Water, water, everywhere!

When it comes to space exploration, nothing makes the news quite like the possibility of finding extra-terrestrial water. Just over a month ago,  a research team from Japan used the Subaru Telescope to observe the water-rich atmosphere of Gliese 1214 b, a planet 40 light years from Earth.

Why are we always searching for water in space? What does discovering water have to do with the possibility of discovering extra-terrestrial life? 

To begin answering these questions, we explored some of water's interesting properties through the following investigations:

Water's molecular structure: We made models of water molecules, noting how oxygen and the 2 hydrogens share electrons.

Water sticks to other water molecules and other stuff too: We observed the U-shaped water line in a graduated cylinder and the dome shaped water line, as you fill a cup just beyond the brim.

Water is strangely denser than its solid form, ice. 

Water's a great solvent: We saw how water dissolves marker ink and carries along its components through filter paper.

Finally we discussed why these properties are so important for life as we know it.

Biology: "Newly discovered planet may have water on its surface" ....so what?

Just about a year ago a team of astronomers announced the discovery of an extrasolar planet, called Gliese 581g*. What's neat about Gliese 581g is that it may have liquid water on its surface.  When scientists search for water in space, they're looking for just one thing: life.

What makes water so special, and why do we think it's essential for life? These were some of the questions we set out to explore on day 1 of Biology. We started off by observing water's amazing ability to dissolve other substances. The kids prepared strips of filter paper, each one with a different marker color. After placing them in a bowl of water, we watched as the water traveled up the papers and dissolved the inks, revealing surprising bands of different colors.

We talked a bit about the chemical structure of water and how this structure allows water to dissolve substances easily and in doing so helps along the important chemical reactions necessary to sustain life.

*http://en.wikipedia.org/wiki/Gliese_Catalogue_of_Nearby_Stars

Biology: More on water

This week we continued our discussion on why water is special and necessary for life. We compared how tap water, sea water, and air respond to changes in temperature. The obvious answer is: put things on the stove they get hot, put things on ice, they get cold. What's less obvious is that not everything heats and cools at the same rate, and not everything freezes and boils at the same temperature.

In the ice bath, the test tube with water and sea water cooled more slowly than the air. On the stove our results were somewhat less consistent. What we know from our more experienced collegues is that water is both relatively hard to cool and hard to heat,remaining a liquid over a wide range of temperatures. And as we discussed last week, liquid water is what it takes for life as we know to exist.