My 8 year old grandson asked, “Could all the water on earth put out the sun”?

In fact, the sun is huge.  It is 864,400 miles (1,391,000 kilometers) across. This is about 109 times the diameter of Earth. The Sun weighs about 333,000 times as much as Earth. It is so large that about 1,300,000 planet Earths can fit inside of it.

So in answer to your question, if you were to take all the water off the surface of the Earth, where all the water is, you might then have a water balloon about the size of the North American continent. But all that water would do almost nothing, certainly not extinguish the sun, at most perhaps making it burn a bit faster from the added fuel, although the new burn speed would be negligible. Even the whole planet itself if it could be thrown onto the sun wouldn’t have any effect, excluding maybe a micro-hiccup in its daily process.  

But we’re told that one day the sun would go out, although not in our time, and certainly not through our efforts. The sun’s lifespan began roughly 4.6 billion years ago, and will continue for about another 4.5 – 5.5 billion years, when it will have depleted its supply of hydrogen, helium, and collapsed into a white dwarf.

Meanwhile back on earth we will rely more and more on the sun for our energy needs. Today while solar production provides less than one percent of the Earth’s energy needs solar (and wind power) are advancing on exponential curves. Every two years, for example, solar installation rates are doubling, and photovoltaic-module costs are falling by about 20 percent…. By 2030, solar power will be able to provide 100 percent of today’s energy needs, and by 2035, it will seem almost free — just as cell-phone calls are today.