2007-03-21 13:19:14 · 4 answers · asked by Kayla 1 in Science & Mathematics ➔ Biology
"Water sticks to itself (cohesion) because it is polar, meaning one end of the molecule has slight negative charge while the other has a slight positive charge. In water, this happens because the oxygen atom is more electronegative than the hydrogen atoms—that is, it has a stronger "pulling power" on the molecule's electrons, drawing them closer (along with their negative charge) and making the area around the oxygen atom more negative than the area around both of the hydrogen atoms."
Cohesion allows water to stick to itself up the tree.
2007-03-21 13:24:03 · answer #1 · answered by Sean Walker 3 · 1⤊ 0⤋
Water is a polar molecule that has significant hydrogen bonding power. The two forces that allows water to move up the stems are adhesion and cohesion. Cohesion is what holds the water together and tries to minimize the surface area, which is what causes the spherical-shape drops that we see. Adhesion is the interaction with the polar molecules of the stems. The hydrogen bonds try to maximize the interaction with polar surface of the stems pulls the edges of the water slightly higher; this is the phenomenon that results in the meniscus when water is placed in a graduated cylinder. The combination of the two forces, adhesion pulling the sides up the stem and the cohesion trying to reduce the size of the meniscus, is what forces the water up in the form of capillary action.
2007-03-21 20:34:38 · answer #2 · answered by homertorpedo 3 · 0⤊ 0⤋
water is a polar molecule. since oxygen is very electronegative, it pulls more shared electrons closer to itself, leaving the oxygen end of water with a slight negative charge while the hydrogen ends have a slight positive charge. when water molecules are together, they arrange themselves so that their positive H ends are stuck to negative O ends in a special form of dipole-dipole interaction called hydrogen bonding. hydrogen bonds are not extremely strong, but many hydrogen bonds together requires a lot of energy to break, therefore water is attracted to itself. in trees and other tubes, water sticks together. When the water molecules at the top leaves evaporate, it pulls the rest of the water molecules upwards, sort of like pulling a string up, for instance. This phenomenon is called cohesion-tension theory.
2007-03-21 20:29:47 · answer #3 · answered by Motoko 3 · 0⤊ 0⤋
Dude, it's totally polar. I think that has somethin' to do with it.
2007-03-21 20:24:38 · answer #4 · answered by Anonymous · 1⤊ 0⤋