Washington (CNN) -- The U.S. Food and Drug Administration announced Wednesday that laboratory tests on popular smoking devices known as electronic cigarettes have found they contain carcinogens and other toxic chemicals dangerous to humans. E-cigarettes are battery-operated and contain cartridges filled with nicotine and other chemicals. Known as "e-cigarettes," the devices are battery-operated and contain cartridges filled with nicotine and other chemicals, spiced with flavors such as chocolate, cola or bubble gum. While manufacturers tout e-cigarettes as a "healthy way" to smoke, federal health officials say the devices turn nicotine, which is highly addictive, and other chemicals into a vapor that is inhaled by the user. "The FDA is concerned about the safety of these products and how they are marketed to the public," said Dr. Margaret A. Hamburg, commissioner of the FDA. CNN contacted Florida-based Smoking Everywhere, one of the largest manufacturers of e-cigarettes, after the FDA announcement, and a spokeswoman said the company had no comment. Because e-cigarettes have not been submitted to the FDA for evaluation or approval, the agency had no way of knowing the levels of nicotine or the amounts or kinds of other chemicals that the various brands of these products deliver to the user. That is why the FDA began to test them. The FDA's Division of Pharmaceutical Analysis analyzed the ingredients in a small sample of cartridges from two leading brands of e-cigarettes. In releasing its information, the FDA did not identify the two companies, but said in one sample, diethylene glycol -- a chemical used in antifreeze that is toxic to humans -- was detected. Other samples detected carcinogens that are dangerous to those who smoke them, the FDA said. The FDA has been examining and seizing shipments of non-U.S.-made e-cigarettes at the U.S. border since summer 2008. To date, 50 shipments have been stopped. The products examined thus far meet the definition of a combination drug-device product under the Federal Food, Drug, and Cosmetic Act. "We know very little about these devices, said Dr. Jonathan Samet, director of the Institute for Global Health at the University of Southern California, "but to say they are healthy -- that's highly doubtful."

Question: "Where did the FDA find the chemical diethylene glycol?"

OPTIONS:
- no
- yes

Answer: "Small sample of cartridges"

Response: yes

The properties of matter depend on the types of atoms that matter is made of. Matter can exist in two forms. It can be a pure substance. This means it is not mixed with anything. It can also be a combination of different substances. This means it can be a mix of different types of atoms. You may recall that atoms differ based on the numbers of protons they contain. Some atoms contain only one proton such as Hydrogen. Other atoms contain many protons. There are many types of atoms. For example, Helium has two protons. An Oxygen atom has eight. Water is composed of a two types of atoms. Water is made of two Hydrogen atoms and one Oxygen atoms. There are only so many types of atoms. These atoms can be mixed into an almost limitless amount of substances. So what do we call a substance that has only a single type of atom?

Question: "What atoms is water composed of?"

OPTIONS:
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- yes

Answer: "Hydrogen and oxygen atoms"

Response: yes

You know that friction also causes heat. Think about when you rub your hands together. It is friction that makes them warm. But why does this happen? Friction causes the molecules on rubbing surfaces to move faster. Faster moving particles have more heat energy. Heat from friction can be useful. Can you think of other places where you might find friction? Friction also lets you light a match. Heat from friction can also cause problems. It can cause a car to overheat. To reduce friction, oil is added to the engine. Oil coats the surfaces of moving parts. This coating of oil makes them slippery. When things are slippery there is less friction. Have you ever seen a sign that says, slippery when wet? This too has to do with friction. Water, like oil, can reduce friction. The wet surface may allow your shoes to slide more easily.

Question: "Why do your hands become warmer when you rub them together?"

OPTIONS:
- no
- yes

Answer: "Because of mass"

Response: no

I had drunk too much, I confess, though we all had. Somehow, Tasha and I began to argue the worth of Solevgrad jazz, as inconsequential a topic as I can imagine. She had studied it in school, so she thought herself as an expert. I once had a neighbor who played it constantly, loudly, and badly, so I thought I knew it better. Malaquez tried to mediate, but I saw him as siding with Tasha. So, I think, did she. The subject shifted from music to Tasha's obsession with fame, undoubtedly by a leap that I made. She had no choice but to follow. (I do not remember any of this well, just now, nor do I care to. Those who are truly curious may look at the last act of "Captured Moments.") I remember suggesting, with characteristic tact, that she add Emil to her small list of major accomplishments. Malaquez glanced away, embarrassed. Tasha looked at me as if to say, "I will." She said, "I feel sorry for you, Nardo. I'll see Emil home." "Yes," I said, "Do that," and did not care what she did, or why. Emil asked, "You're all right?" I muttered something he must have interpreted as assent. They both walked up to Emil's home while I watched the scarlet moonlight ripple on distant waves. Disgusted with Tasha but more disgusted with myself, I finally realized she would not return that night and went into The Sleeping Flamingo to drink myself to sleep. She had not come home when I woke in mid-morning.

Question: "What did Nardo's neighbour play constantly, loudly, and badly?"

OPTIONS:
- no
- yes

Answer: "Soul music"

Response:
no