1 / 42

Scientific Method

Scientific Method. Steps in the Scientific Method. Observation Ask a question Gather information Hypothesis Experiment Conclusion Retest Theory. Observations. Gathered through your senses A scientist notices something in their natural world. Observations.

rskeen
Download Presentation

Scientific Method

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ScientificMethod

  2. Steps in the Scientific Method • Observation • Ask a question • Gather information • Hypothesis • Experiment • Conclusion • Retest • Theory

  3. Observations • Gathered through your senses • A scientist notices something in their natural world

  4. Observations • An exampleof an observation might be noticing that many salamanders near a pond have curved, not straight, tails

  5. Ask a question • Observations lead to a question that you would like to have answered. • Example: Why are the salamander tails curved?

  6. Gather Information • Research should be collected in order to help you find a possible solution to the problem. • For example: you might want to research salamanders, the environment in which they live, and make additional observations about the pond.

  7. Hypothesis • A suggested solution to the problem. • Must be testable • Sometimes written as If…Then… statements • Predicts an outcome

  8. Hypothesis • An example of a hypothesis might be that the salamanders have curved tails due to a pollutant in the moist soil where they live.

  9. Experiment • A procedure to test the hypothesis.

  10. Scientific Experiments Follow Rules • An experimenter changes ONE factor called a variable andobserves or measureswhat happens.

  11. Experimental Group • The group that contains the one variable that is being changed or tested is called the experimental group. • The group that does not include the variable being tested is called the control group.

  12. The Control Variable • The experimenter makes a special effort to keep other factors constant so that they will not affect the outcome. • Those factors are called control variables.

  13. What is the Purpose of a Control? • Controls are NOT being tested • Controls are used for COMPARISON

  14. Other Variables • The factor that is changed is known as the independent variable or manipulated variable. • The factor that is measured or observed is called the dependent variable or responding variable.

  15. Example of Controls & Variables • For example, suppose you want to figure out the fastest route to walk home from school. • You will try several different routes and time how long it takes you to get home by each one. • Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

  16. What are the Variables in Your Experiment? • Varying the route is the independent variable • The time it takes is the dependent variable • Keeping the same walker throughout makes the walker a control variable.

  17. One more thing… it is best to make several trials with each independent variable.

  18. Remember: To be a Valid Experiment: • Two groups are required --- the control & experimental groups • There should be only onemanipulatedvariable

  19. Data • Results of the experiment • May be quantitative (numbers) or qualitative

  20. Data • Must be organized • Can be organized into charts, tables, or graphs

  21. Conclusion • A judgement based on the data obtained from the experiment

  22. Retest In order to verify the results, experiments must be retested and hypotheses revised.

  23. Solving a Problem 1) Make Observations 1)Identify a Problem 2) Gather Information about the problem 3) Form a Hypothesis about the problem (if…then…) 4) Design an Experiment to test the hypothesis 5) Form a Conclusion 6) Retest 7) Form a theory

  24. Irma wants to know how UV Radiation affects cultures of bacteria. She sets up two groups. One group stays in the incubator, and one group stays under a UV lamp. Both groups are the same species of bacteria, grown on the same media, and are held at the same temperature. Independent Variable: Dependent Variable: Experimental Group: Control Group: Constants:

  25. Beverly wants to know how salt affects the boiling point of water. She boils two pots of water. In one, she adds a tablespoon of salt, and in the other, she puts nothing. She measures the temperature at which both pots boil. Both pots are identical.Independent Variable:Dependent Variable:Experimental Group:Control Group:Constants:

  26. Emily is testing a certain vitamin supplement to see if it will make her jump higher. She records her jump height with an electronic jump machine every day for two weeks. Then she takes two weeks off and begins the vitamin supplement. Then she continues the vitamin supplement and records her jump height every day for the next two weeks.Independent Variable:Dependent Variable:Experimental Group:Control Group:Constants:

  27. Susan wants to know if a new and improved brand of fish food will help her goldfish to grow faster. She divides her fish into two tanks. One tank of fish receive the new and improved brand of food and the other group receives the old brand of food. Independent Variable: Dependent Variable: Experimental Group: Control Group: Constants:

  28. Gene wants to know if a certain type of sports drink replenishes the number of electrolytes in athletes’ bloodstreams. He divides a group of athletes in half. To one half he gives Powerade sports drink, and to the other half he gives water. Thirty minutes after drinking their beverage, he draws blood and checks for electrolytes. All athletes were the same age and involved in the same activity prior to having their blood drawn. Independent Variable: Dependent Variable: Experimental Group: Control Group: Constants:

  29. Graphing in Science

  30. Bar Graph- used to compare data/quantities

  31. Circle/PieGraph- used to show percentages

  32. Line Graph- used to show a trend over a period of time or a relationship between two variables.

  33. Scientific Graphs • Most scientific graphs are made as line graphs. There may be times when other types would be appropriate, but they are rare. • The lines on scientific graphs are usually drawn either straight or curved. These "smoothed" lines do not have to touch all the data points, but they should at least get close to most of them. They are called best-fit lines. • In general, scientific graphs are not drawn in connect-the-dot fashion.

  34. Directly Proportional and Inversely Proportional Graphs Directly Proportional Inversely Proportional As the independent variable increases, the dependent variable increases as well. As the independent variable increases, the dependent variable decreases.

  35. Predicting Data on a Graph • Graphs are a useful tool in science. The visual characteristics of a graph make trends in data easy to see. • One of the most valuable uses for graphs is to "predict" data that is not measured on the graph. • Extrapolate: extending the graph, along the same slope, above or below measured data. • Interpolate: predicting data between two measured points on the graph.

  36. How to Construct a Line Graph • Identify the variables • Independent variable -Goes on the X – axis (horizontal) -Should be on the left side of a data table • Dependent variable -Goes on the Y – axis (vertical) -Should be on the right side of a data table 2.Determine the scale of the Graph • Determine a scale (numerical value for each square) that best fits the range of each variable • Spread the graph to use MOST of the available space

  37. How to Construct a Line Graph 3. Number and Label Each Axis a. This tells what the lines on your graph represent. Label each axis with appropriate units. 4. Plot the Data Points a. plot each data value on the graph with a dot. 5. Draw the Graph a. draw a curve or line that best fits the data points. b. Most graphs of experimental data are not drawn as “connect the dots”. 6. Title the Graph a. Your title should clearly tell what the graph is about. b. If your graph has more than one set of data, provide a key to identify the different lines.

  38. Graphing Practice Problem #1a Graph the data. What does the graph represent?

  39. Graphing Practice Problem #1b A. What type of motion does this graph represent? B. Put the data from this graph into a table.

  40. Graphing Practice Problem #1c Describe what happens during the time represented by this graph. B. Put the data from this graph into a table.

  41. Remember to: • ALWAYS label both axis, include UNITS. • Scale your axis numbers to use most of the graph, using the most appropriate increments. • Draw a best fit line. • Title your graph • Make a key for data if needed (more than one line on a graph)

  42. Quick Way to Remember how to build a Graph • D.R.Y. M.I.X. • This is an acronym for graphing • D-dependent, R-responding, Y-axis • M-manipulated, I-independent, X-axis

More Related