To show the direction taken by the root and also by the shoot, take a glass jar with straight sides like a battery jar (a large fruit jar will do); line it inside with a layer of blotting-paper and then fill it with moist sawdust. Drop seeds of sunflower or squash down between the paper and the glass. The moisture from the blotting-paper will cause them to sprout, the shoot or stem always taking an upward direction and the root turning downward quite regardless of the position in which the seeds were placed.
10. Apply this study to seed planting: Plant seeds of wheat in four pots of soil, No. 1, half an inch deep; No. 2, two inches; No. 3, four inches; No. 4, six inches. Repeat this experiment, using buckwheat. What seeds are up first? What seeds last? Which are best after a week? After three or four weeks? From this experiment could you recommend a certain depth for the planting of wheat and buckwheat?
11. Does the kind of soil make any difference? To answer this have different pupils choose different soils, such as (1) coarse sand, (2) fine sand, (3) wet clay, (4) humus or leaf mould, (5) mixed soil or loam; and let each put in grains of wheat, two inches deep.
Allow five other pupils to plant seeds of buckwheat, under similar conditions. Treat all pots alike as to time of watering and quantity of water used on each and give them all equal light and heat. Note which come up first. Which are highest in one week, in two weeks, in four weeks?
12. This study may be continued in the garden by planting one plot each of corn, wheat, and buckwheat. Plots ten feet by twenty feet are large enough. Observe the rate of development in the plots. Which seems to mature most quickly? Which blossoms first? In what respect are the leaves of these plants alike or unlike? How do the stems differ?
Examine the blossoming and seed formation. When the grains are ripe, collect a hundred of the best looking and most compact heads of each grain and also a hundred of the smallest heads of each. Dry, shell, and store the two samples of each grain in separate bottles. These samples are for planting the following spring.
13. To show the need of moisture in germination: Fill two flower-pots or cans with dry sand; put seeds of sunflower in each, covering them an inch deep. Put water in one pot and none in the other. Examine both pots after two or three days.
14. To show that heat is needed for germination of seeds: Plant sunflower seeds in two pots as above; place one in a warm room and the other in a cold room or refrigerator; water both and observe result in three days.
15. To show that air is necessary for germination: Fill a pint sealer with hydrogen (the gas collected over water in the usual way, as shown in any Chemistry text-book). Put a few sunflower seeds in a small sponge or wrap them loosely in a piece of soft cloth. Keeping the mouth of the jar which has been inverted over water and filled with hydrogen, under the surface of the water, introduce the sponge containing the seeds, by putting it under the water and pushing it up into the jar. Seal the jar without letting the gas get out. Put some seeds in another jar in a wet sponge and leave the jar uncovered. Compare results after several days.
Here is a second experiment to prove this. Boil some water in a beaker in order to drive out all the air, put a few grains of rice in the water, and then add enough oil to make a thin covering on the water. This covering will prevent air from mixing with the water again. Put some rice in a second beaker without boiling or adding the oil. Leave the beakers side by side in a warm room for a week. The seeds will not germinate in the boiled water. It is not always easy to get rice that will germinate, but when it has been procured, the experiment is easy and very interesting. Any other seeds, such as those of pond lily and eel-grass, that germinate readily under water, will do as well as rice.