Ontario Teachers' Manuals: Nature Study Part 29

_To the teacher._--The leaves of the red maple are longer than broad, and are not so smooth and shiny as the leaves of the sugar maple. There are numerous "saw teeth" on the margins of the lobes. The silver maple, with leaves having silver-white under surfaces, is another common species.

A lesson similar to that on leaf studies may be based on the fruits (keys) of the maples.

The oak, ash, elm, beech, or birch may be taken up in lessons similar to those outlined for the study of the maple.

CORRELATIONS

With literature and reading: By interpreting "The Maple", _The Ontario Readers, Third Book_, page 179;

With art: By sketching the tree and reproducing the autumn leaves in colour work.

WEED STUDIES

In every locality there are about a dozen weeds that are particularly troublesome, and the pupils of Form III should be taught to identify these and to understand the characteristics which make each weed persistent.

To produce these results it will be necessary to have exercises such as the following:

1. The teacher exhibits a weed to the pupils and directs their attention to a few of the outstanding features of the plant.

2. The pupils are required, as a field exercise, to observe where the weed is abundant; and whether in hay field, pasture, hoe crop, or in grain. The pupils will bring specimens to the cla.s.s.

3. Detailed study in the cla.s.s of specimens of the weed brought by the pupils to find offensive odours and p.r.i.c.kles, also the character of the leaves, flowers, seed pods, and seeds, including the means of dispersal; the underground parts, whether underground stem, tap-root, or fibrous root, and the value of the underground parts as a means of persistence.

4. The pupils make a collection of the weeds that have been studied.

(See Plant Collection, page 39, in General Method.)

5. The pupils make collections of the seeds of the weeds that have been studied.

OBSERVATION LESSON ON WEED SEEDS

The seed of a weed should always be exhibited and studied in a.s.sociation with a fresh or a mounted specimen of the weed.

Each pupil should use a hand lens in examining the seed.

The pupils examine the seed of each species and describe it according to the following scheme:

NAME OF SEED

_Colour:_ _Size:_ (in fractions of an inch) _Shape:_ _Details:_ _Occurrence:_

The results of the pupils' study of the ox-eye daisy would then appear in the following form:

SEED OF OX-EYE DAISY

_Colour:_ Black and greenish-white in stripes, _Size:_ One sixteenth of an inch, _Shape:_ Club-shaped, _Details_: Grooved lengthwise, yellow peg in large end, _Occurrence:_ A common impurity in gra.s.s seed.

GRa.s.sHOPPER

(Consult the Manual on _Suggestions for Teachers of Science_: Zoology, First year.)

The ease with which this insect may be obtained in August or September, together with its fairly large size, makes it a suitable specimen for insect study. It is also a typical insect, so that a careful study serves as a basis for a knowledge of the cla.s.s _insecta_.

FIELD EXERCISES

Problems to be a.s.signed for outdoor observation: Locomotion by flying, leaping, walking; protective coloration and habit of "lying low"; its behaviour when caught; in what kinds of fields it is most plentiful; in what kinds of weather it is most active; its position on the gra.s.s or grain when feeding; the nature and extent of the damage done by it.

Use a cla.s.s period for discussion of the above. Confirm, correct, or incite to more careful observation.

CLa.s.s-ROOM LESSON

(Studied as a typical insect)

~Observations.~--The three divisions of the body--head, thorax, abdomen; the segmental division of the two latter parts; the hard, protecting covering; the movements of the abdomen; the two large compound eyes and three small eyes; the feelers; the two pairs of mouth feelers; the cutting mandibles; the three pairs of legs (one pair for leaping) and two pairs of wings on the thorax; the breathing pores, the ears, ovipositors of the female.

The young gra.s.shoppers may be found in spring or early summer, and a few even in late summer, among the gra.s.s of old meadows and pastures. They are easily recognized because of their general resemblance to the adult and are in the stage of development called the _nymph_ phase. Note the hairy body and the absence of wings.

_To the teacher._--The moulting of the nymph is a very interesting process to observe and so is the laying of the eggs by the female in a burrow that she prepares in the soil. If females secured in July are kept in a jar having two inches of soil in the bottom, they will lay their eggs in the soil; the nests and eggs may then be taken up and examined.

In order that we may not destroy our friends and helpers, it is expedient to know what creatures help to hold pests in check.

The enemies of gra.s.shoppers are birds and insect parasites. Under the wings of gra.s.shoppers may frequently be found little red mites; these kill the gra.s.shoppers to which they are attached. The blister-beetles lay their eggs in the gra.s.shoppers' nests, and the larvae of the beetles feed upon and destroy the eggs.

The birds that are especially useful in destroying gra.s.shoppers are the meadow-lark, crow, bobolink, quail, gra.s.shopper sparrow.

The curious hairlike worms known to the school boys as "hair snakes"

because of the belief that they are parts of horse hairs turned into snakes, are worms that pa.s.s the early part of their life within the bodies of gra.s.shoppers and, when the insects die, the worms escape and are washed by rains into troughs and ponds where their movements attract attention.

Study the cricket and house-fly and compare the cricket with the gra.s.shopper.

APHIDES

In September obtain leaves of sweet-pea, apple, rose bush, maple, oak, turnip, etc., on which the insects are feeding; also provide specimens of woolly aphides on the bark of apple trees or stems of goldenrod or alder.

Observe the nature of the injury to the leaves and plants on which these insects feed.

Do the insects bite the leaves or suck the juices? Give evidence in support of your answer.

Sprinkle paris-green on the leaves; does this kill the insects? Why does it not? Spray the insects with a little oil, such as kerosene, or with water in which the stub of a cigar has been soaked; what is the effect?

Insects that suck juices from inside the leaf escape the poisoning from solutions in the leaf surfaces; such insects are killed by oils which enter the breathing pores and cause poisoning.

Search in the garden, orchard, and forest for plants attacked by aphides. Carefully observe the lady-birds that are frequently found where there are aphides. Lady-birds (also called lady-bugs), are small, spotted beetles, broad oval in form, of bright colours, red and black, or yellow and black, or black and white.

They are of great service to the farmer and gardener because their foods consists largely of plant-lice (aphides).