Table sugar is pure sucrose, C₁₂H₂₂0₁₁,made from the juice of sugar cane and sugar beets. The juice is purified and evaporated to a syrup which crystalizes as granulated sugar.
To grow your own centimeter-long sucrose crystals, called rock candy, stir 2 and 1/2 parts of sugar into one part of hot water and set the syrup aside in open dishes. Add a grain of sugar to each container to act as a seed crystal. In days or weeks you can collect the glittering rock candy crystals with a spoon and wash and dry them.
Western Canadians eat about equal amounts of beet and cane sugar for an average of 40 kg per person per year. These two sugars are identical in taste and appearance and only a chemist can tell them apart.
Plants breathe in carbon dioxide from the air and use sunlight and water to convert it to sugar by two different pathways of chemical steps. In seaweeds and grasses the pathway is called C-4 because the sugar is made from four-carbon molecules while in other plants the pathway is C-3 since they make sugar from three-carbon molecules.
About 99% of the carbon atoms in carbon dioxide weigh 12 times as much as a hydrogen atom and are called 12C atoms. The other 1 percent are 13C atoms because they are 13 times heavier than hydrogen.
As plants make sugar from carbon dioxide more of the heavy 13C atoms get left behind on the C-3 path than on the C-4 path. In the laboratory chemists break up sugar molecules in a mass spectrometer and sort the carbon atoms by weight. The sugar from beets (C-3) has only one half as many 13C atoms as sugar from cane (C-4).
This difference can be used to detect corn syrup in honey since corn is a C-A plant and bees visit C-3 plants such as clover. Mass spectrometers will also distinguish natural orange juice (C-3) from imitation orange juice made with cane sugar (C-4) or corn syrup (C-4).
Archaeologists use 13C/12C ratios from ancient bones to figure out the diet of prehistoric humans.
Chemists in Britain have recently replaced three of the eleven oxygen atoms of the sugar molecule with chlorine atoms. The product is called Sucralose and it is 650 times sweeter than sugar. It is being tested for safety as an artificial sweetner.

From Do-It-Yourself Chemistry
by Doug Hayward, University of British Columbia, 1988