Skip to the content
Peabody TeachFor teachers and grown-ups

Why You Stop Smelling Your Own House

8th grade nonfiction passage about sensory adaptation and smell: 269 words, six questions, an answer key and vocabulary.

8th grade nonfiction sensory adaptation and smell 269 words

Why You Stop Smelling Your Own House

Walk into a friend's home and you may notice its smell at once, perhaps coffee, a pet, or a scented candle. After ten minutes, the smell seems to vanish. Meanwhile, your friend, who lives there, hardly notices it at all. The explanation is a process called sensory adaptation, and it is not a failure of the nose. It is a feature.

Smell begins high inside the nose, where a patch of tissue holds millions of receptor cells. When odor molecules drift in with the air, they fit into receptors on these cells, much as keys fit into locks. The cells then send signals to the olfactory bulb at the front of the brain, which passes the message along so that the brain can identify the scent.

If a smell continues unchanged, however, the receptors respond less and less, and the brain pays less attention to the steady signal. The nose is not worn out. It is tuned for change. Noticing something new, such as smoke or spoiled food, matters more than keeping track of an odor that has been present all along. The brain turns down the volume on whatever stays the same.

Adaptation works for other senses too. After you put on a watch, the pressure on your wrist fades from your awareness, and your eyes adjust when you walk into a bright room. A few minutes in fresh air restores your sensitivity to smell. It is also why safety experts recommend smoke and gas detectors rather than trusting your nose alone, since a smell you have lived with for a while may no longer reach your attention.

Questions

  1. Where does the sense of smell begin? in the text

  2. How do odor molecules fit into the receptors? in the text

  3. Where do the signals go after the receptor cells? in the text

  4. Why does the brain ignore a smell that never changes? think about it

  5. Why do safety experts recommend smoke and gas detectors? think about it

  6. What restores your sensitivity to smell? in the text

Words to know

adaptation
a change that makes a sense or body part fit its surroundings
receptor
a cell part that detects a certain signal or substance
olfactory
having to do with the sense of smell
molecules
extremely tiny pieces that make up all matter
sensitivity
how easily something notices small changes
Share

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 · 231 words · Flesch-Kincaid grade 2.8

Step into a friend's home and you smell it right away. Maybe it is coffee, a pet, or a candle. Ten minutes later, the smell is gone. Your friend hardly notices it at all. This is called sensory adaptation. It is not a problem with your nose. It is a useful feature.

Smell starts high inside the nose. A patch of tissue there has millions of receptor cells. Odor molecules float in with the air. They fit into the receptors like keys in locks. The cells send signals to the olfactory bulb at the front of the brain. The brain then knows what the smell is.

But if a smell stays the same, the receptors answer less and less. The brain pays less attention to it. Your nose is not worn out. It is tuned for change. A new smell, like smoke or spoiled food, matters more than an old smell that has always been there. So the brain turns the volume down on what stays the same.

Other senses do this too. You stop feeling a watch on your wrist. Your eyes adjust to a bright room. A few minutes in fresh air gets your sense of smell back. This is why experts want smoke and gas detectors in homes. You cannot always trust your nose, because it may stop noticing a smell that has been around for a while.

▲ This passage · 269 words · Flesch-Kincaid grade 7.1

Walk into a friend's home and you may notice its smell at once, perhaps coffee, a pet, or a scented candle. After ten minutes, the smell seems to vanish. Meanwhile, your friend, who lives there, hardly notices it at all. The explanation is a process called sensory adaptation, and it is not a failure of the nose. It is a feature.

Smell begins high inside the nose, where a patch of tissue holds millions of receptor cells. When odor molecules drift in with the air, they fit into receptors on these cells, much as keys fit into locks. The cells then send signals to the olfactory bulb at the front of the brain, which passes the message along so that the brain can identify the scent.

If a smell continues unchanged, however, the receptors respond less and less, and the brain pays less attention to the steady signal. The nose is not worn out. It is tuned for change. Noticing something new, such as smoke or spoiled food, matters more than keeping track of an odor that has been present all along. The brain turns down the volume on whatever stays the same.

Adaptation works for other senses too. After you put on a watch, the pressure on your wrist fades from your awareness, and your eyes adjust when you walk into a bright room. A few minutes in fresh air restores your sensitivity to smell. It is also why safety experts recommend smoke and gas detectors rather than trusting your nose alone, since a smell you have lived with for a while may no longer reach your attention.

■ Harder · 285 words · Flesch-Kincaid grade 10.2

When you step into a friend's home, you may detect its characteristic smell immediately, whether it is brewing coffee, a family pet, or a scented candle. Within ten minutes, however, that smell appears to have vanished, while your friend, who lives there every day, scarcely registers it at all. The explanation is a process known as sensory adaptation, which is not a defect of the nose but rather a valuable feature of it.

Smell originates high inside the nose, where a patch of tissue contains millions of receptor cells. When odor molecules drift in with the air, they fit into receptors on these cells much as keys fit into locks. The cells then transmit signals to the olfactory bulb at the front of the brain, which relays the message so that the brain can identify the scent.

If a smell persists without changing, though, the receptors respond progressively less, and the brain devotes less attention to the unchanging signal. The nose has not become worn out. It is tuned for change. Noticing something new, such as smoke or spoiled food, matters far more than keeping track of an odor that has been present all along, so the brain effectively turns down the volume on whatever stays constant.

Adaptation operates in other senses as well. Once you put on a watch, the pressure against your wrist fades from your awareness, and your eyes adjust when you enter a brightly lit room. A few minutes in fresh air restores your sensitivity to smell. This is also why safety experts recommend smoke and gas detectors instead of relying on your nose alone, since a smell you have lived with for a while may no longer command your attention.

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 adaptation, receptor, olfactory, molecules and sensitivity 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 4 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 "Why You Stop Smelling Your Own House"?

It was written for 8th grade. It has 269 words and works out to a Flesch-Kincaid grade level of about 7.1. 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 six. 4 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.

Nothing you do here is sent to us. No sign-in, no ads.