The amount of water on Earth...

[terridean0515]

Has it been the same since time began or is it more or less?

 

How does the amount of water on the Earth change? Or does it?

 

If an apple tree gets cut down and all of the apples get made into apple juice and a person drinks all of the apple juice does the Earth gain water...did the apple increase the amount of water on Earth? Did the person's urine increase it? Did the person's body weight increase it?

 

Is there water we use that the Earth never gets back such as when we mix concrete or cookies for that matter?

 

Is this a question that cannot be answered?

 

I welcome emails at [email protected]

 

Thanks!

Terri

[terridean0515]

Hello. Wow! No responses. Is this question stupid? Is it something that cannot be answered? Please let me know why no one has replied. Thanks so much!!!!

Terri

[Tormod]

To be honest it's a bit difficult to know where to start, which might be why you haven't received any replies. Most of this stuff is easy to find out using Google, for example.

 

The water on Earth came here via comets over the hundreds of millions of years after the planet formed around 4.6 billion years ago. The amount of water on Earth is not constant as some of the hydrogen and oxygen will be bound into other things or get lost into space, but we also get more of these elements *from* space so that evens out the equation pretty much.

 

No matter how you use water on Earth it remains in the system, because human made things last extremely short compared to the time scales of geology. So eventually water you mix into concrete will escape and make it back into the ocean, for example. This process can take a long time, but all water on Earth is part of a huge cycle.

 

Water is perhaps the most important molecule for life on Earth, when we consider that absolutely all life as we know it consists mostly of water (our bodies are a prime example). Since we are a part of the ecosystem on Earth we do not "remove" water from the cycle. Every time you breathe or move, water vapor is lost from your body into the atmosphere. Urine is a waste product from metabolism and as such does not take away nor contribute, since all the ingredients are natural and come from outside your body in the first place.

 

So I guess the answer to your first question is, "no, in the beginning of the planet's history there was no water, but we have evidence of life in water that is about 3,6 billion years old, so we know that water has been around for a very long time".

 

The answer to your second question is "yes, but how it changes depends on what happens". If the temperature on Earth changes dramatically, the water will condense into thick clouds but it will likely remain on the planet. If for some reason our atmosphere should thin out, the water will boil off the surface and evaporate into space.

[Drip Curl Magic]

No matter how you use water on Earth it remains in the system, because human made things last extremely short compared to the time scales of geology. So eventually water you mix into concrete will escape and make it back into the ocean, for example. This process can take a long time, but all water on Earth is part of a huge cycle.

 

I've always been more worried about how much of the water we use gets recycled into fresh water. Obviously we've invented many things to keep the fresh water supply going(water purifiers and such)... but is that enough?

[cwes99_03]

Water gets recylced into fresh water all the time at the same rate. It is always getting recylced into freshwater by the water cycle. It falls back to the earth as freshwater (with a bit of dissolved gasses and what not).

This process is what keeps the sea level regular, the rivers flowing, the lakes from drying up. The only reason why cities need to reclaim water is that so many people are living in such a dense populated area, that the physical land they live on cannot support them without some aid.

Purifiers do not make "fresh" water. They simply remove contaminants. When we are talking about "fresh" water we are making a delineation between non-saline water and salt water, not between potable water and drinking water.

Normal urine is not so salinated that it isn't drinkable. If you were stuck on a raft in the ocean you would be able to survive longer (maybe an extra day) if you drank your own urine instead of attempting to drink sea water.

 

Matter cannot be created or destroyed (only converted into matter through fission or fusion process) unless it comes into contact with anti-matter (someone care to breach that here, or check out one of the other threads on anti-matter anihilation).