Haim Weizman is a chemist by trade and an Internet moviemaker on the side.

In his first video, a telegenic narrator in a lab coat swirls a flask as electronic music plays in the background. Created by four science and film students at the University of California at San Diego, the video shows a typical recrystallisation experiment straight out of Chemistry 101.

The six-minute epic complete with bloopers got 1,205 views on Google's YouTube, but the number increased fourfold when the video was posted to SciVee, one of a number of online video-sharing startups designed to let scientists broadcast themselves toiling in the laboratory or delivering lectures.

Fans of the niche sites say they help the lay public — and students — understand the scientific process, allow researchers to duplicate one another's results and may help discourage fraud.

"Anyone in an organic chemistry class anywhere can now perform this experiment by watching the video. There are so many details that it's hard to describe in a lab manual," said Weizman, a lecturer at UC San Diego. He went on to produce five more lab-training videos.

Researchers who are uploading their experiments and lectures online are discovering filmmaking is more art than science. If the narrators are boring or the image is shaky, viewers will quickly learn to click elsewhere.

"Scientists are not moviemakers so getting them to shoot their experiments and describe them properly can be a challenge," said Anton Denissov, a broadband video analyst with the Yankee Group.

Funded by the National Science Foundation, SciVee encourages scholars with a paper hot off the press to make a short video called a "pubcast" highlighting the key points. It also accepts unsolicited submissions that have no connection to any published work.

Phil Bourne, a pharmacologist at UC San Diego, launched SciVee this summer after seeing his students hooked on YouTube. Bourne wanted a reputable virtual place where researchers could trade techniques without the potpourri of topics found on general video-sharing sites.

"It's quite a quantum leap for scientists to present their research in this way," Bourne said.

The age-old practice of reporting scientific results in peer-reviewed journals or at scientific conferences isn't going away soon. Most journals with online editions are taking a wait-and-see approach about YouTube-type videos, although many routinely add podcasts and other media to accompany papers.

"This is an area we're extremely interested in, but we're still in the embryonic stage," said Stewart Wills, online editor of the journal Science.

One of the startup sites — called JoVE, short for the Journal of Visualized Experiments — is the digital mirror to traditional scientific journals, however.

Created last year by a former Harvard postdoctoral student with help from an angel investor, the site has stringent publication rules. On the recommendation of its editorial panel, it dispatches professional videographers to labs around the world doing interesting work. Their footage is edited and approved by the researchers before being posted.

JoVe Editor-in-Chief Moshe Pritsker said the Web site grew out of "personal pain." For most of his academic career, he was flustered by what he called the "black hole" of science: Despite attempts by well-intentioned scientists to explain their experiments on paper, some procedures are so complex to mimic that a person must physically explain them.

Pritsker said he once flew to Scotland for a week when he was a Ph.D. student just to see how a research group performed an embryonic stem cell technique. He couldn't help but wonder if there were an easier way than jetting across the Atlantic Ocean to reproduce a two-hour procedure.

"We need to show our experiments and show in our age means video," Pritsker said.

The popularity of JoVe inspired Siddharth Singh, a computer science graduate student in India, to start a site in March called LabAction, which focuses on sharing biological techniques. Another site, called DnaTube, was launched in January by Nazir Okur, a molecular genetics graduate student at the University of Illinois who encourages scientists to upload videos of their studies, lectures and seminars.

Some experts say the biggest advantage to science videos is making research more accessible to non-scientists. There's no guarantee that video can't be manipulated, but the medium also may force scientists to think twice before committing fraud.

"It's one thing to put your name on a fake paper and it's another to make a fake video that your friends and family could watch," said John B. Horrigan, associate director for research at the Pew Internet & American Life Project.

Last year, Horrigan authored a study that found more than half the people who seek science information online want to hear it from the original source.

Translating the experiments to video won't be without challenges. Chief among them is attracting enough Web traffic to make the sites profitable. Even combined, the science video sites attract an extremely small group compared with the hoards who flock to YouTube, which drew 48.5 million unique US visitors in October, according to comScore Inc.

Weizman, the UC San Diego chemist, approaches each video he makes through the eyes of his students. For his inaugural project, he knew he wanted music in the background and a script that clearly explained every step of the experiment.

"I have a little picture in my mind of what I want to see," he said.

"That makes a huge difference."