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What do I mean? Issue trees Hypothesis trees Experimental design

What do I mean? Issue trees Hypothesis trees Experimental design. Dr. Matthew Juniper, CUED. Hypothesis-driven and Investigative Experimental Design. What do I mean?. Hypothesis-driven and Investigative Experimental Design. Investigative. Experiments. Hypothesis-driven. Examples.

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What do I mean? Issue trees Hypothesis trees Experimental design

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  1. What do I mean? Issue trees Hypothesis trees Experimental design Dr. Matthew Juniper, CUED Hypothesis-driven and Investigative Experimental Design

  2. What do I mean? Hypothesis-driven and Investigative Experimental Design Investigative Experiments Hypothesis-driven

  3. Examples Millikan's oil drop experiment to determine the charge on the electron (1909) Investigative Experiments Hypothesis-driven

  4. Millikan's oil drop experiment (1909)

  5. Millikan's oil drop experiment (1909) Charge on the electron = 1.592 x 10-19 Coulombs

  6. Millikan's oil drop experiment (1909) Charge Charge on the electron = 1.592 x 10-19 Coulombs 1909 Year

  7. Millikan's oil drop experiment (1909) Charge 1.602 x 10-19 Charge on the electron = 1.592 x 10-19 Coulombs 1909 Year

  8. Examples Millikan's oil drop experiment to determine the charge on the electron (1909) Investigative Michelson-Morley experiment to determine the speed of the earth through the Aether (1887) Experiments Hypothesis-driven

  9. Michelson-Morley experiment (1887)

  10. Michelson-Morley experiment (1887) Speed of the earth through the Aether = .... very small !

  11. Examples Millikan's oil drop experiment to determine the charge on the electron (1909) Investigative Michelson-Morley experiment to determine the speed of the earth through the Aether (1887) Experiments Hypothesis-driven

  12. Examples Millikan's oil drop experiment to determine the charge on the electron (1909) Investigative Michelson-Morley experiment to determine the speed of light in different reference frames Experiments Light travels at the same speed in any frame of reference Hypothesis-driven

  13. What do I mean? Issue trees Hypothesis trees Experimental design Contents Hypothesis-driven and Investigative Experimental Design

  14. Issue trees Issue Tree What ? or How ? Sub-issue 1a Issue 1 Sub-issue 1b Sub-issue 1c Sub-issue 2a Open question Issue 2 Sub-issue 2b Sub-issue 2c Precise issues can be tested by hypothesis Precise issue Sub-issue 3a Sub-issue 3b Issue 3 Sub-issue 3c Issues are independent and complete

  15. Issue trees – an example What ? or How ? What can we do about climate change ?

  16. Issue Tree applied to an engineering problem What ? or How ? composition oxidant temperature pressure reactant properties composition fuel temperature the state of the fuel / air mixture in each burner pressure pilot / main flame configuration burner face flow shear at injection point aero-dynamics position of cooling air down-stream velocity of cooling air the introduction of energy to the fuel / air mixture in each burner What influences the re-light and light-round characteristics of an aeroplane engine type of spark burners position of spark energy of spark duration of spark spark timing of spark The distance between burners the design of the network of burners in the engine Axial view of combustion chamber in an aeroplane engine The order in which they are turned on

  17. What do I mean? Issue trees Hypothesis trees Experimental design Contents Hypothesis-driven and Investigative Experimental Design

  18. Hypothesis trees Why? Tertiary hypothesis 1a Secondary hypothesis 1 Tertiary hypothesis 1b Tertiary hypothesis 1c Tertiary hypothesis 2a Primary hypothesis Secondary hypothesis 2 Tertiary hypothesis 2b Tertiary hypothesis 2c All hypotheses must be precise statements Tertiary hypothesis 3a Secondary hypothesis 3 Tertiary hypothesis 3b Statement 3c(i) or Tertiary hypothesis 3c Statement 3c(ii) All the secondary hypotheses must be true for the primary hypothesis to be true

  19. Hypothesis trees - example Why? I can make money by blackmailing someone.

  20. Hypothesis trees - example Hypothesis 1.4 Conv. Unst. flame amplitud\e of response amplitude of forcing signal Abs. Unst. flame amplitud\e of response amplitude of forcing signal

  21. Hypothesis trees - example Hypothesis 1.4 Experimental results Conv. Unst. flame amplitud\e of response amplitude of forcing signal Abs. Unst. flame amplitud\e of response amplitude of forcing signal

  22. What do I mean? Issue trees Hypothesis trees Experimental design Contents Hypothesis-driven and Investigative Experimental Design

  23. Application to experimental design • 1. Start with an issue tree (ask 'what?' or 'how?') e.g. • What questions do I have? • What do I want to show? • What is my PhD about? What ? or How ? 2. For each sub-issue, think of an investigative experiment. Then ask 'so what?' – does this tie in with a theory? So what ? 3. For each relevant sub-issue, develop a hypothesis tree (ask 'why?' or 'what has to be true for this hypothesis to be true?') Develop the analysis to test the sub-hypotheses. Why?

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