首页
登录
职称英语
How do fireworks produce their colors? Chemicals that give off br
How do fireworks produce their colors? Chemicals that give off br
游客
2023-12-18
37
管理
问题
How do fireworks produce their colors?
Chemicals that give off bright, distinct colors when burned provide the spectacular colors associated with fireworks. Charcoal and iron, for instance, burn brilliant orange. Strontium salts produce red and barium nitrate gives off green. Blue is the most difficult color to produce, and chemists are still searching for a compound that produces a true shade of blue.
Once a manufacturer chooses the colors for a firework, the appropriate chemical powders are compressed into small pellets called stars. These stars are normally packed into a Shell containing gun powder. The shell is then put in a launcher — a close-fitting tube, closed at one end, that has been hammered into the ground. The tube acts like a cannon as the pressure from the exploding gunpowder and expanding gases become trapped behind the shell arid shoot it into the sky.
Depending on the shell design and amount of stars, the firework display varies. A Roman candle, for example, contains only a few stars and shoots them out one at a time, while an aerial shell contains hundreds of stars — each of which leaves a single trail of brilliant color in the sky. For more information about fireworks, contact the National Council on Fireworks Safety, in Washington, D.C., at www. fireworksafety. Com. [br] The "stars" described in the passage are______.
选项
A、shells that are put in a launcher
B、heavenly bodies in the sky
C、brilliant colors produced by fireworks
D、compressed chemical powder
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3283534.html
相关试题推荐
Howdofireworksproducetheircolors?Chemicalsthatgiveoffbr
ToproducetheupheavalintheUnitedStatesthatchangedandmodernizedthe
ToproducetheupheavalintheUnitedStatesthatchangedandmodernizedthe
Asmorepeopleliveclosertogether,andastheyusemachinestoproduceleis
Theproducersofinstantcoffeefoundtheirproductstronglyresistedinthe
Theproducersofinstantcoffeefoundtheirproductstronglyresistedinthe
Theproducersofinstantcoffeefoundtheirproductstronglyresistedinthe
Theproducersofinstantcoffeefoundtheirproductstronglyresistedinthe
Theproducersofinstantcoffeefoundtheirproductstronglyresistedinthe
Thesoundsproducedwithoutthevocalcordsvibratingare______sounds.A、voicel
随机试题
Someconsumerresearchersdistinguish【C1】______"rational"motivesand"emot
[originaltext]AnnCurry:Fora3rdconsecutiveyear,ForbesMagazinehasselect
[originaltext]MynameisNickVujicic,anAustralianwhowasbomwithoutan
根据BrodieX线头片观测显示,下述哪颗牙齿的位置最稳定A.上颌第一恒磨牙
糖尿病最容易受累的神经是:A.脊髓神经根 B.植物神经 C.周围神经 D.
抗甲状腺药物丙基硫氧嘧啶、他巴唑最严重的不良反应是A.永久性甲低 B.药疹
除法律另有规定外,违法行为在一定期限内未被行政机关发现的,不再给予行政处罚。该期
在纯电感电路中有()的特性A.u,i反相 B.L能耗能 C.U超前i
A.易患水痘的人群 B.易患白色念珠菌感染的人群 C.易患白斑的人群 D.
根据《建设工程质量管理条例》的相关规定,下列属于施工单位的质量责任和义务的有(
最新回复
(
0
)