Ppt scientific method


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Ppt scientific method

  1. 1. • A logical, problem solving technique • A Step-by-step way in which scientists answer questions.
  2. 2. 1. Observation 2. Ask a Question 3. Background research 5. Design and conduct an experiment 6. Collect data 7. Analyze and Graph Data 8. Draw Conclusions 4. Formulate a hypothesis
  3. 3. • You observe something in the material world, using your senses or machines which are basically extensions of those senses. AH—Look at this!
  4. 4. • The problem identifies what you want to find out. State the problem in the form of a question: • Examples: Ex. Do bean seeds grow faster when fed compost or fertilizer? How does __________ affect _______? What is the effect of _______ on ________? Why” and “What would happen if..” are also good beginnings of scientific questions. • They must be testable: For example: Are Canaries prettier than blue birds? Not testable
  5. 5. Scientists never start from scratch in putting together a plan for answering a question. You should use library and Internet research to help you find the best way to do things and insure that you don't repeat mistakes from the past. • Background research is necessary so that you know how to design and understand your experiment and how to write a hypothesis. • Use a table with the "question words" (why, how, who, what, when, where) to generate research questions from your keywords. For example: When does a plant grow the most, with fertilizer or compost? What plants are most suitable for my experiment? How many plants must I use? • Plan to do background research on the history of similar experiments or inventions. • Ask other people with more experience than yourself: your parents and teachers.
  6. 6. • A hypothesis is NOT just an educated guess about what you think will happen. It must beTESTABLE!!!! a) Answers the observation and predicts an outcome of the experiment. b) “If… then… because” Statement c) If…..independent variable, then ….dependent variable Ex. If given compost, then bean plants will grow faster than those given fertilizer
  7. 7. • Experiment: a procedure to test the hypothesis • How are you going to test your hypothesis? • You Design an Experiment! • It must include: materials and a step by step instructions • Must be run multiple times
  8. 8. • An experimenter changes one factor and observes or measures what happens
  9. 9. CONTROL GROUP • The normal condition that you compare the other conditions to • Group not exposed to variable being testedused for comparison • Ex. Plant 1 is not given compost or fertilizer EXPERIMENTAL GROUP • Group exposed to variable being tested • Ex. Plant 2 is given fertilizer and Plant 3 is given compost
  10. 10. • A variable is something that can change, either naturally or on purpose. In an experiment it is a factor that is different from one group to another. • There are two types of variables: independent and dependant variables. • The factor that is changed is known as the independent variable. The factor that the scientist has changed in order to test the hypothesis (on purpose). It is the cause • The factor that is measured or observed is called the dependent variable. The result of what the scientist changed. It is the effect of what happened in the experiment.
  11. 11. The factor that the scientist has changed or manipulated in order to test the hypothesis (on purpose). It is the cause Ex. Amount of Plant 1, Plant 2, Plant 3
  12. 12. • The result of what the scientist changed. It is the effect of what happened in the experiment • It is measured in the experiment • Changes because of the independent variable • “Depends” on the independent variable Ex. Plant growth
  13. 13. • They are what the scientist kept the same in both the control group and the experimental group • Everything except the independent variable • Keeps the experiment ‘fair’ • Ex: type of plant, type of soil…
  14. 14. • 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. • 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.
  15. 15. • Write all measurements and results of the experiment. They may be quantitative (numbers) or qualitative • Be consistent when you are checking your experiments and recording the results • Use a table to organize your data in a chart with a title. – List your independent variable on the left side – Record your dependent variables on the right side • If you have more than one dependent variable, use a new column for each dependent variable
  16. 16. Example:
  17. 17. • Make the data table into a graph • Graphs make it easier to see patterns in the data. Graphs X-axis independent variable Y-axis dependent variable
  18. 18. Line Graph a. Used to show changes in dependent variable (plant growth) over time. b. Must have title, x-axis title (with units) and y-axis title (with units) c. Compare and look for trends and patterns using graphs example 5 10 15 20 25 30 35 40 45 50 55 0 1 2 3 4 5 6 Growth of Plant A Over Time Time (Days) PlantHeight(cm)
  19. 19. Bar Graph a. Use it when a set of measurements can be split into discrete and comparable groups b. To show the relative change between these groups. c. Must have titles and legend 0 1 2 3 4 5 6 Average Plant Growth over 50 Days Plant A (Control) Plant B (Fer- tilizer Added) Plant C (Compost Added) Plant A Plant B Plant C AverageGrowthinCentimeters
  20. 20. Pie Graph a. When showing parts of a whole..i.e. percentages b. Must have a title and a legend
  21. 21. • Indicate the results. Explain why those results where given. • Answer: – Do your results/data support your hypothesis? Why or why not? – What are ways you can improve your data? – What would you do differently if you were to repeat the experiment?
  22. 22. Claim a. Restate your hypothesis b. Ex. If given compost, then bean plants will grow taller than those given fertilizer. Evidence a. Accept or reject your hypothesis b. Use the numbers from your chart and graph to explain why. c. Ex. Plant C which was given only compost grew to a maximum height of 5 cm, Plant B which was given fertilizer grew to a maximum height of 4cm and Plant A which was given nothing at all grew to a maximum height of 3cm. Therefore, the hypothesis is accepted. Reasoning a. Scientifically explain WHY what happened occurred. b. Ex. Fertilizer contains only trace elements such as phosphorous, nitrogen and sulphur while compost contains decaying matter which can provide many complex organic nutrients for a bean plant. Therefore, the plant treated with compost grows taller.
  23. 23. • When you write you conclusion, you will be answering your research question, so make sure you discuss how it was answered. Also discuss your hypothesis, and if it was supported or not. Make sure to have a very clear statement of your final conclusion. • Did you prove it? • you cannot prove your hypothesis correct, you can only support it • make sure to discuss the data thatsupports your thinking
  24. 24. • Data, data, data • make sure to discuss the data, actually use numbers with units to discuss your findings refer to the table and graph to help support your thoughts • Research have you found information elsewhere to support your ideas? if so, then use a proper citation
  25. 25. • Your method probably wasn’t perfect, that’s ok, as long as you discuss the issues. There are two types of errors in your method, the first type is reliability. • Reliability according to Worthen is “The measure of how stable, dependable, trustworthy, and consistent a test is in measuring the same thing each time (1993). • Consistency did your method allow for a consistent set of data to be collected, or did the measurements change because of your method? • two people measuring the same thing differently is an issue with reliability • Measuring tools using poor tools to measure may affect reliability counting out loud is not a very reliable way to measure time, a stopwatch is much more reliable
  26. 26. • The second type of error in method is validity. Worthen describes a method as being valid in “the degree to which they accomplish the purpose for which they are being used” (1993). Meaning, does your method actually measure what you are trying to measure. • Proper variables make sure your variables are actually the correct ones to assess what you’re trying to investigate if you’re interested in health, is measuring someone’s weight the most valid measurement, or would BMI be better? • Proper tools make sure your measurement tool is the proper way to measure your variable if you want to measure the change in acidity, then blue-red litmus paper will not give you a valid set of data, you may need a pH probe
  27. 27. • A lab report MUST be written after every investigation. • A lab report contains the following parts: 1.Title 2. Introduction 3. Materials 4. Procedure 5. Results 6. Conclusions