下の【語句】を参考にして和訳をお願いいたします。
Scientists often need to observe things that cannot be seen with the naked eye, either because they are too small or because they are concealed from view. There is a range of instruments and technologies that can be used to produce images of these small or hidden things.
The light microscope, first developed around 1600, uses lenses to produce a magnified image of small objects. In the late 1600s an Englishman, Robert Hooke, used a microscope to examine some cork and observed that it was made up of small units. He called these units “cells”. In 1939 the electron microscope was developed. It creates an image using electrons rather than light, allowing us to observe things that are far too small to be seen with a light microscope. “Scanning” electron microscopes, which produce three-dimensional images, were developed in the 1960s.
Other technologies, such as X-rays and ultrasound, produce images of the insides of objects. Like many scientific discoveries, the discovery of X-rays was an accident. In 1895 German physicist Wilhelm Roentgen, was experimenting with electrons in vacuum tubes. He noticed that this caused a fluorescent screen in another part of the laboratory to glow. When he put his hand between the tube and the screen, he saw the outlines of his bones projected onto the screen. He didn’t know what kind of radiation was causing this, so he used the term “X-rays”, because in science “X” represents an unknown. Atoms of heavier elements absorb X-rays whereas atoms of lighter elements do not. In the human body, calcium in the bones absorbs X-rays, but soft tissue such as muscle does not. So when X-rays pass through the body they can produce an image of the bones. Too much exposure to X-rays can cause radiation sickness, so X-ray technicians need to take special precautions. CAT（computerized axial tomography） scans use computers and X-rays to produce three-dimensional images. they examine the body “slice-by-slice” in a series of cross-sections, producing precise images. They are valuable in diagnosing diseased like cancer. Very high frequency sound waves are called “ultrasonic waves”. We can’t hear them, but bats and dolphins can. They send out ultrasonic signals and can tell from any echo whether something is ahead of them and how far away it is. Special spectacles using ultrasound have been made for blind people. Ultrasonic waves are used to detect tiny cracks in aircraft wings where microscopes can’t be used. And they are widely used in medicine. The waves are reflected from the boundaries between organs in the human body, producing pictures of the inside of the body. Ultrasonic waves are used to study embryos during pregnancy, because they are much safer than X-rays.
The ultimate study of small, hidden things is the study of the smallest particles, such as quarks, that make up all matter. This is done with huge machines called “particle accelerators”. Powerful magnets speed up particles to almost the speed of light. The high-speed particles collide with other particles, and the pieces left over from the collisions are studied with special detectors. The pieces can be as small as 10^（-15） meters※ and can’t be seen directly. It seems the smaller the thing being observed, the larger the machine needed.
【語句】
scanning electron microscope 「走査型電子顕微鏡」
Wilhelm Roentgen 「ウィルヘルム・レントゲン（1845-1923）」
radiation sickness 「放射線病」
CAT（computerized axial tomography）scan 「コンピュータ断層X線投影法」 CT scanともいう。
embryo 「胚（はい），胎児」
quark 「クオーク」
particle accelerator 「粒子加速器」
※10^（-15） meters 「10のマイナス15乗メートル」 1000兆分の1メートル
