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02:47:05
Feature
Two Pieces: Luminescence & Smoke Alarms
Lothrop Craddock & CPSC.gov
Luminescence, by Lothrop Craddock
1 Most children are familiar with chemical luminescence. If you have ever played with glow sticks then you can remember that bright glow. This is chemical luminescence. As a child, glow sticks fascinated me. I would bend them all simultaneously to create the brightest glow possible. Afterwards, I would spend what seemed like hours reading under my blanket with these toys. It was always disappointing when the glow ceased.
2 Scientists consider chemical luminescence a cold light because there is little temperature increase. The light emitted is the result of two chemicals mixed together. As the chemical molecules combine, light is produced. In a glow stick, the two chemicals must remain separate until the consumer wants to create the glow. To accomplish this, one chemical is sealed inside a thin glass tube. It is inserted into a larger plastic tube that can bend easily. The space between the glass and plastic portions is filled with the second chemical. In this condition, glow sticks can remain stable for several years.
3 Glow sticks are common in amusement parks, novelty stores, and camping supply stores. Most glow sticks only work for a couple of hours. They contain low amounts of the chemicals needed to maintain a long glow. However, larger glow sticks can maintain their chemical reaction for 12 hours or more. This makes them perfect for night diving and evening strolls. The science of chemical luminescence even found its way into military use. Military-grade glow sticks have special light emissions that are only visible with infrared rays. From birthday parties to combat missions, glow sticks are extremely versatile.
Smoke Alarms, by CPSC.gov
Smoke alarms save lives. They can detect a fire early, and alert consumers, giving them valuable time to escape.
Despite that well-known fact, about two-thirds of fire deaths take place in homes with no smoke alarms or no working smoke alarms, e.g., smoke alarms with no batteries or dead batteries.
When shopping for smoke alarms, consumers should consider the different types of smoke alarms. Both types are effective smoke sensors. Ionization type detectors respond quickly to flaming fires. Photoelectric type detectors respond sooner to smoldering fires. Because both ionization and photoelectric smoke alarms are better at detecting distinctly different yet potentially fatal fires, and because homeowners cannot predict what type of fire might start in a home, CPSC staff recommends consumers install both ionization and photoelectric type smoke alarms in their homes. There are smoke alarms that combine both detection technologies into one unit called dual sensor smoke alarms.
In addition, consider interconnected smoke alarms. Interconnected smoke alarms allow all smoke alarms in the home to sound if one has detected smoke, and they may provide improved protection and offer more time to escape a fire.
Question
Imagine you are writing an essay on the science behind glow sticks and smoke detectors. Which sentences would be the most relevant to quote in your essay to support your points?
Put responses in the correct input to answer the question. Select a response, navigate to the desired input and insert the response. Responses can be selected and inserted using the space bar, enter key, left mouse button or touchpad. Responses can also be moved by dragging with a mouse.
Sentences Relevant to an Essay about Science Sentences Irrelevant to an Essay about Science
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Sentences Relevant to an Essay about Science:
1. Most children are familiar with chemical luminescence.
2. Scientists consider chemical luminescence a cold light because there is little temperature increase.
3. In a glow stick, the two chemicals must remain separate until the consumer wants to create the glow.
4. The science of chemical luminescence even found its way into military use.
5. Smoke alarms can detect a fire early, and alert consumers, giving them valuable time to escape.
6. Both ionization and photoelectric smoke alarms are better at detecting distinctly different yet potentially fatal fires.
7. CPSC staff recommends consumers install both ionization and photoelectric type smoke alarms in their homes.
14 of 1514 of 15 Items
02:47:48
Feature
Before a Painting
James Weldon Johnson
I knew not who had wrought with skill so fine
What I beheld; nor by what laws of art
He had created life and love and heart
On canvas, from mere color, curve and line. 4
Silent I stood and made no move or sign;
Not with the crowd, but reverently apart;
Nor felt the power my rooted limbs to start,
But mutely gazed upon that face divine. 8
And over me the sense of beauty fell,
As music over a raptured listener to
The deep-voiced organ breathing out a hymn;
Or as on one who kneels, his beads to tell, 12
There falls the aureate glory filtered through
The windows in some old cathedral dim.
Question
Principle: a primary truth, assumption, law or belief.
Read the definition of the word "principle." Then choose the sentence that uses it correctly.
Responses
A The principle at my school is going to retire this year.The principle at my school is going to retire this year.
B The principles of democracy are articulated in the Constitution.The principles of democracy are articulated in the Constitution.
C My father always tells me that I shouldn't spend the principle, only the interest.My father always tells me that I shouldn't spend the principle, only the interest.
D If you have questions about dress code, the assistant principle is the person to see.
B The principles of democracy are articulated in the Constitution.
At the Earth’s Core
Edgar Rice Burroughs
1 “Let’s have a look beyond that door, David,” he cried.
2 Together we stepped out to stand in silent contemplation of a landscape at once weird and beautiful. Before us a low and level shore stretched down to a silent sea. As far as the eye could reach the surface of the water was dotted with countless tiny isles—some of towering, barren, granitic rock—others resplendent in gorgeous trappings of tropical vegetation, myriad starred with the magnificent splendor of vivid blooms.
3 Behind us rose a dark and forbidding wood of giant arborescent ferns intermingled with the commoner types of a primeval tropical forest. Huge creepers depended in great loops from tree to tree, dense under-brush overgrew a tangled mass of fallen trunks and branches. Upon the outer verge we could see the same splendid coloring of countless blossoms that glorified the islands, but within the dense shadows all seemed dark and gloomy as the grave.
4 And upon all the noonday sun poured its torrid rays out of a cloudless sky.
5 “Where on earth can we be?” I asked, turning to Perry.
6 For some moments the old man did not reply. He stood with bowed head, buried in deep thought. But at last he spoke.
7“David,” he said, “I am not so sure that we are ON earth.”
8 “What do you mean, Perry?” I cried. “Do you think that we are dead, and this is heaven?” He smiled, and turning, pointing to the nose of the prospector protruding from the ground at our backs.
9 “But for that, David, I might believe that we were indeed come to the country beyond the Styx. The prospector renders that theory untenable—it, certainly, could never have gone to heaven. However I am willing to concede that we actually may be in another world from that which we have always known. If we are not ON earth, there is every reason to believe that we may be IN it.”
Question 1
Using context clues, what is the meaning of the word "myriad" in the second paragraph?
Responses
A very fewvery few
B fragrantfragrant
C vividly colorfulvividly colorful
D an extreme amount ofan extreme amount of
Question 2
Choose two sentences or phrases that give context clues to the meaning of "myriad" as used in the second paragraph.
Responses
A starred with the magnificent splendor of vivid blooms.starred with the magnificent splendor of vivid blooms.
B And upon all the noonday sun poured its torrid rays out of a cloudless sky.And upon all the noonday sun poured its torrid rays out of a cloudless sky.
C we could see the same splendid coloring of countless blossoms that glorified the islands,we could see the same splendid coloring of countless blossoms that glorified the islands,
D Together we stepped out to stand in silent contemplation of a landscape at once weird and beautiful.Together we stepped out to stand in silent contemplation of a landscape at once weird and beautiful.
E Behind us rose a dark and forbidding wood of giant arborescent ferns intermingled with the commoner types of a primeval tropical forest.Behind us rose a dark and forbidding wood of giant arborescent ferns intermingled with the commoner types of a primeval tropical forest.
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Question 1:
D an extreme amount of
Question 2:
C we could see the same splendid coloring of countless blossoms that glorified the islands,
E Behind us rose a dark and forbidding wood of giant arborescent ferns intermingled with the commoner types of a primeval tropical forest.