Experimental design graphing
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Experimental design graphing






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Experimental design graphing Experimental design graphing Presentation Transcript

  • Experimental Design/Graphing
  • Scientific Inquiry• Ask questions• Gather information from many sources
  • Scientific Explanations/Theories• Constructed using evidence that can be observed – Understanding the history of scientific development helps scientists further their research and knowledge
  • Experimental Design Words to Know• Observation – noticing details; recording information• Inference – drawing conclusions based on facts or observations• Theory – an idea attempting to explain a group of observations
  • Hypothesis• Prediction based on research and observation• Guides scientists how to design experiments• Data analysis leads to the development of more hypotheses and additional experiments
  • Making a Research Plan• Before scientists do anything: sufficient background information is needed to ensure a thorough understanding of a topic• Methods and Procedures List• Safety – In regard to biological research, it furthers our knowledge of how to diagnose, prevent, treat, and cure disease
  • Graphing1. Bar Graph – Used to compare amounts or frequency of different categories of data – Ex: different types of birds in an environment
  • Graphing2. Line Graph – Used to show a relationship – Change over time, changes according to different temperatures – Ex: How weight changes over time
  • When making a graph…• Make sure:1. The scales are equally divided – Make sure the difference between each number on the scale is EQUAL (ex: 0, 10, 20, 30…) – Must take up 75% of axes2. Must start at zero OR use a scale break
  • Independent vs. Dependent Variables• Independent Variable – Changes independently – The “thing” being tested Ex: time, temperature, day of the week, light intensity• Dependent Variable – Changes BECAUSE of the independent variable – DEPENDS on the independent variable Ex: plant growth, population growth
  • Independent vs. Dependent Variables Ask: Does ______________ depend on ________________? *If yes, then the first blank is the dependent variable because it DEPENDS on the other variable! Try it on an experiment measuring plant growth vs. light intensity: Ask: Does plant growth depend on light intensity? YES! So plant growth is the dependent variable. Ask: Does light intensity depend on plant growth? NO! So light intensity is NOT the dependent variable.
  • Controlled Experiment• Experimental Group – the group that receives treatment (independent variable) – ex: Plants that get light• Control Group – group that does not receive treatment; group that gets placebo; group that is compared to – Ex: Plants without light treatment
  • Controlled Experiment• Placebo – Sugar pill; Fake treatment; Given to the control group Ex: Testing a medication – one group gets sugar pill, one group gets medication• Subjects – People or objects being tested• Sample Size – Number of subjects tested
  • Characteristics of a Good Experiment1. Can be repeated by anyone and to get same results2. Has large sample sizes (tests many subjects)3. Performed over a long period of time4. Tests only one variable5. Peer Reviewed – examined by other scientists to determine its accuracy6. Does not have to agree with the hypothesis; scientist can be incorrect7. Is objective – conclusion must be FAIR and UNBIASED; scientists’ opinion is not a factor8. Significant results can support hypothesis
  • Scientific Explanations• Are subject to change! – Ex: The world was first thought to be flat• Lead to more questions – The best theories are those supported by many different types of research
  • While Mendel was doing research with peaplants, he saw that 75% of offspring resultingfrom a cross produced green pea pods. Which ofthe following choices describes the previousstatement?1. a conclusion2. an observation3. an inference4. a hypothesis
  • One scientist reported breeding successbetween a horse and a mule. Other scientistswould accept these results as factual if1. research shows that other animals can breed selectively2. the offspring did not die after birth3. the scientist cited his sources4. other researchers can replicate the experiment with the same results
  • A student sets up an experiment investigatingthe effect of light intensity on tomato plantgrowth. In this experiment, the ____________is the independent variable and the_____________ is the dependent variable?1. Light intensity; tomato plant growth2. Tomato plant growth; light intensity3. Tomato plant growth; the student4. Light intensity; the student