Incredibly grim video shows why you should always close the lid when you flush toilet

Scientists have recorded a grim video using lasers to show just how important it is to close the lid before you flush the toilet.

Researchers wanted to highlight the invisible-to-the-naked-eye droplets that are flung out of the toilet each times it’s flushed - and it makes for quite disturbing viewing, check it out:

In the clip, the water droplets show up a vivid green thanks to the lasers used and can be seen carrying quite a distance in the lab where it was filmed.

It’s always been known that when we flush the toilet a cloud of small droplets - known as an aerosol - is formed, which could spread germs.

However, this clip shows just how far those droplets can spread.

John Crimaldi, the study’s author and professor of engineering at the University of Colorado, told Business Insider the team’s ‘jaw dropped’ when they first saw the experiment as he had ‘no idea and no reason to believe’ they would carry as high and as wide as they did.

John Crimaldi

Writing in the study, which was published here, the researchers noted: “Our results demonstrate the surprisingly energetic and rapid growth of aerosol plumes from a commercial toilet and highlight the chaotic nature of the fluid kinematics that transport the particles.”

Crimaldi said his footage could change people’s perceptions of traditional toilets, and says he’s already started looking at them ‘suspiciously now’.

He told the publication: "You go to the bathroom, you flush the handle, the stuff disappears, you're like: 'boom, works great!'

"Then you look at the videos that we took and you're like: 'oh, maybe not so great!'

"I can tell you this has fundamentally changed my relationship with toilets. I look at them suspiciously now.

"I can sort of see in my mind's eye these aerosol clouds that are filling that whole room."

Luckily, there are ways you can protect yourself from potentially harmful germs.

John Crimaldi

Joshua Santarpia, a microbiologist at the University of Nebraska Medical Center, told Business Insider that to help minimise the spread of the droplets a toilet’s lid should be closed before flushing, if available.

Santarpia also suggests wearing a mask when in a public bathroom to avoid picking up any germs that may have been spread.

He explained: "Public bathrooms can be confined spaces with highly variable air change rates, so masking protects against human-to-human aerosol transmission, which is more likely in a small, poorly ventilated room, as well as contact with any potentially infectious aerosols from toilet flushing.”