アメリカのGrade5のテキストにはごくごく簡単なAtomic Structureが登場してくる。
その後にMiddle School（小６〜中２）のテキストには若干発展した内容でAtomic Structureが登場してくる。両方とも非常に分かり易い。
このMiddle Schoolの説明とほぼ同じ内容が日本の高校の教科書に載っているようだ。この事から推量すると日本のSTEM教育は致命的に遅れていると思われる。
一方、インターネット上で公開されているAtomic Structureについて日本語で書かれた数々の教材の説明は勉強の意欲を削ぐものばかりだ。非常にわかりにくい。
日米の教材を読んでみて、ようやく気づいた。日本で理科嫌いが多いのは教材の質が悪いからだ。
従って、日本語で書かれた教材を捨てて英語で書かれた教材を使えば学習意欲が飛躍的に高まるのである。おそらく理科嫌いはいなくなる。
理科嫌いの子供に勉強しろ、塾に行け、やれ予備校に行け、と言う前に親自身が下記に掲載したProton ,NeutronのMiddle School向けの解説を読み、日本の教材と読み比べて、日本語で書かれた教材が如何に劣っているかを体感してみるべきだ。中身はあくまで小６〜中２向けだ。
Identical Protons, Different Elements
All protons are identical.
For example, hydrogen protons are exactly the same as protons of helium and all other elements, or pure substances. However, atoms of different elements have different numbers of protons. In fact, atoms of any given element have a unique number of protons that is different from the numbers of protons of all other elements.
For example, a hydrogen atom has just one proton, whereas a helium atom has two protons.
The number of protons in an atom determines the electrical charge of the nucleus. The nucleus also contains neutrons, but they are neutral in charge. The one proton in a hydrogen nucleus, for example, gives it a charge of +1, and the two protons in a helium nucleus give it a charge of +2.
What Do Protons Contain?
Protons are made of fundamental particles called quarks and gluons.
As you can see in the Figure below, a proton contains three quarks (colored circles) and three streams of gluons (wavy black lines).
Two of the quarks are called up quarks (u), and the third quark is called a down quark (d).
The gluons carry the strong nuclear force between quarks, binding them together. This force is needed to overcome the electric force of repulsion between positive
What Is a Neutron?
A neutron is one of three main particles that make up the atom. The other two particles are the proton and electron. Atoms of all elements—except for most atoms of hydrogen—have neutrons in their nucleus. The nucleus is the small, dense region at the center of an atom where protons are also found. Atoms generally have about the same number of neutrons as protons. For example, all carbon atoms have six protons and most also have six neutrons. A model of a carbon atom is shown in the Figure below.
Properties of Neutrons
Unlike protons and electrons, which are electrically charged, neutrons have no charge.
In other words, they are electrically neutral.
That’s why the neutrons in the diagram above are labeled n0.
The zero stands for “zero charge.”
The mass of a neutron is slightly greater than the mass of a proton, which is 1 atomic mass unit (amu). (An atomic mass unit equals about 1.67 × 10-27 kilograms.) A neutron also has about the same diameter as a proton, or 1.7 × 10-17 meters.
Same Element, Different Numbers of Neutrons
All the atoms of a given element have the same number of protons and electrons.
The number of neutrons, however, may vary for atoms of the same element. For example, almost 99 percent of carbon atoms have six neutrons, but the rest have either seven or eight neutrons.
Atoms of an element that differ in their numbers of neutrons are called isotopes.
The nuclei of these isotopes of carbon are shown in the Figure below. The isotope called carbon-14 is used to find the ages of fossils.
Particles in Neutrons
Neutrons consist of fundamental particles known as quarks and gluons.
Each neutron contains three quarks, as shown in the diagram below. Two of the quarks are called down quarks (d) and the third quark is called an up quark (u). Gluons (represented by wavy yellow lines in the diagram) are fundamental particles that are given off or absorbed by quarks. They carry the strong nuclear force that holds together quarks in a neutron.
neutron
The Modern Periodic Table
A periodic table is still used today to organize the elements. You can see a simple version of the modern periodic table in the Figure below. The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass. Atomic number is the number of protons in an atom, and this number is unique for each element. The modern table has more elements than Mendeleev’s table because many elements have been discovered since Mendeleev’s time.
