Exploring the Properties of Water - Fourth Grade

Water is pretty amazing. It not only comes in three forms: solid (ice), liquid (water), and gas (water vapor), but it covers most of our Earth--97 percent to be precise!

Water is also extremely important to ALL living things. In some organisms, up to 90% of their body weight comes from water. Up to 60% of the human body is water; the brain is composed of 70% water, while the lungs are nearly 90% water.

Insects called water striders can skate on water because of a unique property called SURFACE TENSION. Surface tension is caused by water molecules sticking together at the surface, creating a kind of "water skin."

And while most liquids contract (get smaller) when they get colder, water is different. Water contracts until it reaches 4 degrees Celsius and then it expands until it is solid. Solid water is less dense than liquid water because of this. If water was like other liquids, then there would be no such thing as an ice berg, the ice in your drink would sink to the bottom of the glass, and ponds would freeze from the bottom up!

Water is constantly being recycled through a process called "The Water Cycle."  Now sing this little ditty to the tune of "She'll Be Comin' 'Round the Mountain."

Water goes around in a cycle, yes it does!

Water goes around in a cycle, yet it does!

It goes up as EVAPORATION

Forms clouds as CONDENSATION

Then comes down as PRECIPITATION

Yes it does!