April. 10171 Scientific Drawing in Biology 207 



SCIENTIFIC DRAWING FOR TEACHING PURPOSES. 



Blackboard Drawing. 



Blackboard drawing is most important. It is rapid and is 

 simultaneous with or follows the explanation. This combination 

 affects both sight and hearing and thereby makes mental efforts 

 easier and more successful. 



If you have complicated drawings to make, they should be 

 done before the lecture. A thing which takes some time to 

 make and which might be used more than once should be made 

 as a chart which can be left hanging for reference. The simpler 

 drawing constructed as the idea is being presented has great 

 advantages as the student is able to transcribe it into his notes. 



Do not shade a black board drawing since the natural order 

 of things is reversed and the dark boundary is being reproduced 

 as white. Make your outlines heavy for easy vision. 



For differentiation of structures use such colored chalks as 

 will easily show at the back of the room. It is artistically ille- 

 gitimate, but you can give an impression of relief by using 

 thicker lines where the shadows should be. This is useful, for 

 example, in drawing cleavage. 



A blackboard drawing is for the moment only and need 

 possess little artistic merit. I have seen an elaborate blackboard 

 drawing hamper teaching because it was made so well that no 

 one had the heart to erase it. 



Charts. 



For making charts one should have a drawing table at least 

 52 inches wide whose four sides are squared so that a T square 

 43^ feet long can be used on it. If you use the Metric system of 

 measurement enlargements can be made more easily. 



The best chart material is canvas backed bristol board. 

 This can be purchased in various sizes. I have gotten two sizes. 

 Rectangles, 16 inches by 24 inches, convenient for small dia- 

 grams and continuous rolled material a yard wide from which 

 charts of any desired length can be made. Heavy Manila paper 

 will do but is likely to tear along the edges after years of putting 

 up and taking down. The smaller charts are easily hung 

 using thumb tacks while the larger ones rolled on wood need 

 some sort of hooks. 



