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What Causes the Northern Lights

7th grade nonfiction passage about northern lights: 263 words, seven questions, an answer key and vocabulary.

7th grade nonfiction northern lights 263 words

What Causes the Northern Lights

On a dark, clear night in places such as northern Canada, Alaska, or Norway, the sky sometimes fills with curtains of green light that ripple and drift. This glowing display is called the aurora borealis, or the northern lights. It looks like magic, but it has a scientific explanation that begins ninety-three million miles away, at the sun.

The sun constantly sends out a stream of tiny charged particles called the solar wind. Most of these particles would sweep right past Earth, but our planet is surrounded by a magnetic field, an invisible shield that bends their paths. Earth's magnetic field is weakest near the north and south poles, so the particles are guided down toward those regions.

High above the ground, at a height of roughly sixty miles or more, the particles crash into atoms of gas in the upper atmosphere. Each collision gives an atom extra energy, and the atom gets rid of that energy by giving off a tiny flash of light. Millions of these flashes at once make the glow we see.

The color depends on the gas and the height. Oxygen atoms usually glow green, which is the most common color of the aurora, and sometimes red at great heights. Nitrogen can add blue or purple edges.

The same thing happens at the opposite end of the planet, where it is called the aurora australis, or southern lights. Auroras are strongest when the sun is especially active. Skywatchers who want to see them try to get far from city lights and wait for a dark, cloudless night.

Questions

  1. What is another name for the northern lights? in the text

  2. What is the solar wind? in the text

  3. What does Earth's magnetic field do to the particles? in the text

  4. What color do oxygen atoms usually glow? in the text

  5. What are the southern lights called? in the text

  6. Why are auroras seen mostly near the poles? think about it

  7. Why do skywatchers try to get far from city lights? think about it

Words to know

aurora
a glowing display of light in the night sky
magnetic
having to do with the force that pulls on certain metals
particles
extremely tiny pieces of matter
atmosphere
the layer of gases that surrounds a planet
collision
a crash when two things hit each other
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One passage, three levels

The same topic and facts written three ways, so a mixed class can read and talk about one text. Each group’s sheet shows only a shape; the key says which is which.

● Easier · 258 words · Flesch-Kincaid grade 4.8

On a dark, clear night in northern Canada, Alaska, or Norway, the sky can fill with curtains of green light. The curtains ripple and drift. This glow is called the aurora borealis, or the northern lights. It looks like magic. But there is a science reason, and it starts ninety-three million miles away at the sun.

The sun always sends out a stream of tiny charged particles. This is called the solar wind. Most of the particles would zoom right past Earth. But Earth has a magnetic field. It is an invisible shield that bends their paths. The field is weakest near the north and south poles. So the particles are guided down toward those places.

Far above the ground, about sixty miles up or higher, the particles crash into atoms of gas in the upper atmosphere. Each crash gives an atom extra energy. The atom gets rid of the energy by giving off a tiny flash of light. Millions of flashes at once make the glow we see.

The color depends on the gas and the height. Oxygen atoms usually glow green. This is the most common color of the aurora. At great heights, oxygen can glow red. Nitrogen can add blue or purple edges.

The same thing happens at the other end of the planet. There it is called the aurora australis, or the southern lights. Auroras are strongest when the sun is very active. People who want to see them go far from city lights and wait for a dark night with no clouds.

▲ This passage · 263 words · Flesch-Kincaid grade 8.4

On a dark, clear night in places such as northern Canada, Alaska, or Norway, the sky sometimes fills with curtains of green light that ripple and drift. This glowing display is called the aurora borealis, or the northern lights. It looks like magic, but it has a scientific explanation that begins ninety-three million miles away, at the sun.

The sun constantly sends out a stream of tiny charged particles called the solar wind. Most of these particles would sweep right past Earth, but our planet is surrounded by a magnetic field, an invisible shield that bends their paths. Earth's magnetic field is weakest near the north and south poles, so the particles are guided down toward those regions.

High above the ground, at a height of roughly sixty miles or more, the particles crash into atoms of gas in the upper atmosphere. Each collision gives an atom extra energy, and the atom gets rid of that energy by giving off a tiny flash of light. Millions of these flashes at once make the glow we see.

The color depends on the gas and the height. Oxygen atoms usually glow green, which is the most common color of the aurora, and sometimes red at great heights. Nitrogen can add blue or purple edges.

The same thing happens at the opposite end of the planet, where it is called the aurora australis, or southern lights. Auroras are strongest when the sun is especially active. Skywatchers who want to see them try to get far from city lights and wait for a dark, cloudless night.

■ Harder · 275 words · Flesch-Kincaid grade 10.4

On a dark, cloudless night in places such as northern Canada, Alaska, or Norway, the heavens sometimes fill with shimmering curtains of green light that ripple and drift across the horizon. This spectacular display is called the aurora borealis, or the northern lights. It appears almost magical, yet it has a thoroughly scientific explanation that begins ninety-three million miles away, at the sun.

The sun continually emits a stream of minuscule charged particles known as the solar wind. Most of these particles would sweep straight past Earth, but our planet is enveloped by a magnetic field, an invisible shield that deflects their paths. Because this field is weakest near the north and south poles, the particles are funneled down toward those polar regions.

High above the ground, at a height of roughly sixty miles or more, the particles slam into atoms of gas in the upper atmosphere. Each collision gives an atom a burst of extra energy, and the atom discharges that energy by releasing a tiny flash of light. Millions of these flashes occurring simultaneously produce the glow that we see.

The color depends on both the type of gas and the altitude. Oxygen atoms usually glow green, which is the most common color of the aurora, and they sometimes glow red at very great heights. Nitrogen can contribute blue or purple fringes.

An identical process unfolds at the opposite end of the planet, where it is called the aurora australis, or the southern lights. Auroras are most intense when the sun is especially active. Skywatchers hoping to witness one travel far from city lights and wait patiently for a dark, cloudless night.

Download as one PDF

How to use it

  1. Press Read it big (or B) to put the text on the projector, or Full screen (F) to fill the whole screen.
  2. Ask the questions one at a time and use Show answer when the class has decided. A shows or hides every answer.
  3. Print student copy for the class, or Print with answers for yourself.

Ideas for class

  • Before reading, put aurora, magnetic, particles, atmosphere and collision on the board with their meanings from the Words to know section and have students predict what the text will be about.
  • Read it aloud once while students follow along, then have them reread it alone or with a partner. At a calm 100 words a minute it takes about 3 minutes to read aloud.
  • Use the Read it big button (or B) to put the text on the projector, and Show answer on one question at a time so the class commits to an answer first.
  • Question 6 asks the reader to infer. Ask students to point to the words in the passage that led them to their answer.
  • Ask students to write one question the passage did not answer, then look for the answer in a book or on a classroom screen.
  • Print the student copy for independent work and keep the answer-key copy for yourself.

Related

Questions

What reading level is "What Causes the Northern Lights"?

It was written for 7th grade. It has 263 words and works out to a Flesch-Kincaid grade level of about 8.4. That is a formula's estimate from sentence length and syllables, and it is not a Lexile or a guided reading level, so check it against your students.

What do the questions ask?

There are seven. 5 ask for something the text says directly and 2 ask the reader to work something out from clues. Each has an answer in the key, and the answers are written as a teacher would accept them, not as the only possible wording.

How long does it take to read?

About 3 minutes read aloud at 100 words a minute. For a one-minute fluency check, paste it into the fluency timer and use the word count.

Can I print it?

Yes. Print student copy gives the passage, the questions with lines to write on, and the word meanings. Print with answers gives the same page with the answers filled in. Both are made in your browser.

Is this passage from a published book?

No. It was written for Peabody Teach, so there is no book to buy and no login to read it.

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