Join JPL's new animated science ambassador on a whimsical and informative tutorial on how Earth's water cycle works and how NASA studies it.


Molecule Max Presents The Water Cycle

SONG: He's a water molecule, so give 'em a hand! He's really swell, He's Molecule Max!

Molecule Max: Time to learn about the water cycle! The water cycle is comprised of evaporation, condensation...

Off-screen: Giggles/laughs

Molecule Max: ...precipitation and runoff.... ...Okay, What's so funny...?

Emma: Uhhhh, What??? Molecule Max: Hey-what gives? I'm talkin' here.

Emma: You've got to be kidding.

Molecule Max: Listen, this is important scientific material.

Emma: Um, yeah. No, you really know your stuff, Mr... Talking-Water- Molecule-in-my-Office Man.

Molecule Max: I've been doin' this stuff for over 50 years. I think I know a little something about the water cycle-- Hey, what's all that? Hmmm... not bad. Working on a grant proposal, eh?

Emma: Actually, I'm working on an outreach presentation. It'll show our latest research and a new water cycle visualization.

Molecule Max: Well, I suppose a little updating never hurt anybody. Say, that looks cool. What's that?

Emma: Those are all the satellites that are observing parts of the water cycle. From space, we're finally getting a global perspective of the movement of water through the Earth system. And we're beginning to apply our new perspective to meeting our growing human needs for fresh water.

Molecule Max: Whoa! look at that! Those new satellites are a lot more advanced than they used to be.

EMMA: (laughs) Just a bit. Let me show you what we're learning from the data they gather. First, we're measuring atmospheric water vapor with high accuracy and spatial resolution. The data indicate that water vapor is increasing, which we think is related to an increase in the release of water from soil by evaporation and plant transpiration.

Molecule Max: Interesting, but what about condensation?

EMMA: Well, we can also observe clouds which tell us how efficiently water vapor is condensing at various altitudes in the atmosphere.

Molecule Max: Wow! The whole structure of clouds!

EMMA: Based on our cloud data, we've noticed an increased amount of clouds forming higher in the atmosphere.

Molecule Max: Is that affecting precipitation?

EMMA: Maybe, our measurements of global precipitation indicate that rainfall is increasing over land.

Molecule Max: So that must mean that rivers are fuller and delivering more fresh water back to the oceans?

EMMA: Yes, somewhat, despite the increasing amount of evapotranspiration and river alteration by humans.

Molecule Max: So the water cycle is really undergoing some significant changes! What's causing this?

EMMA: Well, for starters, our need for fresh water has really jumped since the 1950's. We've got nearly 3 times more people. And the typical family in the US now uses more than a hundred gallons of water per person-per day! So, given that only 3% of the water on earth is fresh water, and most of that is frozen in the polar ice caps, we humans are really changing the runoff part of the water cycle just to meet our needs. And here's the other big change! Look at these world temperature trends.

Molecule Max: Whoa-warmer temperatures must be causing more evaporation. Right?

EMMA: Exactly. Global warming trends seemingly have caused the whole cycling of water to speed up, with more evaporation, more water in the atmosphere, and more precipitation.

Molecule Max: With more and stronger storms and floods, I suppose?

EMMA: Yes, we are seeing them in some places, but not everywhere. So we need more information to make sense of the trends.

Molecule Max: Sounds like we need a better handle on the water cycle. You've shown me satellite data on water vapor, clouds, and precipitation. But are your satellites collecting data on evaporation and water runoff?

EMMA: Not yet because that's really hard to measure. But look at the future missions we'd like to do.

EMMA: First, we want to better understand how water flows on land surfaces. For this, we need two satellites-one to measure soil moisture, and another to look at surface water levels. Next, we want to measure how fast water evaporates from the ocean. We can do that by observing the ocean's salt levels. Last, we want to know how much frozen fresh water we've got. And for that, we need to measure snow and ice levels around the world.

EMMA: See, the thing is, we need to learn more so we can better manage the fresh water we do have. That's why our current missions-and all the terrific data we're getting, are so important- Molecule Max: You're right. There's so much new technology, and so many possibilities I can hardly believe it.

EMMA: I understand. Most of the research I do isn't so entertaining.

Molecule Max: Looks like I've got some work to do!

EMMA: Me too, or this is one outreach presentation no one's going to believe.
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