Notes of Lessons: Physical Science, Class III

Notes of Lessons: Physical Science, Class III

[We have thought that it might be of use to our readers (in their own families) to publish from month to month during the current year, Notes of Lessons prepared by students of the House of Education for the pupils of the Practising School. We should like to say, however, that such a Lesson is never given as a tour de force, but is always an illustration or an expansion of some part of the children’s regular studies (in the Parents’ Review School), some passage in one or other of their school books.—Ed.]

Group: Science • Class III • Age: 13 and 14 • Time: 40 minutes

By W. T. Wilkinson
The Parents’ Review, 1903, pp. 147-149

Glacial Action

Objects

I. To help the pupilstotrace cause from effect, and so develop their powers of reasoning.

II. To cultivate a taste for independent mental activity.

III. To give the pupils a further interest in their own district.

IV. To help the pupils to recognisefrom the evidences left behind that there were once great glaciers in England.

Lesson

Step I.—Make sure that the pupils know what a glacier is and how it is formed. Let them tell where glaciers can now be seen, i.e., in Switzerland, Norway, etc.

Step II.—Glaciated Rocks. Show the pupils a piece of glaciated rock found in the Lake district, and ask if they know what has made the striations upon it, and why the side with the striations is polished. Ask them for local examples of similar rocks where the striations are well marked, as on the rock in Ambleside Churchyard.

Step III.—Put these sketches on the board:—Ground before a glacier has passed over it, and ground after being smoothed by the action of a glacier; and let the pupils think which way the glacier has passed, namely, from left to right, smoothing down the slopes on the side facing the glacier, and leaving the sheltered side almost unaffected, with débris in the hollow.

Compare the appearance of English glaciated rocks with those of Switzerland by showing a picture of the Grimsel.

Step IV.—Moraines. Show the pupils pictures of moraines that have been formed, as in Borrowdale; and of moraines now being formed, as on the “mer de glace,” in Switzerland.

Draw from the pupils how those moraines have been formed, i.e., by stones and rubbish falling on to the glacier, and either being banked up or thrown off at the sides, as in lateral moraines; or left where the glacier melts into streams,as in terminal moraines, or being carried along by the streams and spread over the land, as inmorainicmounds or drift. Tell the pupils that this drift is a stiff clayey soil with boulders of rock in it, and is found as far south as the Thames Valley.

Step V.—Show the pupils the map of the Lake district, and, if they do not know, show them wheresome good examples of moraines and morainicmounds can be seen, as in the Grisedale. St.John’s, Greenup and numerous other valleys, and in the Honister Pass.

Let the pupils find out from the lie of the moraines the direction and limits of the passage of some of the Lake district glaciers.

Step VI.—Erratics. Show the pupils some pictures of Erratics, and tell them what kind of stone they are, viz., at Wolverhampton is a large block of Scotch granite and blocks of andesite from the Lake district; at Birmingham there are large blocks of stone from the Arenig mountains in North Wales; at Flamborough Head there are blocks of Shap granite; and in Norfolk and Lincoln are blocks of stone only found in Scandinavia.

Get the pupils to say how these blocks got to their present destinations, so far from the parent rocks, and say why they could not have come by water or by icebergs—because they are not rounded or water worn, nor are they scattered indiscriminately, but follow a certain definite plan, i.e., those found in Lancashire and Cheshire are always to the southwest of the place of origin.

Step VII.—Mention the names of some Arctic animals, e.g., musk sheep, Arctic fox; and trees, as the Arctic willow and dwarf birch, the remains of which are found in England in the drift and river-glacial deposits.

Step VIII.—From these evidences let the pupils draw the conclusion that this country was once united to the Continent, and that the part of England north of the Thames was once covered with ice,as isGreenland in the present day.

Let the pupils show, on a map, the directions of the Scotch, Lake district and Scandinavian glaciers, and make a rough sketch of their directions on the board.

Step IX.—From their knowledge of the position of glaciated rocks and moraines, draw from the pupils the fact that the glacial formation lies next to the recent formation. Tell them that these two formations belong to what is called the Quaternary system, the most recent system of the four great series into which the formations of the earth are divided. Tell them that the Glacial Period is supposed to have begun about 200,000 years ago, and lasted about 150,000 years.

Step X.—Recapitulation.