HETEROGENEOUS IDEAS 277

BIBLIOGRAPHYBLAIR, T. A. Weather Elements, Prentice-Hall, New York, 1942.HAYNES, B. C. Techniques of Observing the Weather, John Wiley & Sons, New

York, 1947.Smithsonian Meteorological Tables, Sixth Revised Edition, Washington, B.C.,

1951.Weather Bureau Publication Number 235�Psychrometric Tables for Obtaining

the Vapor Pressure, Relative Humidity, and Temperature of the Dew PointSuperintendent of Documents, Washington 25, D.C.

HETEROGENEOUS IDEAS FORINTERESTING DISCUSSION

JULIUS SUMNER MILLEREl Camino College^ El Camino College^ California

The principal functions in the classroom are, in my judgment, toawaken interest, arouse enthusiasm, teach concepts and guide rea-soning. These ambitions demand critical reading and analytic think-ing. There is, I fear, too much emphasis on memorization and re-gurgitation. It is true that a certain body of knowledge is a necessarypreamble to the acquisition of more but there is great need constantlyto provide exciting invitations to further learning. By exciting imita-tions I mean exercises removed from the humdrum of the textbook�exercises which invite and awaken curiosity and which stir studentsto debate and discussion. Constantly mindful of this I pose queriesthe answers to which are not generally found in textbooks. Here againI fear that we are too textbook bound and too classroom bound. Withthese things in mind then, my purpose in this note is to communicatesome exercises, some trivial, some not so, which my own studentshave found stimulating. Some can be used for brief classroom discus-sion, some can be used as laboratory exercises, extensions of simplercases. It is better, in general, to allow the students to harangue anddebate, even for weeks, than to provide the ^answers.^ It. is ex-tremely comforting to discover that this point of view, the stirring ofintellectual cziriosity, begets itself. Students are led by this device tolook at Nature more inquiringly, to look at things and see them, tolisten to things and hear them.

1. On many occasions, when I come to school in the morning, thegrass is wet with dew while the cement sidewalk adjacent to it is dry.Both were equally exposed to the water vapor in the air. Why is thegrass wet and the walk dry?

2. It is noted that trucks with trailer rigs which carry crushed stoneand gravel and sand have very long drawbars between the forwardtruck and the trailer, much longer than other truck and trailer out-fits have (e.g., gasoline tank trucks). Why is the drawbar so long?

278 SCHOOL SCIENCE AND MATHEMATICS

3. Consider the earth precisely 25,000 miles in circumference at theequator. A 6-foot man walks around it. How much farther does hishead travel than his feet?

4. Consider three massless, frictionless pulleys at the corners ofa right triangle in a vertical plane. Pass a smooth, just-fitting closedloop of chain or rope around the pulleys. What mil happen? Will mo-tion ensue?

5. A vertical-walled tank is filled to a depth h with water. Threeidentical holes are made in the side at distances A/4, h/2, 3A/4 fromthe top. Which issuing stream has the greatest horizontal range?

6. To find the focal length of a concave mirror, get 6-8 values ofp and q (object and image distance). This gives 12-16 values sincep and q are interchangeable. Why? Now plot p against q. Join corre-sponding values. All the straight lines interesect at /,/. Prove it.

7. To find the focal length of a convex lens arrange things asfollows: Set the object at one end of the optical bench, the screen atthe other. Their separation must be greater than 4/. Show this. Nowfind two positions of the lens for clear images on the screen. Then/= ((P�a^/^dy where a is the separation of the two lens positions andd the separation of object and screen. Prove this is so.

8. A drop of water lies between two glass plates, which are nowpressed together. A film of area A, thickness t, results. Find the forceto separate the plates.

RESEARCH PROJECTS APPROVED BY OFFICE OF EDUCATIONFourteen more educational research contracts totaling a half-million dollars

have been approved by the Office of Education, Department of Health, Educa-tion, and Welfare.The projects will be conducted by six colleges and universities, according to

Lawrence G. Derthick, Commissioner of Education. The Office of Education willproved $400,187, with the institutions adding $135,519.The contracting colleges and universities are Syracuse University, Syracuse,

N. Y.; George Peabody College for Teachers, Nashville, Tenn.; Ohio StateUniversity, Columbus; Southern State College, Magnolia, Ark.; Western Michi-gan Kalamazoo; and University of Alaska, College, Alaska.Mental retardation will be studied in a group of projects by Syracuse Uni-

versity, George Peabody College, and Ohio State University. Southern StateCollege will conduct research on retention of students in school; Western Michi-gan College, education problems of migrant children, and the University of Alas-ka, education for Alaskan Indians and Eskimos.More research proposals are under negotiation. An additional 42 proposals

were recommended for approval recently by the Office of Education^ researchadvisory committee.A total of 23 contracts, including the 14 announced today, has been signed

since the cooperative research program was launched a few months ago. TheOffice of Education’s contribution to the $845,706 total cost of these projectswill be $620,252. One to three years will be required for completion of the variousresearch projects.