| It is him who | invented this machine. | Саме він винайшов цю машину. |
| It is the helmet that | saved my life. | Саме шолом врятував мені життя. |
| It is tomorrow that | I make a report. | Саме завтра я роблю доповідь. |
І. Decide which of these statements are true and which are false.
1. Diamonds are a form of sodium. 2. Diamond is the hardest mineral we know. 3. Friedrich Mohs was an Italian Physicist. 4. Quartz is harder than gypsum. 5. In diamonds, carbon atoms make a hexahedron unit.
ІІ. Answer the following questions.
1. What physical phenomena influence the creation of diamonds? 2. What property is the criterion for ordering minerals in the Mohs Scale? 3. How many minerals are there in the Mohs Scale? 4. What makes diamond molecules so strong?
Text 11. Are Cell-phones Harmful?
Active Vocabulary:
| cell phone | стільниковий телефон | frequency | частота |
| proximity | близькість | available | наявний |
| to cause | викликати | adverse | шкідливий |
| exposure | піддавання | to dissipate | розсіювати |
| tissue | тканина | vulnerable | уразливий |
| to alter | змінювати | ailment | нездужання |
| lead | свинець | fatigue | втома |
All cell phones emit some amount of electromagnetic radiation. Given the close proximity of the phone to the head, it is possible for the radiation to cause some sort of harm to the 118 million cell-phone users in the United States. What is being debated in the scientific and political arenas is just how much radiation is considered unsafe, and if there are any potential long-term effects of cell-phone radiation exposure.
There are two types of electromagnetic radiation:
· Ionizing radiation. This type of radiation contains enough electro-magnetic energy to strip atoms and molecules from the tissue and alter chemical reactions in the body. Gamma rays and X-rays are two forms of ionizing radiation. We know they cause damage, which is why we wear a lead vest when X-rays are taken of our bodies.
· Non-ionizing radiation. Non-ionizing radiation is typically safe. It causes some heating effect, but usually not enough to cause any type of long-term damage to tissue. Radio-frequency energy, visible light and microwave radiation are considered non-ionizing.
On its Web site, the FDA states that “the available scientific evidence does not demonstrate any adverse health effects associated with the use of mobile phones.” However, that doesn’t mean that the potential for harm doesn’t exist. Radiation can damage human tissue if it is exposed to high levels of RF radiation, according to the FCC. RF radiation has the ability to heat human tissue, much like the way microwave ovens heat food. Damage to tissue can be caused by exposure to RF radiation because the body is not equipped to dissipate excessive amounts of heat. The eyes are particularly vulnerable due to the lack of blood flow in that area.
The added concern with non-ionizing radiation, the type of radiation associated with cell phones, is that it could have long-term effects. Although it may not immediately cause damage to tissue, scientists are still unsure about whether prolonged exposure could create problems. This is an especially sensitive issue today, because more people are using cell phones than ever before. In 1994, there were 16 million cell-phone users in the United States alone. As of July 17, 2001, there were more than 118 million.
Here are a few illnesses and ailments that have potential links to cell-phone radiation: cancer, brain tumors, Alzheimer’s, Parkinson’s, fatigue, headaches.
If you are worried about the potential hazards of cell-phone radiation, here are a few ways to reduce your risk:
· Use a hands-free headset.
· Use a phone that places the antenna as far away from you as possible.
· Extend the antenna during use.
· Limit calls inside buildings.
· Limit use by children.