exerts a stronger pull on the electrons (small dots) it shares with the hydrogen atoms, the water molecule is electrically unsymmetrical The separation of positive and negative centers of charge leads to the formation of weak bonds between oppositely charged centers on different molecules These weak bonds between molecules, shown here by dashed lines, are called hydrogen bonds Water Is Good at Dissolving other Substances Water forms hydrogen bonds not only with itself, but with other substances that have at least some electrical polarity, some unevenness in the distribution of positive and negative electrical charges Of the other major food molecules, which are much larger and more complex than water, both carbohydrates and proteins have polar regions Water molecules are attracted to these regions and cluster around them When they do this, they effectively surround the larger molecules and separate them from each other If they do this more or less completely, so that each molecule is mostly surrounded by a cloud of water molecules, then that substance has dissolved in the water Water and Heat: From Ice to Steam The hydrogen bonds among its molecules have a strong effect on how water absorbs and transmits heat At low temperatures, water exists as solid ice, its molecules immobilized in organized crystals As it warms up, it first melts to become liquid water; and then the liquid water is vaporized to form steam Each phase is affected by hydrogen bonding Ice Damages Cells Normally, the solid phase of a given substance is denser than the liquid phase As the molecules’ attraction for each other becomes stronger than their movements, the molecules settle into a compact ... water molecules, then that substance has dissolved in the water Water and Heat: From Ice to Steam The hydrogen bonds among its molecules have a strong effect on how water absorbs and transmits heat At low temperatures, water...effectively surround the larger molecules and separate them from each other If they do this more or less completely, so that each molecule is mostly surrounded by a cloud of water molecules, then that substance has... melts to become liquid water; and then the liquid water is vaporized to form steam Each phase is affected by hydrogen bonding Ice Damages Cells Normally, the solid phase of a given substance is denser than the liquid