Everyday food substances can be examined through a microscope, the microscope unveils the details of its structures, and each one will be a new surprise. Try examining pepper, coffee, and a dab of mayonnaise, cereal grains, tealeaves, powdered spices, onionskin, lettuce leaf, and egg white.
Potato is a starchy food. It is possible to see exactly where the starch of the potato when viewed under a microscope. Cut the uncooked potato in half and, with a knife blade, scrape off some of the pulp.
Mount a bit of pulp over a microscope glass slide and examine the cells that make up the tissue of the potato. Add a drop of a weak solution of iodine in water to the specimen in the microscope glass slide to make the grains of the starch more visible. Notice that the areas where the starch is concentrated have turned a bluish black color.
Plants manufacture substances other than starch. Nuts, for instance, are particularly rich in fats or oils. Oil-rich tissue is demonstrated by shaving a few thin slivers from a Brazil nut, pecan, or walnut. Place the shavings on the microscope glass slide and add a drop or two of Sudan III.
In about five minutes, this stain dissolves in the fat cells of the nut coloring them reddish-orange. The observer can see the stain coloring the fat cells as it penetrates the tissues of the nut by looking underneath a microscope.
Examination of a stalk of celery reveals some interesting facts about how plants draw water up from the soil and into the branches and leaves. Make a clean cut across the bottom of a celery stalk, and dip the cut end into a beaker of ink.
Soak the stalk in the ink for twenty-four hours. Remove the celery and slice off a very thin section of the stalk. Place it on a microscope glass slide. Examine the cross section under the microscope. Notice that that the dark spots are filled with ink that is being transported to the upper parts of the plant.
Examine it carefully and you will discover that the dark spots are really the cross section of a bundle of about a dozen tubes. Through these tubes, plant can transport water from the earth.
