What conditions are necessary to fling water in the air such that it all turns to vapor?

During the cleanup of an outdoor party, it’s common to empty glasses by flinging the liquid into the air, which then lands on the ground. This got me wondering if it’s possible for there to be conditions such that all the water stays in the air as vapor rather than land on the ground. If so, what is the maximum amount of water that could be thrown by a human where 100% would end up as vapor?

I’m sure there are a lot of factors that will affect this, so assume any reasonable conditions that would be appropriate, such as temperature (of the air and water), humidity, or anything else that may be relevant. And no, the answer is not that the party is held on an active volcano where the lava would instantly vaporize the water.

I’m assuming that the dryer the air, the better it would be. And the hotter the water in the container, the better it would be. But I’m not sure if hot or cold air would be better. Would cold, dense, dry air suck more of the water in? Or would the density prevent the water from turning to vapor? Or would hot, expanded air allow more of the water to turn to vapor more easily?

Boiling water into cold, dry air. Not the kind you would be having a picnic in. Think Alaska in January. You can youtube videos of it.

I’ve seen those, and they’re extraordinarily beautiful, but doesn’t the water turn to ice crystals, which then fall to the ground like snow? And I wonder if they do it in the cold air for that crystal effect rather than because the cold air holds more water vapor.

Perhaps with the hypersonic jet from a water cutter, if you aim it up into the air?

I see no reason why hotter would not be better, for both the water and the air.

As noted, that water is freezing, not evaporating (turning to vapor). I think you’d be best off using as little water as you could*, have it as hot as possible (boiling) and doing on a hot, dry day.
If you wanted to use external devices to help, pump the hot water into a pressure sprayer or a garden hose with nozzle that has a mist setting.
*If you fling a half a cup of water into the air, it’s more likely to separate and have more surface area and have a chance at evaporating. The bigger the amount of water, the more likely it is to just come right back down in, more or less, one big blob.

That’d be awesome! I need to get one of those! But I’m more wondering if it can be done without any fancy equipment. I’d be a fun party trick. If I happened to find myself in Death Valley, a cold mountain peak, or wherever the conditions are perfect, it’d be a cool trick to throw some water into the air and have it all evaporate.

Would it work better in a vacuum?

You’d have to really work on the picnic part.

There are “misters” which can spray a significant amount of water into the air, which will completely evaporate if the conditions (hot and dry) are right.
They are common out here.

The key is to have a small droplet size and very hot and dry air.

It’s one of the standard cold-weather games here in Minnesota, when it’s -25F or below outside. Throw a pan of water in the air and none will hit the ground. Leave a banana outside overnight and you can drive nails with it. Leave an orange outside and it’ll shatter like glass when you throw it at the ground. And let’s not talk about cars.

You’d probably be best off throwing it from the top of some sheer precipice, so it’d have a long way to fall before hitting the ground.

Ultrasonic vaporizers turn water directly into vapor. We can use that principle to meet the requirements of this problem.

Coaxially mount a water jet and a tight-beam ultrasonic projector. Turn them both on and adjust their “volumes” until the water is perfectly vaporized. Also, can be tuned into a weapon for Aquaman.

Obligatory xkcd comic.

Cold air can hold a smaller amount of vapor (measured as concentration) than warmer air.

Nothing you can reasonably do will accomplish the OPs scenario.

Water has a very high latent heat of evaporation. There is no way that a glass of water falling from a height of few feet will encounter enough air to evaporate complete. The air simply could not provide the heat.

As a perspective, consider the large cooling towers in a nuclear or thermal power plant. The cooling towers are doing just what you ask in the OP’s question.

What’s happening is that it immediately vaporizes and then condenses into the cloud formation. The dry air then causes a re-evaporation and the cloud disappears (providing the relative humidity is below about 30% or so.) Of course, it depends on the temperature. In the teens, it vaporizes, once you get below zero, instead of evaporating the second time, you will start to see crystalization and you get the snow effect. In the teens though, it just turns into a cloud that evaporates away.

I don’t think there is any scenario in nature, in a human-survivable environment, that fits the description required. It would probably require such high temperatures, or vacuum, or something that it would either be 1) dangerous as to be impractical and/or 2) could only be replicated in some indoors or lab facility.

In the hot, dry US Southwest, this happen quite often on a grand scale. Thunderstorm will come over the mountains and drop their water on the desert below, but it will all evaporate before it hits the ground.

Now, these thunderstorms are 10,000 feet, or higher, so the water has a long way to fall. Maybe if you got a cup of water and were able to throw it really, really high…


It’s tolerably common in lots of areas with a dry climate.

No, they don’t. They turn water into tiny droplets, which are then ejected from the machine’s port into the room (you can see this fog coming out of the machine). The droplets then rely on the heat of the room to turn them into vapor.

If you want liquid water to evaporate, that phase transition takes a lot of energy. This is why evaporative cooling (e.g. sweating and “swamp coolers”) works so darn well. Here are things that will work in your favor:

[ul][li]You can give things a head start by pre-heating your vessel of liquid water to somewhere close to the boiling point. [/li]
[li]You can go even further by working in a very hot, dry environment (think Death Valley, Phoenix, or Las Vegas). [/li]
[li]Atomize your liquid water as finely as you can manage. Liquid water evaporates at free surfaces; transforming your cup/pot of water into a collection of tiny droplets maximizes the surface area. Not only that, but smaller droplets have a lower terminal velocity, which means they’ll take longer to fall back to earth, providing more “hang time” during which to evaporate.[/li]
[li]Disperse your liquid water droplets into as large a volume of atmosphere as you can manage. This gives it access to a lot of atmospheric heat, giving the best chance of vaporizing all of that water. If you don’t do this, a little bit of your water vapor will saturate a small volume of air to 100% relative humidity, preventing the rest of the liquid water from evaporating.[/ul][/li]
According to this psychrometic chart (PDF), at 70F and 100% relative humidity, the air contains 110 grains of water per pound of air. IOW, for every gram of water you want to evaporate, you’ll need about 64 grams of air Got an 8-ounce (250-gram) cup of water? You’ll need to disperse that cup of water into 16,000 grams of air (this assumes the air was at 0% humidity in the first place). That’s about 13 cubic meters of air - a box 2.4 meters on a side. If you can atomize your water into adequately small droplets (as an ultrasonic humidifier does), then this will work.

The problem is that for a human flinging water by hand out of a little red Solo cup, the droplet size is going to be huge. Like raindrops. I can’t imagine any quantity of water that could be human-tossed that would evaporate completely before hitting the ground.

I accept your nitpick, because “directly” is subjective. But it’s like saying a chainsaw cannot directly fell a tree–all it does is remove the tree’s support and then relies on local gravitation to pull it down.