Sugar dissolves in water and can chemically bond in water. It can change the way water performs. Whether you want to raise the boiling point of water or keep your vase of roses alive longer, it's good to know just how sugar affects water.
Raises Boiling Point
Sugar, like salt, and in fact like all non-volatile solvents, affects the boiling and freezing point of water. Because sugar has a lower vapor pressure than water, when it is mixed with water, it lowers the overall vapor pressure of the mixture. Vapor pressure is what determines how much heat energy must be added or subtracted for a substance to change its state--the lower the vapor pressure, the more energy is required. Next time you'd like to cook at a higher temperature, try throwing a bit of sugar into your pot instead of salt.
Makes Syrup
You can transform water into a syrup with the addition of sugar and heat. As you heat the sugar-water, water evaporates. Thus, the ratio of sugar to water is higher, and the moisture has a new, higher boiling point. The mixture can continue to grow hotter and hotter, and as more and more water boils off, the mixture grows thicker.
The highest temperature reached will indicate how thick your sugar syrup will be when it cools--you may even end up with candy. But the syrup forms, even if you're not heating it at much above water's boiling point, 212 degrees Fahrenheit, because the heat allows double bonds to form between the sugar and the water.
Feeds Cut Flowers
Adding sugar to water makes it more nutritious for certain cut flowers, especially roses and snapdragons. Although plants usually photosynthesize their own sugar from sunlight, cut flowers, which get little light in dim dining rooms and often suffer from leaves removed for aesthetic reasons, could use the sugar boost.
Don't go feeding sugar water to your outdoor plants, though, as they won't be able to absorb anything from the soil but nutrients and water. Cut flowers have their xylem--their water ducts--cut and exposed to the water in their vase. In the case of cut flowers, the sugar has no roots to contend with and may enter the xylem directly, unlike with plants still in the ground.
Tags: boiling point, sugar water, vapor pressure, lower vapor, lower vapor pressure, point water
