# Why is mist coming from Niagra Falls?

I recently took a family trip to Niagra falls this summer and Got to go on the maid of the mist boat. When a relative asked if i could see the falls from my hotel i said that I could only see the mist rising from it and that got me thinking- why would there be mist rising from the falls?

A few minutes ago i did this expirament-

I took a bucket of water and placed it at the bottom of my backyard porch. Then, i climbed to the top of my porch and poured another bucket of water into the first. I observed no mist from either buckets.

Why then would mist be coming from Niagra Falls and not from my bucket, even on a smaller skale?

-PK

What gave you the idea that scaling down a physical system would give the same results? You may have noticed that Niagra Falls was somewhat higher than your porch. Objects free falling accellerate at approximately 32 feet per second, per second sometimes notes as 32’/second[sup]2[/sup]. Discounting air friction an object picks up another 32 feet per second for each second it falls.

Just because you didn’t see it with your eyes doesn’t mean it isn’t there.

The mist from a water fall is equivalent to shrapnel from a bomb blast. When the water riproars into the basin, the water thrown in all directions. There is enough energy to counter a lot of the inherent surface tension in the water, allowing for fine particulate water droplets to form and be carried along, boyantly, by the air in the form of mist.

Try using something that has a bit more kick (higher energy) a high pressure firehose into a bucket of water should do the trick. That oughta get you some mist in you midst.

While I have visited Niagra Falls a couple times, I am far more familiar with the falls out west like Multnomah in the Columbia River gorge.

Experiment to do at home. Turn on a faucet (one without an aerator is best) very slowly. Note that when the stream comes out it is fat, then thins, then turns to drops. The water speeds up as it leaves the faucet, this means the stream must narrow in order for the flow (speed times cross section) to remain constant. Once it gets small enough, it turns to drops.

Now, drops aren’t mist. But in a waterfall these drops can get moving quite fast, each following more or less the previous one. Now air pressure takes a role. It moves the drops around so that they don’t have the airstream advantage of following the previous one. Then they suddenly hit “hard air”. This splits them up into droplets and the droplets get smashed into mist.

You just weren’t holding the bucket high enough.

On narrow “horsetail” like waterfalls, this accounts for the majority of mist. But in the case of Niagra it probably is mainly due to hitting the bottom of the falls, as per previous posts. But I just wanted to mention this other effect …