the end of night
look up at the sky at night. what can you see? before electric lights,people could often see about 2,500 different stars. now,light fills the skies over cities. this is called light pollution. because of it,people only see about ten stars!
most of the time,light helps us. we can see because of it. it gives plants energy. but light isn't always good. we meed times of dark to rest.one hundred years ago,we had those those times of dark. mow the night is like day. some scientists are worried about how this light affects our health. these scientists are studying the effects of light pollution.
other scientists are finding ways to stop light pollution and make our lives better. for example,many streetlights now have covers. the cover focus the light toward the ground. they stop the light from going up into the sky. they also save energy. the covers are a small change,but they can still have a positive effect.
the end of nightlook up at the sky at night. what can you see? before electric lights,people could often see about 2,500 different stars. now,light fills the skies over cities. this is called light pollution. because of it,people only see about ten stars!most of the time,light helps us. we can see because of it. it gives plants energy. but light isn't always good. we meed times of dark to rest.one hundred years ago,we had those those times of dark. mow the night is like day. some scientists are worried about how this light affects our health. these scientists are studying the effects of light pollution. other scientists are finding ways to stop light pollution and make our lives better. for example,many streetlights now have covers. the cover focus the light toward the ground. they stop the light from going up into the sky. they also save energy. the covers are a small change,but they can still have a positive effect.
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