子供に勉強しろとせっついている「親」の方、自分で下記のアメリカの小学5年向けの理科の教科書を読んで理解できるかどうか、面白いと感じられるかどうかを試してみていただきたい。その後、さらに日本の小５の教科書、その中になければ中学生の教科書の記述と比べてみていただきたい。そうすれば子供が学校で何を感じているかが手に取るように分かるはずです。
Fifth Grade Science
物質
1.1 Atom
What could this hilly surface be? Do you have any idea? The answer is row upon row of atoms. To be specific, they are nickel atoms. The picture was created using a scanning tunneling microscope. No other microscope can make images of things as small as atoms. How small are atoms?
What Are Atoms?
Atoms are the building blocks of matter. Unlike blocks that we know, these building blocks are incredibly small. In fact, they are the smallest particles of an element. Atoms still have the same properties as the elements they make up. Elements are also pure substances. This means they are not mixed with anything else. Pure substances such as nickel, hydrogen, and helium make up all kinds of matter. All the atoms of a given element are identical. Atoms of different elements are not physically the same.
Think of something you might have made from LEGOs. You built some shape using the many different sized and shaped blocks. This is much like how atoms combine to become everything we know. If we took only one size and shape of block and put them together, we would make a pure substance. It would be an element. If you take apart anything that you have built, those individual parts are like the atoms. With those small parts, you build bigger things. Sometimes they are all the same type of block. Other times, they may be different kinds of blocks. We use these combinations of different blocks to make more complicated things.
Size of Atoms
Unlike LEGO bricks, atoms are extremely small. The radius of an atom is well under 1 nanometer. That's one-billionth of a meter. Such a number is hard to imagine. Consider this: trillions of atoms would fit inside the period at the end of this sentence. In other words, atoms are way too small to be seen with the naked eye.
Subatomic Particles
Although atoms are very tiny, they consist of even smaller particles. Atoms are made of protons, neutrons, and electrons:
Protons have a positive charge.
Electrons have a negative charge.
Neutrons are neutral in charge.
Parts of the Atom
Figure below represents a simple model of an atom. Models help scientists make sense of things. Perhaps they are either too big or too small. Maybe they are just too complicated to make sense of. This simple model helps scientists think about the atom. Is this how the atom really looks? Not exactly! Remember, a model helps us make sense of things. They may not be an exact copy of the object. You will learn about more complex models of atoms in the coming years, but this model is a good place to start.
This simple atomic model shows the particles inside the atom.
The Nucleus
At the center of an atom is the nucleus (plural, nuclei). The nucleus contains most of the atom’s mass. However, in size, it’s just a tiny part of the atom. The model in Figure above is not to scale. If an atom were the size of a football stadium, the nucleus would be only about the size of a pea.
The nucleus, in turn, consists of two types of particles, called protons and neutrons. These particles are tightly packed inside the nucleus. Constantly moving about the nucleus are other particles called electrons.
Protons
A proton is a particle inside the nucleus of an atom. It has a positive electric charge. All protons are identical. It is all about the number of protons in the atoms. The number of protons is what gives the atoms of different elements their unique properties. Atoms of each type of element have a characteristic number of protons. For example, each atom of carbon has six protons (see Figure below). No two elements have atoms with the same number of protons.
Neutrons
A neutron is a particle inside the nucleus of an atom. It has no electric charge. Atoms of an element often have the same number of neutrons as protons. For example, most carbon atoms have six neutrons as well as six protons. This is also shown in Figure below.
This model shows the particles that make up a carbon atom.
Electrons
An electron is a particle outside the nucleus of an atom. It has a negative electric charge. The charge of an electron is opposite but equal to the charge of a proton. Atoms have the same number of electrons as protons. As a result, the negative and positive charges "cancel out." This makes atoms electrically neutral. For example, a carbon atom has six electrons that "cancel out" its six protons.