Geosciences Department

Presentation Tips

Modified after Cockerill and Wawrzyniec, 2001a and 2001b

Images in computer-based presentations

Copying and pasting images into computer presentation programs is unwise. This is because copied images are translated into a large-size, uncompressed image format that is native to the operating system, no matter what kind of file the original image was. For example, a 32 kB compressed JPEG image copied and pasted can become a 1119 kB uncompressed BMP image in Powerpoint. This greatly bloats the size of the ultimate Powerpoint file, and enormous files can cause presentation problems. In contrast, if the image is imported using the usual import button or menu item, the image remains in its original JPEG format and the ultimate Powerpoint file size remains small. The bigger and more complex the presentation file, the more likely there will be a problem. Keep things as simple and as small as possible.

Example: in a recent meeting I saw presentations that took several minutes to load, delaying the start of the talk and making everyone worried that the computer had crashed. These Powerpoint presentations had file sizes up to 400 MB for 15 minute talks, ten to forty times the size that they needed to be.

Key Elements in Preparing and Presenting a Talk

Delivering a talk is not the same as writing a paper and should not be treated as such. Remembering this one point will do wonders for any presentation. The following suggestions will help refine and enhance your communications skills.

Introduce, Inform, Conclude

In most introductory communication courses the teacher will instruct the class, “Tell them what you are going to tell them (introduction), tell them (body), and then tell them what you told them (conclusion).”

A typical introduction uses a grabber, such as a rhetorical question, a statistic, or a story to grab the audience’s attention. You should then clearly state in ONE sentence the thesis of the talk (e.g., I am here today to demonstrate that the wheel is most effective when patterned after a circle rather a square). Finally, in ONE sentence, state what the talk will cover. (For example, “This presentation will review wheel design and our wheel construction method, and will demonstrate why the circular design rolls better than the square design.”)

In the body of the talk, present your information in the same order, using transition statements between each point to review the point just completed and introduce the next. The body should include basic information about your research method and your results. A talk is not being peer reviewed nor is it likely to be the basis for reproducing your research. (How many abstracts did you cite in your last publication?) Therefore, unless your talk is about a new method or a study of a method (methodology), a one- or two- sentence summary is enough. The body of the talk should be delegated to presenting your findings, which should be the points you listed in your introduction.

The conclusion should repeat the main thesis statement and the primary points covered, then link back to the introduction, perhaps by answering the rhetorical question or finishing the story.

Keep It Simple

Narrow the talk to between two and four key points. Most studies conclude that people cannot mentally organize more than that during a presentation. A common mistake in scientific talks is to put several years of research detail into a 20-minute talk. It cannot be done coherently. Details should be left to written materials. Audience members who want more detail will contact you later.

Talk to Me

Your audience cannot go back and review what you said or stop and consult a dictionary for words that are unfamiliar. Use short words whenever possible, decipher acronyms clearly and slowly, and avoid jargon even when speaking to peers. Moreover, creating new terms should be left to manuscripts and should only be done when no other combination of terms is practical. Geology is an incredibly diverse discipline, and it is a mistake to assume that everyone who attends your talk has enough background to understand the jargon and the acronyms specific to your subfield.

Body Language Matters

Much of an audience’s response to you and your talk has nothing to do with what you say, but with how you say it. To ensure that the audience stays focused on what you are saying:

  • Look at the audience, not at the lectern, floor, or audiovisual screen.
  • If you are shaking, either do not use a laser pointer, or try to brace your arm on the lectern for stability.
  • If you use a pointer, put it down or turn it off when you do not need it.
  • Try not to hide behind the lectern.
  • Gesture and move naturally.
  • Avoid jewelry that clangs on the podium; the microphone will amplify the noise. This also applies to tapping your fingers or repeatedly shuffling note cards and papers.

Watch the Clock

Practice a talk more than once, and time it, before stepping in front of a lectern. Then, watch the clock while speaking. Regardless of how interesting your topic may be, going past your allotted time is rude to your audience and to other speakers. Remember that it is the job of the session chair to stop you if you go over time. A typical maximum rate of speech is about 100 words per minute, so a 15-minute talk should include no more than 1500 words.

Remember Murphy’s Law

Be prepared for equipment to fail:

  • Failure is relatively rare with modern computer software and hardware, but it happens.
  • Save your presentation in several different formats (e.g., ppt, pps, pdf) in case the main format fails to run correctly.
  • Carry a copy of these formats in a memory stick and/or write-once CD to your presentation, even if you already loaded your file at the speaker ready room.
  • Your primary file format should minimize the possibility of failure: we recommend pps (PowerPoint Show) as your primary file format.
  • Be prepared to talk entirely without your visual materials, or have backup presentation materials (e.g., overheads).
  • Complete power failures for projection equipment have happened. Have the presence of mind to proceed with your talk anyway, briefly describing the points of the visuals along with the other parts of the talk. Having practiced your talk several times previously helps enormously in this regard. Shutting your eyes can help to remove distractions. Speakers who pull this off can win considerable praise!

Computers and Presentation Software

Computing hardware and software can allow speakers to create highly versatile digital presentations. This can be a boon or a bane. On one hand, it allows for colorful, dynamic presentations that can be edited up to the last minute. On the other hand, such presentations are subject to two types of problems.

  1. Equipment or software failure. If the computer decides not to work for whatever reason, you need some kind of backup (see Murphy’s Law above). Note that complicated presentations are much more likely to fail than simple ones.
  2. Presentation design flaws. Because presentation software often includes wild color schemes, complicated canned templates, animation and transition effects, and sound effects, you have the opportunity to be creative. Unfortunately, presentation software generally has few or no guidelines on what works: what color combinations are easy on the eyes, what types of text or graphic elements reproduce well on screen, and how to arrange things to make your real points.
  3. In addition, fancy background patterns, transition effects, and other such rubbish will probably just distract your audience, and make it harder for them to extract your points and information from the background of colors, patterns, and effects.

Use the following guidelines when designing your next digital presentation.

Preparing Slides (any projected image) Using a Computer

General Rules

  • Make graphical elements AS LARGE AS POSSIBLE! Many presenters seem to think the audience wants to look at the broad blank borders of an image rather than the photos, maps, or graphs themselves. What are they thinking? If any graphical element is worth showing at all, it is worth showing at the largest possible size.
  • Do not use fancy backgrounds, gradients, sound, moving text, or any of the other distracting program features, unless you have a specific, carefully thought out, very good reason to do so, and then only use it as rarely as possible.
  • Backgrounds should be a single, solid color (e.g., dark blue), with contrasting text (e.g., white).
  • Images should be of modest resolutions. At present the typical computer projector has a resolution of 1024 x 768 or 1280 x 960. There is absolutely no point in creating images with higher resolution. Lots of high resolution images can slow or crash the projection program.
  • Avoid using patterns and screens; these can create Moiré effects when they interact with the projector pixels. Stick to solid colors or simple, large scale patterns.
  • Be brief and to the point on text slides; use an outline at most. Wordy introduction or conclusion slides distract your audience from the primary source of information: you. Use graphics to support your key points.
  • Keep figures and maps simple, as they are displayed for only a short time. The more complex the slide, the less useful it will be. Too many times we’ve heard speakers say, “I know this is busy but you only need to look at this tiny point.” The audience will not look only at the tiny point, but will try to decipher the complex visual, missing what you are trying to explain.
  • Consider humor in your presentation, but don’t go overboard.

Use of Color

  • Remember that a substantial fraction of a typical audience has difficulty distinguishing some colors (“color blindness”). For guidance on wise color choice, see here.
  • Use dark backgrounds and lighter lettering for most projected text.
  • Avoid using complementary colors (e.g., purple background and primary yellow text). Such combinations are eye catching, but may not appear sharp and can lead to eyestrain. If you like yellow text on a purple background, use a pastel shade rather than a bright primary yellow. It will be easier to read, which is the whole point. Avoid using broad areas of bright, primary colors in figures. The extreme contrast makes the figure “vibrant,” which distracts from the data.
  • Choose colors that minimize contrast but allow the text or lines to stand out. We’ve observed that digitally drafted slides work best with darker background colors and text and lines that are bright but complementary to the entire color scheme. Stick with earth tones and avoid primary colors except to emphasize some specific component of the entire slide.

Text Slides

  • Text size should be no less than 14 to 18 points and no more than 36 points. Anything outside this range will be too small to read or will overemphasize the BIG text.
  • Don’t use the drop shadow or other fancy text effects. These only make the text look blurry to most people.
  • Serif typefaces, such as Times or Palatino, have characters with stems (serifs) that can fade during projection. If you must use serif fronts, use BOLD to ensure that each character reproduces well. Your audience does not have much time to read your slides, so, as with content, keep the typeface simple.
  • Avoid dark lettering on dark backgrounds. The same goes for baby blue lettering on baby pink backgrounds – yes, it has been done; the offenders need not be mentioned by name. When in doubt use white on dark backgrounds and black on light backgrounds.

Maps and Figure Slides

  • Use pastels or earth tones to make up the largest areas on maps, and avoid complex patterns and fine lines. Maps convey a great deal of information; too much bright color and complex patterns strain the eyes or may be downright revolting, thus defeating the purpose. Your audience has only seconds to a minute or two to read your map; keep it simple and use bright colors to emphasize the important points, and they will remember more.
  • Use a line size of between one and four points. The most important lines in the figure should be the thickest. Use dashed lines only where absolutely necessary.
  • Avoid placing text over lines. Unless you mask out the line, the text is hard to read.
  • Use color to differentiate sets of data represented in a single graph. The convention of using different shapes defeats the flexibility of using color, and they symbols are often hard to differentiate.


  • Keep slides simple, text sparse, illustrations large.
  • Practice several times, timing yourself.
  • Be prepared for technological failure with alternative file formats and media in your pocket, and be resolved to continue even with no slides at all.
  • With a little work and thought, you can actually build a reputation as a first-rate presenter.

Source of the original material:

Cockerill, K and Wawrzyniec, T.F., 2001a, When presentations go bad: a commentary – Part I: GSA Today, v. 11, no. 2, p. 12-13.

Cockerill, K and Wawrzyniec, T.F., 2001b, When presentations go bad: a commentary – Part II: GSA Today, v. 11, no. 3, p. 24-25.