ON STUDIES MOST SUITABLE FOR ELEMENTARY SCHOOLS. 521 



Simple experiments to show that air expands when heated, and that therefore 

 hot air is lighter than cold air; air currents due to difterences in temperature. 

 Necessity for and means of obtaining a supply of fresh air. 



Changes observed when typical foodstufis, e.g., bread, cheese, fat, and lean 

 meat, are strongly heated until ash remains; the presence of carbon, and the fact 

 that food is a combustible substance shown. 



Determine the amount of moisture in such food-substances as fat and lean 

 meat, bread, turnip, potato (raw and cooked). Mince the material (5 to 10 grams) 

 very finely and weigh it in a weighed evaporating basin ; dry it either by placing 

 the dish on a small saucepan containing boiling water or by placing it in a cool 

 oven until no further loss of weight occurs. 



Heat strongly some food-materials dried as above until only a grey ash 

 remains ; determine the percentage of ash in the original food. Show that the 

 value of a food-material depends upon the amount of dry solid nourishment 

 contained; that most beverages (milk excepted) contain little real nourishment. 

 Determine the amount of dry solid matter in a cup of milk, a cup of tea, a glass 

 of beer or whisky. 



Second Year. — Scheme B. 



Build up rectangular solids from cubes and deduce the rule for finding the 

 volume of a rectangular solid or space. The reasons for selecting the cube as the 

 unit of volume. 



The graduated cylinder, burette, and pipette; methods of use. Compare volumes 

 of a water-tight rectangular box obtained by (a) direct measurement, (6) by 

 measuring in the graduated vessels the water it will hold. 



Measurement of volumes of small solids by displacement of water in the 

 graduated vessels or of larger bodies, e.g., potato, ^^g, by ' overdow ' jar. 



The balance — adjustment and use ; weight of cubes of wood, potato, egg, &c., 

 to ^l-^ gram. 



Weight of volumes of water (30, 40, 50 c.c, &c.) measured from burette and 

 pipette, leading to the fact that a cubic centimetre of water weighs one gram. 

 Repeat experiments with hot water. 



Weight of known volumes of milk, diluted milk, skimmed milk, cream, beer, 

 spirits, tea, &c. Leave 100 c.c. of fresh milk to stand in graduated cylinder ; 

 measure number of c.c. of cream. Show that measurements of weight and volume 

 are used as an indication of quality or adulteration, and that the small amounts of 

 solid matter in tea, spirits, beer, as indicated by weights of unit volume, imply 

 small food-value. 



Simple experiments and illustrations to show reality of air. The three states 

 of matter — solids, liquids, and gases. Air, an invisible gas like coal-gas but 

 having no smell, is not so easily recognised. Refer to use of bellows and bicycle 

 pump. Pass air through water and collect it. 



Methods by which air may be extracted from a vessel ; experiments to show 

 that air has weight and that hot air is lighter than cold air and will rise above 

 it ; application to natural ventilation ; simple experiments to show that air exerts 

 a pressure on bodies. 



Draw air into the lungs through lime-water, and expel it again from the luDg.s 

 through lime-water. By breathing on a slate show that breathed air is highly 

 charged with water vapour. Expose dishes of lime, lime-water, and calcium 

 chloride to the air to show presence of moisture and something that turns lime- 

 water milky ; show that a candle will not burn in breathed air. Simple methods 

 of ventilating a room : doors, windows, chimneys. 



Burn a candle in ajar of air; it will burn if a continual stream of fresh air is 

 admitted ; if not, it goes out : measure the air absorbed during the burning ; what 

 fraction of the whole is it? The air left after the candle has burnt in it turns 

 lime-water milky, and will no longer support combustion. Repeat experiment 

 with a small lamp and phosphorus; examine and measure in each case the inactive 

 air left after the burning. 



Observe carefully the effects of heating fuel — coal, wood, peat — in a tube 



