Barista Camp 2015 | Christopher Hendon - Performing a good experiment

Chris introduces us to the act of performing a good experiment with four clearly recommended steps. Highlighting potential failures on the way and using the audience to demonstrate how to conduct a basic statistical experiment, the viewer can feel confident that Hendon's science background is serving us well. Closing his talk with the proclamation that he has no vested interest in the business of coffee and is motivated by wanting everyone to ‘make better coffee’, we hope he sticks around!

Transcript

1. Performing a good experiment Christopher H. Hendon Department of Chemistry Massachusetts Institute of Technology hendon@mit.edu
2. Boston, Massachusetts, USA 84 Nobel Laureates over the years Ranked #1 university in the world
3. Some MIT inventions 1.  The World Wide Web (Tim Berners-Lee) 2.  Email (Ray Romlinson) 3.  The Transistor Radio (William Shockley) 4.  Oil Refining 5.  Gillette Razors 6.  GPS (Ivan Getting) 7.  E-ink (now found in the kindle) 8.  Human Genome Project
4. •  Learn to ask a good question •  Determine dependent/independent variables •  Design and execute experiment •  Analyze data Experimental Science
5. •  Learn to ask a good question •  Determine dependent/independent variables •  Design and execute experiment •  Analyze data Experimental Science
6. A good question has many important features –  What are we trying to figure out? What can we currently not explain –  Why are we trying to figure this out? What can we gain from exploring this problem –  Does the question have an answer? A ‘Yes’ and ‘No’ must be distinguishable –  Do we have the ability to answer it? Cost and expertise associated with the answer Asking a good question
7. •  Learn to ask a good question •  Determine dependent/independent variables •  Design and execute experiment •  Analyze data Experimental Science
8. Some variables can be directly modulated, others are implicitly affected by this change. e.g. Flow rate of water through a group head vs. % mass extracted (using a refractometer) Easiest ‘trick’ to identifying variables is to simply try and draw a graph The variables
14. •  Learn to ask a good question •  Determine dependent/independent variables •  Design and execute experiment •  Analyze data Experimental Science
15. We want our experiments to contribute towards an ‘end goal’. Any individual experiment does not give the full story. Think big, test small
16. •  Learn to ask a good question •  Determine dependent/independent variables •  Design and execute experiment •  Analyze data Experimental Science
17. Conclusions are only ever relative. You can ‘see what you want’ in the data. Data Analysis: It’s not personal
18. The Birthday Paradox Two assumptions: All birthdays are equally probable Everyone tells the truth Listen to each other. The birthday paradox
19. Outcome: Does this mean that 2 / __________ people have a birthday on ____________? No. Statistical sampling is tricky stuff! The birthday paradox
20. 50% probability with 23 people 99.9% probability with 70 people
21. You must try and fault yourself
22. % Particle Diameter (µm) Make sure you check the fine details •  EK-43 grinding Las Ilusions: Volume %
23. % Particle Diameter (µm) •  EK-43 grinding Las Ilusions: Volume % (dotted line is Surface area %)
24. % Particle Diameter (µm) •  EK-43 grinding Las Ilusions: Volume % (dotted line is counts in %)
25. % Particle Diameter (µm) Make sure you check the fine details % GOOD DATA BAD DATA
26. Not all EK-43’s are the same (…sorry Christian)
27. Dangerous to conclude information from data that has not been appraised by other specialists with no financial conflicting interests. There is no peer-review in coffee
28. An Idea: The Coffee Experiment To elucidate the difference in extraction of Ethiopian versus Kenyan coffees.
29. An Idea: The Coffee Experiment When you have BOTH Ethiopian and Kenyan coffee Dial in one of the coffees to whatever ratio you think tastes delicious. Then brew the other coffee with the exact same parameters and measure the extraction with a refractometer.
33. Visit my website
34. Christopher H. Hendon
35. Christopher H. Hendon
36. Comments, Questions, Criticism