This was written by Francis Crick, co-discoverer of DNA, about a year after they figured out it was a double-helix. In fact, in the article it’s still a bit of a hypothesis that DNA is a double-helix, they haven’t proved it yet.
The Structure of the Hereditary Material
An account of the investigations which have Led to the formulation of an understandable structure for DNA. The chemical reactions of this material within the nucleus govern the process of reproduction
by F. H. C. Crick
Viewed under a microscope, the process of mitosis, by which one cell divides and becomes two, is one of the most fascinating spectacles in the whole of biology. No one who watches the event unfold in speeded-up motion pictures can fail to be excited and awed. As a demonstration of the powers of dynamic organization possessed by living matter, the act of division is impressive enough, but even more stirring is the appearance of two identical sets of chromosomes where only one existed before. Here lies biology’s greatest challenge: How are these fundamental bodies duplicated? Unhappily the copying process is beyond the resolving power of microscopes, but much is being learned about it in other ways.
One approach is the study of the nature and behavior of whole living cells; another is the investigation of substances extracted from them. This article will discuss only the second approach, but both are indispensable if we are ever to solve the problem; indeed some of the most exciting results are being obtained by what might loosely be described as a combination of the two methods.
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If you are thinking of making this, keep in mind that 21 new elements have been discovered since it was printed. You can find out more at http://www.webelements.com/.
Building Blocks of Science
By HOWARD W. BLAKESLEE
Science Editor, The Associated Press
THE periodic table of the elements—the 96 metals, nonmetals and gases that form everything in the material universe— is the blueprint of the atomic future.
This table states a very simple fact: Everything material is made of three kinds of particles; namely, neutrons, protons and electrons. The difference between any two elements, iron and oxygen, for example, is in the number of particles.
On a map, specific places are always at specific points. The periodic table is like that. It tells facts about the elements that never change.
Although the table does not show where to look for uranium, it indicates the likely mineral formations. It shows that the kind of chain reaction that makes uranium bombs cannot be achieved without uranium’s aid. It also gives the limits of the uranium reaction and guarantees that it will not explode the earth.
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UPDATE: Somone on digg pointed out that if you look closely at the picture of the father and son filling a model Zeppelin on page two you can see that it says “Hindenburg” on the side.
HOME EXPERIMENTS WITH HYDROGEN
by VERNON TRACEY
HYDROGEN, the lightest of chemical elements forms a very interesting field of experiment for the home chemist. It can be produced easily in several ways for experimental purposes; one of the most common of which consists of the action of sulphuric acid on zinc.
A flask into which is dropped a few grams of zinc scraps is fitted with a rubber stopper, thistle-tube and delivery-tube as shown in the photo. The thistle-tube is fitted into the stopper so the end will be about 1/8″ from the bottom of the flask. The end of the delivery-tube is near the top of the flask. Dilute sulphuric acid is poured down the thistle-funnel and hydrogen is produced when it comes in contact with the zinc. The top of the thistle-funnel is covered with a piece of glass to prevent the hydrogen from escaping. The hydrogen flows out through the delivery-tube and is collected in a bottle over the pneumatic trough.
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