What uses do spiders make of their webs? (Trapping prey, supporting egg cases, protection, and means of moving, as in the case of cobweb spiders.)
Drop a fly upon a spider"s web and observe the action of the spider.
Search under the webs of spiders in attics and sheds and learn, from the skeletons found there, what the spider feeds upon. It will be found that flies, beetles, and other spiders are killed by this monster.
Watch a spider spinning its web and find out what parts of the body are used in this work. It will be seen that the threads are produced from little tubes at the rear end of the animal and are placed and fastened by means of the feet.
Examine, by the aid of a hand lens, the feet and head of the spider.
Note the "brushes and combs" on the former. Note, on the latter, the four, six, or eight eyes (the number and arrangement vary), and the short poison claws at the front of the head. How are the poison claws adapted for seizing and piercing? Note the sharp hooks at the lower ends.
BIRD STUDIES
Continue the lessons in bird identification and in bird types, using the methods outlined for these studies in Form III. (See pp. 217-24.)
CHAPTER XIII
FORM IV
WINTER
FOREST TREES
EVERGREENS
Several species of evergreens have already been studied. These should be reviewed, and representatives of other species examined. Mid-winter is most suitable for the study of evergreens. The following points should be considered:
1. Description leading to identification
2. Nature of soil and water conditions
3. Common uses of each species of evergreen
4. Collection of wood specimens and cones.
WOOD SPECIMENS
Specimens should be uniform in size and should show bark on one side and heart wood as well as the outside, or sap wood. They should be about six inches long, two inches wide on the side having the bark, and should gradually come to an edge toward the pith, or centre. When seasoned, one side and one edge should be polished and then oiled or varnished.
Specimens of the wood of the deciduous trees may also be prepared during the winter.
FRUITS
During the winter months, some time should be devoted to reading and discussing articles on general farming and fruit growing. Such articles may be taken from books, magazines, or newspapers, and may be supplied partly by the teacher and partly by the pupils. These articles will be appreciated by the pupils all the more because of their studies of fruit trees during the season. Such topics as the following may be discussed:
1. Best kind of apples, plums, bush fruits, and strawberries. Reports from the Dominion and Provincial Departments of Agriculture.
2. Method of raising fruit trees--from seed, grafting, and budding.
3. Demonstrations in pruning. This may be done in early spring by taking a cla.s.s to a neighbouring orchard.
4. Methods of planting and cultivation.
5. Packing and storing.
6. Spraying. Much information is to be found in Horticultural Journals and papers, and in Bulletins to be obtained from the Secretary of Agriculture for Ontario.
Ill.u.s.trated articles on gardening and fruit growing should be collected for school use. Views of fine gardens, parks, and home grounds will be of interest to the pupils. Simple artistic methods of ornamental planting with trees, shrubs, vines, and herbaceous perennials can now be introduced, and some scheme for improving the school grounds outlined.
Catalogues should be obtained soon after New Year"s and, after examining their merits, the best varieties of seed and fruit for the district should be selected. Horticultural societies, as well as Dominion and Provincial Departments of Agriculture, commonly give selected lists with descriptions of the different varieties.
WEEDS AND WEED SEEDS
The training in the observation and identification of weeds and weed seeds, which was begun in Form III, should be continued in Form IV. For method see Form III.
PHYSICAL SCIENCE PHASE OF NATURE STUDY
WATER PRESSURE
1. Grasp an empty tin can by the top and push it down into a pail of water. Note the tendency of the can to rise. The water presses upward.
Its downward pressure is evident.
2. Tie a large stone to a string, hold it at arm"s length, shut the eyes, and lower the stone into water. _Note_ the decrease in weight.
This is also due to upward pressure, which we call buoyancy. The actual decrease may be found by means of a spring balance.
3. Try Experiment 2, using a piece of iron the same weight as the stone.
Is the decrease in weight as evident? Ships made wholly of iron will sink. Explain.
4. Put an egg into water; it slowly sinks. Add salt to the water; the egg floats.
EXERCISES
1. Will the human body sink in water? In which is there less danger of drowning, lake or sea water?
2. When in bathing, immerse nearly the whole body, then take a full inspiration. Note the rise of the body.
3. Why does ice float? (See expansion of water by freezing.)
4. Balloons are bags filled with some light gas, generally hydrogen or hot air. They are pushed up by the buoyancy of the air. The rise of heated air or water (see Convection) is really due to the same force.
Clouds, feathers, and thistledown are kept in the air more by the action of winds and small air currents than by buoyancy.
STUDY OF AIR