Nature of Science/Scientific Method Unit 1, Notes

What Is Science? The goal of science is to: investigate and understand the natural world explain events in the natural world use those explanations to make useful predictions In short, science is an organized way of using evidence to learn about the natural world.

Questions to Consider ANSWER… THE SCIENTIFIC METHOD! How can we determine if something is fact or opinion? How can we determine an answer to a problem? ANSWER… THE SCIENTIFIC METHOD!

Step 1 Ask a Question - define the problem - make sure only one problem is being studied based on your observation - observations are made by using your 5 senses touch taste smell sight hearing

Step 2 Research the problem use all available resources to collect data on the subject being covered. Ex: library, internet, books, magazines, interviews, etc.

Step 3 Develop a Hypothesis -- educated guess make it a short and definitive statement it should be in “If….” “Then….” format the “if part” is the hypothesis the “then part” is what you think the results will be at the end of the controlled experiment. a hypothesis can be changed.

Step 4 Develop a Controlled Experiment contains only one experimental variable, known as the manipulated variable. I.E. the thing being tested Everything else in the experiment or all other variables must be the same. called constant variables keeping these the same allows the scientists to show that it was the experimental variable that caused the results.

Variables in a Controlled Experiment Manipulated Variable: the variable you are testing; also called independent variable Control Set-Up: what you compare to, no manipulated variable used Responding Variable: variable you measure; changes in response to the manipulated variable Constant Variables: consistent between all trials

Step 5 Record and analyze the data the data may or may not support the hypothesis. if the data proves the hypothesis wrong, change the hypothesis, not the data. if the data supports the hypothesis, additional experimentation must then take place to build documentation to support the hypothesis

Types of Data Quantitative Data - expressed as numbers - obtained by counting or measuring - Ex: 50 ml, 800 km, 45 sec Qualitative Data - descriptive - Ex: clear, spherical, smooth

Step 6 Draw A Conclusion - use the evidence to support or refute the hypothesis - a proven hypothesis must stand up to additional testing - other scientists repeat each others investigations

Step 7: Peer Review Scientist will share findings and collaborate with other scientists. Other scientists MUST be able to replicate the experiment and get the same results.

Example: Ask a question, identify problem: Is Raid the best insecticide on the market? Research: Look up information on insecticides , what are the active ingredients, how many insects will it kill, how much does it cost, etc.. Hypothesis: Raid is the best insecticide on the market. It will kill insects 30% faster than other insecticides.

Experiment: Spray 5 plates with equal amounts of 5 different insecticides. Cover each one with the same type and size of glass. Add equal numbers of the same species of insect to each plate. Place the plates side by side. Time the results Observe and record the number of insects that die.

Collect data and analyze: This is done by writing down the # of insects that died or how fast they died and then organizing that information into a graph so you can better see what happened in the experiment. Conclusion: This is done after the data from the experiment has been collected and analyzed. In this step you will find out if you were correct and Raid was the best or if your hypothesis was rejected!

Different Types of Scientific Investigations Descriptive, Comparative and Experimental Investigations

Comparative Investigations involve collecting data on different organisms/objects/ features/events, or collecting data under different conditions (e.g., time of year, air temperature, location) to make a comparison. The hypothesis identifies one independent (manipulated) variable and one dependent (responding) variable. A fair test can be designed to measure variables so that the relationship between them is determined.

Experimental investigations involve designing a “fair test” similar to a comparative investigation, but a control is identified. The variables are measured in an effort to gather evidence to support or not support a causal relationship. This is often called a controlled experiment. A fair test is conducted by making sure that only one factor (variable) is changed at a time, while keeping all other conditions the same.

Descriptive Investigations Descriptive investigations involve collecting qualitative and/or quantitative data to draw conclusions about a natural or man-made system (e.g., rock formation, animal behavior, cloud, bicycle, electrical circuit). A descriptive investigation includes a question, but no hypothesis. Observations are recorded, but no comparisons are made and no variables are manipulated