Does soap kill plants? –What type of food do goldfish prefer?

2. Collect Information Research the problem –Internet –Scientific Papers

Other Ways to Collect Information Observation- the act of observing (touch, taste, smell, feel, see, etc.) –Direct –Indirect Inference- a quick, logical conclusion that attempts to explain an observation and helps refine a general question into specific questions for study

Observation vs. Inference ObservationInference The doorbell rang.Someone is at the door. Mom saw me sneaking out. I’m going to get grounded.

3. Form a hypothesis Make an educated guess based on your research. Hypothesis- a tentative explanation that accounts for a set of facts & that can be tested by further investigation Examples: –Plants exposed to soap will die. –Fish prefer Miller brand flakes. A hypothesis must be: –TESTABLE (able to be tested) –FALSIFIABLE (able to be proven false)

Making Predictions Prediction- to forecast; to guess the outcome of a situation beforehand Often an “if…,then…” statement that explains what will happen if the hypothesis is correct. IF: state the variable you will change to test the hypothesis THEN: state what you think will happen Examples: –If I water plants with soap water, then the plants will die. –If I feed the fish different foods, then they will eat more of the Miller brand flakes.

4. Design an Experiment Devise a way to test your hypothesis. Create aCONTROLLEDexperiment. Controlled Experiment- an experiment in which all variables except the ONE being tested are identical in order to make the experiment fair & the results reliable

A controlled experiment MUST have 2 groups. CONTROL GROUP: all conditions remain the same EXPERIMENTAL GROUP: only the condition that you are testing for is changed ONLY 1 condition is changed!

Establish the variables for your experiment. Variable- any factor in an experiment that could affect the results & is therefore tested separately INDEPENDENT VARIABLE: the variable that is changed, purposely manipulated (manipulated variable; X axis for graphing) DEPENDENT VARIABLE: the variable being observed that changes in response to the independent variable (responding variable; Y axis for graphing) CONTROLLED VARIABLE: the variable that is not changed

5. Collect & Analyze Data Run the experiment & document the data We make observations using our senses to collect and analyze data. Technology can also assist us in collecting and analyzing data. Data- recorded observations or measurements –Data Should Be: Clearly organized Recorded at consistent intervals Reliable

Data Types Quantitative Data- data that involves numbers or measurement usually in the form of a chart or graph Qualitative Data- anecdotal or descriptive data that does NOT involve numbers or measurement

QUANTITATIVE: numerical data, deals with specific quantities, usually in the form of a graph or chart QUALITATIVE: descriptive data, describes how something looks, smells, sounds, or feels; deals with qualities

6. Draw Conclusions The data will either SUPPORT or CONTRADICT the hypothesis (Never use “prove”) Conclusion- to close or bring to an end; to accept or reject a hypothesis in an experiment

Consider Sources of Error Sources of Error – anything that could affect the outcome of the experiment “I measured wrong” is not an acceptable source of error Examples: –One of the plants was sick –One of the plants received more light than the others

Communicating Results Scientific discoveries must be communicated to other scientists to be scrutinized. Ways to communicate: –Peer-reviewed journals –Scientific conferences –Internet

Communicating Results Other scientists must be able to: –Evaluate your data for errors –Repeat your experiment –Obtain similar results Science values skepticism ***This is why communication is critical!***

Scientific Models Model – a representation of how we understand a process or idea Can be: –Physical –Mental –Mathematical Helpful to understand difficult concepts

Progression of Ideas in Science Hypothesis- a possible explanation to a question based on information the scientist has already gathered - If experiments show a hypothesis to be correct, other scientists may accept it as support for a scientific theory. EX: Plants obtain their energy from the sun.

Progression of Ideas in Science Scientific Theory- a general statement of why things work based on hypotheses that have been tested many times; an explanation of a large body of information, experimental and inferential, and serves as an overarching framework for numerous concepts. It is subject to change as new evidence becomes available.

Progression of Ideas in Science - Theories are used to explain & predict the outcome of other experiments - Theories must be tested - Sometimes they are wrong & must be modified or discarded EX: The Earth is flat.

Progression of Ideas in Science Scientific Law- a statement of what happens in a certain event based on verified observations & experiments; a basic scientific theory that is no longer tested & is generally accepted as true

Progression of Ideas in Science - Explains what happens & not why EX: Newton’s Law of Gravity - Summaries of the results of many, many experiments & observations - When results of a series of experiments are the same each time that they no longer need to be tested

Progression of Ideas in Science Which one is most likely to be wrong- hypothesis, theory, or law? HypothesisTheoryLaw

Limitations of Science Although science is a “way of knowing”, it is not the only way –Ex. How do you know if you like a certain song? Science CAN address natural explanations for natural phenomena Science CANNOT address things such as personal preference or the supernatural

Technology Science – understanding through observation and experimentation Technology – the application of science for a purpose Examples: –Computers –Genetic engineering of foods to make them pest-resistant –Medical applications