SCIENTIFIC PRESENTATION

1. Scientific Presentations
How to (and how not to) Give an
Effective Scientific Presentation
Andrew Cornelius

2. Top ten fears of Americans
1) Public Speaking
2) Heights
3) Insects
4) Financial Problems
5) Deep Water
6) Sickness
7) Death
8) Flying
9) Loneliness
10) Dogs

3. Why do you need to speak?
 Publications lag 1-2 years behind discovery
 Talks at scientific meetings are current!!
 Your future job depends on talks
 You are evaluated by everyone as student
 Your talks reflect on advisor
 You will give candidate talks
 Interviewers make conclusions in first 3
minutes

4. Introduction

5. OUTLINE
• Introduction
• Experimental
• Results
• Discussion
• Conclusions
• Future Work

6. Outline
 Introduction
 Experimental
 Results
 Discussion
 Conclusions
 Future Work
 Don’t overuse “gee whiz
effects”
 Make sure material is
relevant
 Use simple backgrounds
 Use “normal” fonts
 At least 18 pt (24 better) –
this text is 20 pt
 Use “normal” colors
 Do not use red and green
as contrasting colors
 Only use for emphasis
 Check before using!!!
 Don’t use this outline!!!
 45 wasted seconds
Normal: 5
Red/Green
Color Blind: 2

7. Outline
 Before you start preparing your talk
 Know your audience
 Know the length of your talk
 Know the style of your talk
 Preparing the talk
 Choosing and organizing the content
 Preparing slides
 Don’t overdo methods part of talk
 Giving the talk
 Grab and hold audiences attention
 General information

8. Know your audience
 How large will the group be?
 Experts
 Eliminate introductory material
 Can be much more focused on the “interesting”
results
 Novices
 Assume your audience is intelligent but knows
nothing
 80% of material should be introductory
 Mixed
 Most difficult
 60% of material should be introductory

9. Length of talk
 12-15 minutes
 Contributed conference talks
 Most difficult!!
 Limit talk to 10 minutes
 Only make 2-3 points
 30 minutes
 Invited conference talks
 Journal club presentations
 Limit talk to 20 minutes
 60 minutes
 Invited talks
 Special seminars
 Limit talk to 50 minutes

10. Know the style of your talk
 Persuasive
 Instructional
 This talk!!
 Informative
 Normal for scientific meetings
 Formal or informal?
 Hard to time informal

11. Choosing and organizing the
content
 What are trying to tell audience?
 Tell them what you are going to tell them, tell them, tell
them what you told them
 2-3 points for 15 minute talks
 3-5 points for 30 minute talks
 4-6 points for 1 hour talks
 Write a basic outline
 Make a rough draft with slides
 Figure out how many slides you can use
 Slides without graphics should be up for at least 30 sec
 Slides with graphics should be up for at least 1 min
 Keep it simple, stupid!!!!!
 Cut what is not necessary

12. Preparing slides with text
 Use white or light color backgrounds
 Don’t use lists with more than 6 items
 Break into multiple slides
 Don’t use complete sentences
 Try to keep list items to 6 words or less
(unlike this one!!!)
 Don’t use abbreviations or acronyms

13. Preparing slides with graphics
 Graphics add to
viewer retention
 Try to avoid large
lists
 Keep graphics simple
 Use white or light
colored backgrounds
 10% of male
population color blind
 Make ALL text
readable
0 20 40 60
Recall (%)
Audience
Retention
Hear and See
See
Hear

14. Talking about human error
 Know your audience
 Intro physics students
 Know the length of your talk
 10 minutes
 Know the style of your talk
 Informative
 Choosing and organizing the content
 Space travel
 What are trying to tell audience?
 2-3 points for 15 minute talks
 Humans make mistakes
 Units are important
 Don’t “make” your answer agree with expectations
 Figure out how many slides you can use
 Try to limit to 2 slides with text (beginning and end) and 5 or 6 with
graphics
 Keep it simple (and interesting), stupid!!!!!

15. Human errors and space
program
 Space program driven by scientists
 Humans make mistakes
 Many disasters caused by human error
 Never forget units in your calculations
 Don’t “make” your answer agree with
expectations

16. Space Program Failures
 Project Mercury had a FORTRAN syntax
error such as DO I=1.10 (not 1,10).
 Gemini V 100mi landing error, program
ignored orbital motion around sun
 Atlas-Agena software missing hyphen;
$18.5M rocket destroyed
 Aries with $1.5M payload lost: wrong
resistor in guidance system
 NASA HESSI shake test 10 times too
strong, damaging spacecraft

17. Appollo 13
 Tank 2 Salvaged from Apollo 10
was accidentally dropped 2”
 Switch designed to run at 28 V
 Apollo 13 “upgraded” to 65 V
 Switch burned into open position
– O tank reached 1000° F and
1000 psi

18. Delta II spacecraft
 January 17, 1997
 $55 million dollar
rocket
 $40 million dollar
new generation GPS
satellite
 “Steering” error

19. Titan 4A spacecraft
 Second most
expensive accident
 August 12, 1998
 $1 billion ??? Payload
 Top secret
communications
intelligence satellite
 Battery power lost
momentarily
 Veered off course
 Intentionally destroyed

20. Space shuttle challenger
 Most expensive space
accident
 Jan 28, 1986
 $2B lost (along with
seven crew members)
 O-Ring failure (cold o-
rings didn’t seal and
were burned by H-O
mixture)
 Roger Boisjoly sent
memos out before

21. Approaching scientific problems
 Formulate problem
 Try to find solution
 Measure
 Carefully document findings (use units!)
 Compare expected value and result
 If different, why? (explore all options!)
 Computers don’t always give right answer

22. NASA: Human error caused loss of Mars orbiter
November 10, 1999
Web posted at: 2:25 p.m. EST (1925 GMT)
WASHINGTON (AP) -- Failure to convert English measures to metric values
caused the loss of the Mars Climate Orbiter, a spacecraft that smashed into the
planet instead of reaching a safe orbit, a NASA investigation concluded Wednesday.
An investigation board concluded that NASA engineers failed to convert English
measures of rocket thrusts to newton, a metric system measuring rocket force.
One English pound of force equals 4.45 newtons. A small difference between the two
values caused the spacecraft to approach Mars at too low an altitude and the craft is
thought to have smashed into the planet's atmosphere and was destroyed.
The board found that the error went undetected in ground-based computers. Also, the mission navigation's team had an
imperfect understanding of how the craft was pointed in space. Additionally, the mission navigation team, the report said, was
overworked and not closely supervised by independent experts.
The Mars Climate Orbiter was launched December 11, 1998, and began its long journey toward the red planet. Along the way,
engineers on the ground sent instructions to the craft to fire rockets to correct its path toward Mars. It was in these rocket firings that
the error occurred.
Illustration of the Mars Climate Orbiter
Mars orbiter

23. Conclusions
 Space program driven by scientists
 Humans make mistakes
 Many disasters caused by human error
 Never forget units in your calculations
 Almost all answers in physics use units!!
 Use SI units when possible
 Don’t “make” your answer agree with
expectations
 Mars orbiter could have been saved
 Computers are only as smart as the programmer

24. Why did I show this?
 Good example of choosing graphics to
enhance points
 Only tried to get across 3 points
 I placed at the 20 minute mark
 Average attention span of alert audience

25. Principles of an effective talk
 Communicate your arguments and evidence
 Persuade your audience that what you say is true
 Be interesting and entertaining
 Grab and hold audience’s attention

26. Why use
graphics?
 Picture is worth many
words
 In this case 700
 Color would enhance
 The medium allows
use of graphics
 Maximized retention
 5x higher with sight
and sound
 Properly cite material
Edward R. Tufte, The Visual Display of Quantitative
Information. Graphics Press (2001)

27. Making a decent figure
1940 1950 1960 1970 1980 1990 2000
0.01
0.1
1
Las Vegas
Washington State
Population
(millions)
Year
1940 1950 1960 1970 1980 1990 2000
0.01
0.1
1
Las Vegas
Washington State
Population
Bad Better

28. More on graphics
 Only use equations if
absolutely necessary
 If you use equations
 Slow down
 Talk through step by
step
 Explain relevence

29. Giving the best possible talk
 Make eye contact
 Don’t have nervous tendencies
 Pacing, bobbing, waving arms, jingling coins, etc.
 Hold pointer still
 Don’t point directly at overhead on projector
 Enunciate
 Make yourself slow down if necessary
 Avoid “uh”, “like”, “um”, “okay” etc
 Be enthusiastic
 Don’t block the screen
 Project as high as possible

30. Giving the best possible talk
(cont)
 Face the audience
 Do not read what is on your
overheads verbatim
 Never allow a blank screen to
flash by
 However, don’t leave a slide up too
long – put a black slide up if
necessary
 Try to relax
 Can be difficult
 Do NOT go over allotted time
 Don’t end with “I guess that’s it”
 Will get cut off at meetings

31. Know your material
 Practice, practice, practice
 Focus on communicating, not
performing
 Humor good, but this isn’t stand up
 Keep it simple
 Prepare key phrases
 Okay to write out material first
 Write down the point to make for each
slide
 If you don’t have a point, eliminate
slide!!!
 Stay on track
 Small digressions fine (shows you are
paying attention to audience)
It takes three
weeks to
prepare a
good ad-lib
speech

32. More advice
 Bring a copy of your slides if
giving a PowerPoint
presentation
 Fill the screen
 Don’t cover up portions of
overheads
 Don’t argue with questioners
 Practice, practice, practice
 Practice with slides
 Find someone to listen
 Record presentation
 Video
 Microsoft Producer

33. Conclusions
 Preparation is crucial
 Graphics enhance retention
 Be relaxed and (try to) keep audience
attention
 Finish on time
 The more you practice, the better you
will get

34. More material
 Go on Google and try “scientific talk” or
“scientific presentation”
 Physics Today articles
 ONR article
 10 Commandments to give a bad talk
 I will make this presentation available
on my web site