如何做一個優美的幻燈演示？很復雜的一個命題，如果真說起來，可能一個月都說不完。但是一個優美的幻燈還是有章可循的。ERIN BEDFORD 有一文講的不錯。

Love it or hate it, PowerPoint is everywhere. 「Preparing a presentation」 has become synonymous to 「preparing a PowerPoint presentation」, but is this really a good attitude when it comes to communicating research? PowerPoint is a tool, and as with any tool, its true power comes not from the tool itself but from the one who holds it. Like dynamite, handled properly it can blast through the mountain that is communication between presenter and audience, but placed in the wrong hands and the audience may end up buried in the rubble.

I recently attended a great talk on the subject, which has got me thinking about presentations. What are the dangers of PowerPoint, how can we avoid them, and how can we make sure to keep focus on the content rather than the medium?

Identify your audience

Know your audience. Without them, there is no presentation. When presenting to a group of experts in your field, skip over the in-depth intro and focus most of your slides on the knitty-gritty details; when presenting to a group of first-year chemistry students, do the opposite. But it’s not always this easy. What about mixed audiences? For example, I gave a short talk last month to a group of graduate students in materials science, which is so broad a field that many were not at all familiar with my subject. On the one hand, I wanted everyone in the audience to be able to understand my work; on the other hand, one of the goals of the series of talks was to find solutions to research problems we might be having, so it was important to present the details of my research. With only 10 minutes to talk, I couldn’t do both, so I had to identify who in the audience I wanted to present to. In this case, I decided that if I wanted tips from those in my field, I would have to present my results in detail, so I prepared a presentation with a brief introduction and focused more on my results. Many conferences are multidisciplinary, so choosing who in the audience you want to direct your talk to is an important first step in preparing a presentation.

聽眾人群不同，幻燈演示的方法也不同。

比如聽眾是專家級別的，就可以忽略徹底的介紹，而著重于詳細的細節問題。如果是為學生做演示，那么就應該相反，應該重點介紹一下現狀，而忽略一些細節問題。

但是有時情況可能更復雜，聽從水平參差不齊，此時應該了解聽眾的需求。是想知道我所做的工作還是想了解我對于問題的解決方法。需求不同，展示的方式也就不同。

A presentation is not a paper

Rarely do we read a journal article linearly. We read the abstract, look at the tables and figures, glance at the conclusion, then maybe go back and read the rest. Because of this, journal articles are written in a predictable way, conducive to this jumping between sections (and online formats are making this even easier). Methods are separate from results, even when there are multiple steps involved.

With a presentation, you’re forcing the audience to follow you in a particular order, so make sure that the order makes sense. The linearity of a PowerPoint presentation means that the audience can’t make the same abstract connections that they can when reading a paper; by the time they’ve registered one concept, you’ve moved on to something else. Keep similar ideas together to reduce the need for remembering. This might mean that there is no methods section, but rather methods are discussed at the same time as their corresponding results. It also might mean that you repeat information or show the same graph twice if needed. Another useful tip is to use informative titles; rather than titling a slide 「Results」, use descriptive titles like 「A increases B」. This can provide a quick catch-up point for audience members who are still thinking about the previous slide.

當我們閱讀論文時，很少是從頭讀到尾的。一般是先看一下摘要，文中的圖表，瀏覽一下結論。如果認為該文值得一讀，可以閱讀剩下的部分。具體閱讀方法可以參閱此文：如何選擇和閱讀科技論文。

但是幻燈演示不同。幻燈演示的時候不可能強迫聽眾跟著你的節奏來。因此幻燈演示的時候應該重點突出，有時對于重要的內容，可以重復。

Keep it simple and clear

There’s no point in using slides if no one can read them. Use big fonts, clear images, contrasting colors, motion only when it serves a purpose… There are numerous sites that give tips on the design aspects of a PowerPoint presentation; to start, check out the amusing Death by PowerPoint or one of Lifehackers’s posts on the subject. You don’t have to be a graphic designer to put together a good presentation. By taking some time to think about the clarity of your slides, the audience will be grateful.

盡量減少文字，使用不同的字體、顏色和圖表表達一個主題。

PowerPoint is meant to complement, not be, a presentation

PowerPoint has made us lazy. It’s too easy to put what we want to say on a slide and read it while the audience looks at the pretty pictures instead of focusing on the presenter. While having visuals associated with a presentation can be extremely useful, we don’t attend talks to look at data and read conclusions. Everything that is on a slide should be there only to help the audience understand what is being said. When planning on leaving a handout for interested audience members, prepare a separate handout that includes the necessary detail rather than trying to put everything on the slides. Or as another option, record your presentation and put it online.

PowerPoint is everywhere, and it’s not going away anytime soon. Used properly, it’s an excellent tool for conveying the complex information we deal with in research. But a bit of kindness towards the audience will go a long way－they’ll be more interested and our fascinating research will be remembered.