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Baffling Body Behaviors.

Everyone's body is different and yet the same in many ways. Every day your body does lots of amazing things that you never even have to think about. Some of them are very strange and even baffling!

Strange Things Your Body Does

Do you ever wonder why you always close your eyes when you sneeze? Why does scratching make an itch feel better? Why doesn't it hurt to get a haircut? Why does it hurt on only one side when you sometimes run very far? Here are 2 body behaviors that will really baffle you. Try them right now.

Close your eyes and look upward as if you are trying to see inside your forehead. Now try to open your eyes. Hmmm ...

Next, put your hands together with your palms touching. Fold down all of your fingers except the ring fingers. Have a friend put a penny between the tips of your ring fingers. Now, try to drop the penny. Weird!!!

We're Born With It -- or Not!

Scientists can explain some of the strange things your body does, but not all of them. Some of us are born with the ability to do certain unusual things. For instance, can you wiggle your ears or fold the edges of your tongue together like a taco? If you can't, you can never teach yourself how -- no matter how long you practice.

Some of these strange abilities depend on the way our body parts work together. Your shape and size, as well as your strength, flexibility, and balance, make a difference in what you are able to do. For instance, some people can do the splits or leap high enough to hang on the rim of a basketball hoop. Can you think of some things that you can do that some of your friends can't?

Scientists are always trying to find out more about how our bodies work ... like what our appendix is really for and why we cry tears when we're sad. These are mysteries waiting to be solved!

DID YOU KNOW??

Your jaw muscle is the strongest muscle in your body. Its biting force is 150 pounds per square inch.

DID YOU KNOW??

You make enough body heat in 1 day to power a light bulb for 36 hours.

DID YOU KNOW??

You grow a new set of skin cells every 2 weeks.

DID YOU KNOW??

Why does your skin get wrinkled in the bathtub? Water gets into the inner layers of your skin, making it swell up and wrinkle.

DID YOU KNOW??

Shivering helps warm you up by making your muscles tighten and loosen again and again. This gives off heat.

Vocabulary

A word find is like an optical illusion. It tricks your eyes. Try these.
baffle wonder
body itch
behaviour weird
born cry
amazing


The words can go across, down, backwards, up, and diagonally.

DID YOU KNOW??

During your lifetime, your hair will grow about 7 miles (11 km).

DID YOU KNOW??

Your eye muscles move about 100,000 times a day!

DID YOU KNOW??

Your eyes make about a gallon (4 liters) of tears each year!

[ILLUSTRATION OMITTED]

Stare at the pupil in this eye while bringing this page up to your nose. How many eyes do you see?

Which line is longer? Can you believe your eyes?

They are the same length. Measure and see.

Weekly Lab

Sometimes it can be hard for your body to do simple things when your brain is receiving mixed-up messages.

You need: your hands, a partner

Step 1: Shake your hands for a few seconds.

Step 2: Cross them at the wrists.

Step 3: Flip your hands around so that the palms touch. Fold your fingers together.

Step 4: Slowly move your folded hands down and around toward your stomach. Bring them up so that they are just below your chin.

Step 5: Now have a friend point to a finger without touching it. Try to lift only that finger!

[ILLUSTRATION OMITTED]

DID YOU KNOW??

About 75% of the dust in your home is made of dead skin cells!

DID YOU KNOW??

You lose 50,000 skin cells every minute.

DID YOU KNOW??

It takes:

17 muscles to smile :-)

43 muscles to frown :-(

72 muscles to speak :-o

Here's Why! (Body Baffler Explanations for activities in your Science Weekly)

Tongue Twisters

A good tongue twister has words with consonants and vowels that employ opposing muscles in your mouth. Try the tongue twister "unique New York." This phrase first makes you pucker your lips with your tongue thrust forward. Then it stretches your lips into a grin with your tongue pulled back. Finally, it makes your lips pucker up again to finish. Most tongue twisters should be pronounced very fast and repeated at least 3 times.

Depth Perception

In order to perceive how far away things are, you need binocular vision (vision from two separate vantage points). Having two sources of information helps the brain calculate the distance to an object. With one eye shut, half of the visual cues are missing. Practice does help with this trick. Over time, you can learn how to compensate for using just one eye.

Trapped!

There are two reasons why an adult will be trapped in a chair when someone holds a finger to their forehead: gravity and center of balance. Sitting back in a chair with your back straight and your feet directly under your knees prevents shifting your center of gravity over your feet, so that your thighs can lift you up. Your thigh muscles are just not strong enough to compensate for this balance problem. Having a finger pushing against your forehead makes this even more difficult.

Zombie Arms

When you push your arms up against a doorway frame, you are tightening and contracting the muscles all along your arms. When you step out of the doorway and relax, your arm muscles are so used to contracting that, for a short while, they continue to lift up your arms.

Eye Opener

The muscles that open and close your eyelids are the same ones that pull your eyeballs upward when you try to "look at the inside of your forehead." Because your muscles are already engaged in looking up, they can't be used to open your eyelids at the same time.

Fingertip Coin Release

The ligaments of your ring fingers are attached to the connective tissue of the other fingers. They cannot move independently of your other digits. When the middle fingers are immobilized, the ring fingers are also.

Easy Money

Like the "Trapped!" activity, this is based on center of balance versus gravity. When bending forward to reach the money, you shift your center of gravity forward. To keep your balance, you would have to move your feet forward ... BUT you are not allowed to do this by the rules of the trick, which require you to keep your heels against the wall.

Are You Right-eyed or Left-eyed?

Just as most people have a hand and foot they use preferentially, they also have a preferred eye. Usually, the dominant eye will be on the same side of the body as your dominant hand. Images seen with both eyes are sent more strongly to the visual cortex of the brain from the dominant eye. When the dominant eye is shut and the less dominant eye is open, the image shifts slightly, outside of the circle made by your thumb and finger.

Don't Lift a Finger

Even though your eyes can plainly see the finger being chosen, because your hands are reversed, lifting it up is not automatic. Before you can perform the task, your brain must go through additional steps to process the information, because your hands are reversed and the signals are not straightforward. This slows the reaction process. Also, each side of your brain controls the opposite side of your body. With your hands reversed, messages sent to the correct muscles all have to be crossed over in the medulla to what appears to your eyes to be the "wrong" side. Very baffling for your brain, to be sure.

Forehead Back-words

Writing your name on a piece of paper held to your forehead, results in mirror writing. The placement of the paper produces a confused image in your brain.

DID YOU KNOW??

You make enough body heat in 1 day to power a light bulb for 36 hours.

Level Pre-A

Main Concepts: There are many things about the human body that make us wonder.

Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Picture Activity

Ask your students what the children in the pictures are doing. Have them suggest reasons and explanations for each one. Explain that scientists do the same thing when they wonder about something. They suggest explanations, and then they do experiments to test out their ideas.

Vocabulary

First have them trace the dotted letters "b" and "s." Then go over all the words and have them try to say each tongue twister 3 times fast. See TN Background -- Tongue Twisters.

Weekly Lab

This lab demonstrates that you need 2 eyes for accurate depth perception. Have your students stand up and stretch out their arms as far as they can to the side without locking their elbows. With their arms apart, have them point their index fingers toward each other. Then with both eyes shut, ask them to try to bring their index fingers together, so that they touch tips. Next, have them try it with one eye open. They will have difficulty both times. Finally, have them try this with both eyes open. This should be a simple task because their depth perception has been restored by using both eyes. This activity becomes easier with practice. See TN Background -- Depth Perception.

Weekly Problem

This activity looks at 4 baffling body behaviors that are inherited. In other words, each of these traits are things you are born with. They cannot be learned. Make a large class chart on the board like the one in this activity. Demonstrate or explain what each trait will look like. Then have them try it. When they are finished, have them put a check on the "I can" or "I can't" circles by each one. Then fill-in the class chart on the board with their results. Finally have them copy the class results onto their own charts in the boxes. (This activity can also be done at home with family and friends.)

Storytelling

Have them carefully look at the 3 pictures and describe what is happening in each scenario. Encourage them to use their imaginations to tell a story based on one of these amazing imaginary body behaviors. As an extension, have them invent an exaggerated or imaginary body behavior story of their own. Have them answer questions like "What could they do? What did it feel like, etc.?"

Home Base

You need: a straight-backed chair. In this activity, your students will use gravity and balance to keep an adult "trapped" in a chair. The adult should sit well back in the chair with their feet directly below their knees and hands folded in their lap. Be sure the adult sits up straight and tall. The student should place his or her index finger (or first 2 fingers) firmly against the adult's forehead. The adult will then try to get up (no use of hands allowed!) As long as the student can keep the adult's upper body from leaning forward, the adult will remain "trapped" in the chair. See TN Background -- Trapped! for more information.

Challenge

This activity measures reaction time. It will show how much time it takes for the brain to receive information from the eyes and send a message to the fingers to catch the test strip. Have pairs of students take turns dropping and catching the test strip. Make sure that the catchers' fingers are only about half an inch apart and are positioned near the very bottom of the strip of paper. The one who drops the strip should do so quickly and without warning.

DID YOU KNOW??

During your lifetime, your hair will grow about 7 miles (11 km).

Level A

Main Concepts: There are many things about the human body that make us wonder. Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Picture Activity

Ask your students what the children in the pictures are doing. Have them suggest reasons and explanations for each one. Explain that scientists do the same thing when they wonder about something. They suggest explanations, and then they do experiments to test out their ideas.

Vocabulary

First have them write in the letters "b," "s," and "r." Then go over all the words and have them try to say each tongue twister 3 times in a row as fast as they can. See TN Background -- Tongue Twisters.

Weekly Lab

See TN Level Pre-A -- WEEKLY LAB.

Weekly Problem

This activity looks at 5 baffling body behaviors that are inherited. In other words, each of these traits are things you are born with. They cannot be learned. Make a large class chart on the board like the one in this activity. Demonstrate or explain what each trait will look like. Then have them try it. When they are finished, have them put a check on the "I can" or "I can't" circles by each one. Then fill-in the class chart on the board with their results. Finally have them copy the class results onto their own charts in the boxes. (This activity can also be done at home with family and friends.)

Writing for Science

Have them carefully look at the 3 pictures and describe what is happening in each scenario. Encourage them to use their imaginations to write a story based on one of these amazing imaginary body behaviors. As an extension, have them invent an exaggerated or imaginary body behavior story of their own. Have them answer questions like "What could they do? What did it feel like, etc?"

Home Base

You need: a straight-backed chair. In this activity, your students will use gravity and balance to keep an adult "trapped" in a chair. The adult should sit well back in the chair with their feet directly below their knees and hands folded in their lap. Be sure the adult sits up straight and tall. The student should place his or her index finger (or first two fingers) firmly against the adult's forehead. The adult will then try to get up (no use of hands allowed!) As long as the student can keep the adult's upper body from leaning forward, the adult will remain "trapped" in the chair. See TN Background -- Trapped! for more information.

Challenge

This activity measures reaction time. It will show how much time it takes for the brain to receive information from the eyes and send a message to the fingers to catch the test strip. Have pairs of students take turns dropping and catching the test strip. Make sure that the catchers' fingers are about half an inch apart and are near the bottom of the strip of paper. The one who drops the strip should do so quickly and without warning.

Level B

Main Concepts: There are many things about the human body that make us wonder. Scientists do not have answers to all the things that baffle us about our bodies. Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Vocabulary

Answers: b, s, r. Challenge your students to figure out what letter is missing from each tongue twister and then write it in. Have them try to say each tongue twister 3 times as fast as they can. Suggest that they bring in other tongue-twisters to class. See TN Background -- Tongue Twisters for more information.

Weekly Lab

Your students should take turns standing in a doorway. and pushing up against the door frame with the backs of their hands. After 30 seconds or so, have them step away from the doorway and relax their arms. Their arms will rise up on their own for the next few seconds. See TN Background -- Zombie Arms for more.

Weekly Problem

See TN Level A -- WEEKLY PROBLEM.

Writing for Science

Have them carefully look at the 3 pictures and describe what is happening in each scenario. Encourage them to use their imaginations to write a story based on one of these amazing imaginary body behaviors. In addition, have them make up their own imaginary "baffling body behavior." Have them write about and illustrate it.

Home Base

The first activity demonstrates that you need 2 eyes for accurate depth perception. Have your students stand up and stretch out their arms as far as they can to the side without locking their elbows. With their arms apart, have them point their index fingers toward each other. Then with both eyes shut, ask them to try to bring their index fingers together, so that they touch tips. Next, have them try it with one eye open. They will have difficulty both times. Finally, have them try this with both eyes open. This should be a simple task because their depth perception has been restored by using both eyes. See TN Background -- Depth Perception. In the second activity, You need: a straight-backed chair. Your students will use gravity and balance to keep an adult "trapped" in a chair. The adult should sit well back in the chair with their feet directly below their knees and handsfolded in their lap. Be sure the adult sits up straight and tall. The student should place his or her index finger (or first 2 fingers) firmly against the adult's forehead. The adult will then try to get up (no use of hands allowed!) As long as the student can keep the adult's upper body from leaning forward, the adult will remain "trapped" in the chair. See TN Background -- Trapped! for more.

Challenge

This activity measures reaction time. It will show how much time it takes for the brain to receive information from the eyes and send a message to the fingers to catch the test strip. Have pairs of students take turns dropping and catching the test strip. Make sure that the catchers' fingers are only about half an inch apart and are positioned near the very bottom of the strip of paper. The one who drops the strip should do so quickly and without warning.

Level C

Main Concepts: There are many things about the human body that make us wonder. Scientists do not have answers to all the things that baffle us about our bodies. Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Vocabulary

Answers: ACROSS -- baffle, cry, itch, strange DOWN -- body, weird, amazing BACKWARDS -- wonder DIAGONALLY -- behavior. The "eye" optical illusion occurs because both eyes are staring at something out of focus. As each eye works to focus on the image, it appears to double and you see 2 eyes.

Weekly Lab

See TN Level B -- WEEKLY LAB. Have them try this trick with just one arm at a time. Was there any difference?

Weekly Problem

This activity measures reaction time. In this case it will show how much time it takes for the brain to receive information from the eyes and send a message to the fingers to catch the ruler. Have pairs of students take turns dropping and catching the ruler. Make sure that the catchers' fingers are only about half an inch apart and are positioned near the bottom of the ruler. The person who drops the ruler should do so suddenly and without warning. This skill will improve with practice and they will see that in their recorded results. The answer to the eye trick is that both lines are the same length. The ends of the arrows create the false impression in your brain that the lines are of different lengths.

Writing for Science

Answers: b, s, r, t, f. After figuring out what letter is missing in each tongue twister line, have them try to say each one 3 times in a row as fast as they can. Suggest that they bring in other tongue twisters to class. See TN Background -- Tongue Twisters.

Challenge

This activity uses center of balance and gravity to ensure that the money cannot be picked up from

the floor. The one who has been challenged to pick up the money should stand with their heels against the wall. They will not be able to bend over. See TN Background -- Easy Money for more information.

Puzzle

The first activity can identify which is their more dominant eye. Have them first look at the X with both eyes open. Now, without moving their heads or the circle made by their fingers, they should close the right eye and look for the X. They will then open their right eye and close the left one. If the X was visible through the circle when the right eye was closed, then the left eye is stronger or dominant. If the X was visible through the circle when the left eye was closed, then the right eye is dominant. See TN Background -- Are You Right-eyed or Left-eyed? for more information. For the "touching fingers" activity -- this demonstrates the need to use 2 eyes for accurate depth perception. Have them stand up and stretch out their arms as far as they can to the side without locking their elbows. With their arms apart, have them point their index fingers toward each other. Then with both eyes shut, ask them to try to bring their index fingers together, so that they touch tips. Next, have them try it with one eye open. They will have difficulty both times. Finally, have them try this with both eyes open. This should be a simple task because their depth perception has been restored by using both eyes. See TN Background -- Depth Perception for more information.

DID YOU KNOW??

You lose 50,000 skin cells every minute.

Level D

Main Concepts: There are many things about the human body that make us wonder. Some traits we inherit from our parents, others are skills we learn. Scientists do not have answers to all the things that baffle us about our bodies. Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Vocabulary

Answers: ACROSS -- baffle, itch DOWN -- body, weird, amazing UP -- cry, wonder BACKWARDS -- born DIAGONALLY -- behavior. The first optical illusion occurs because both eyes are staring at something out of focus. As each eye works to focus on the image, it appears to double and you see 2 eyes. The answer to the second optical illusion is that both lines are the same length. The ends of the arrows create the false impression in your brain that the lines are different lengths.

Weekly Lab

See TN Background -- Don't Lift a Finger for a full explanation of this phenomenon.

Weekly Problem

See TN Level C -- WEEKLY PROBLEM.

Writing for Science

Answers: b, s, r, t, f, s. After figuring out what letter is missing in each tongue twister line, have them try to say each one 3 times in a row as fast as they can. Suggest that they bring in other tongue twisters to class. See TN Background -- Tongue Twisters for more information. In addition, being able to fold your tongue into a "taco" is a trait you are born with. Take a survey to see how many in your class can and can't. How many of the "can'ts" can twist their tongues upside down instead?

Body Bafflers

See the TN Background for explanations of these body bafflers.

Level E

Main Concepts: There are many things about the human body that make us wonder. Some traits are inherited and some are learned. Some characteristics result from the way the human body is put together. Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Vocabulary

Answers: ACROSS -- baffle, itch DOWN -- body, weird, amazing UP -- cry, wonder BACKWARDS -- born DIAGONALLY -- behavior. The first optical illusion occurs because both eyes are staring at something out of focus. As each eye works to focus on the image, it appears to double and you see 2 eyes. The answer to the second optical illusion is that both lines are the same length. The ends of the arrows create the false impression in your brain that the lines are different lengths.

Weekly Lab

See TN Background -- Don't Lift a Finger for a full explanation of this phenomenon.

Weekly Problem

This activity measures reaction time. In this case it will show how much time it takes for the brain to receive information from the eyes and send a message to the fingers to catch the ruler. Have pairs of students take turns dropping and catching the ruler. Make sure that the catchers' fingers are only about half an inch apart and are positioned near the bottom of the ruler. The person who drops the ruler should do so suddenly and without warning. Be sure to have them record the results for at least 20 trials before they calculate their average time.

Writing for Science

Explain to your students that scientists often wonder about things in their scientific work. They then propose an explanation and do experiments to test their theory. A theory is an "informed guess" for an unanswered question. Have your students look at the list of questions and propose a theory to explain one. They can also suggest how their theory could be tested in an experiment. See the TN Background for some theories about these body behaviors.

Body Bafflers

See the TN Background for explanations of these body bafflers.

DID YOU KNOW??

Your jaw muscle is the strongest muscle in your body. Its biting force is 150 pounds per square inch.

Level F

Main Concepts: There are many things about the human body that make us wonder. Some traits are inherited and some are learned. Some result from the way the human body is put together. Scientists do not have answers to all these baffling body behaviors. Note: The explanations for the Body Bafflers are found in the Background section of the Teaching Notes.

Weekly Lab

Lab A -- See TN Background -- Don't Lift a Finger for an explanation of this trick. Lab B -- Your students will trace over the path through the maze with a finger tip. Then they will place the mirror on the red line above the maze and, while looking only into the mirror, trace the path with a pencil, taking care not to touch any lines. Because the mirror reverses the image to the eye, the hand will have difficulty following the path through the maze. The "eye" optical illusion occurs because both eyes are staring at something out of focus. As each eye works to focus on the image, it appears to double and you see 2 eyes. The answer to the second optical illusion is that both lines are the same length. The ends of the arrows create the false impression in your brain that the lines are different lengths.

Weekly Problem

See TN Level E -- WEEKLY PROBLEM.

Writing for Science

Explain to your students that scientists often wonder about things in their scientific work. They then propose an explanation, and do experiments to test their theory. A theory is a "smart guess" or "informed explanation" for an unanswered question. Have your students look at the list of questions and propose a theory to explain them. You might also wish to have them suggest how their theory could be tested in an experiment. See the TN Background for some theories about these body behaviors.

Body Bafflers

See the TN Background for explanations of these body bafflers.

DID YOU KNOW??

Your eye muscles move about 100,000 times a day!

Weekly RESOURCES

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

* Berger, Melvin and Gilda. Why Don't Haircuts Hurt? New York: Scholastic Books, 1998

* Cobb, Vicki and Kathy Darling. Bet You Can't! New York: Lothrop, Lee & Shepard Books, 1980

* Cole, Joanna and Stephanie Calmenson. Six Sick Sheep: 101 Tongue Twisters. New York: Beech Tree Paperback Books, 1993

* Masoff, Joy. Oh, Yuck! The Encyclopedia of Everything Nasty. New York: Workman Publishing, 2000

* Van Cleave, Janice. The Human Body for Every Kid. New York: John Wiley & Sons, Inc., 1995

Internet Resources

for some optical illusions -- http://www.illusionworks.com http://www.grand-illusions.com http : //www.ads-online.on.ca/illusion/directory.html

from Howard Hughes Medical Institute -- http://www.HHMI.org/senses/a/a110.htm

about your amazing body --

How Stuff Works -- http://www.howstuffworks.com/category-body.htm

Your Gross & Cool Body -- http://kids.discovery.com/ click on Yuckiest Site, go to "Body"

Brain Pop -- http://www.brainpop.com/health/seeall.weml

Ask Dr. Universe -- http://druniverse.wsu.edu/search.asp

Materials Needed for Issue 8 -- Oil Spills

Pre-A, A -- crayons, clear plastic soft drink bottles with caps, water, food coloring, oil, optional -- soap

B -- clear plastic soft drink bottles with caps, oil, water, food coloring, dishwashing liquid, feathers, pieces of fur, soap, optional -- sinks or tubs, spoons, sponges, strainers, paper towels

C -- clear plastic soft drink bottles with caps, oil, water, food coloring, dishwashing liquid, feathers, pieces of fur, soap

D, E -- same as above, plus large roasting pans or tubs, thick yarn, slotted spoons, plastic spoons and forks, paper towels, tape, straw, shredded newspaper, cotton balls, nylon netting, craft sticks, large plastic bags or sheets

F -- large roasting pans or tubs, water, oil, thick yarn, slotted spoons, plastic spoons and forks, paper towels, tape, straw, shredded newspaper, cotton balls, nylon netting, craft sticks, dishwashing liquid, large plastic bags or sheets, sand, small room fans, feathers, pieces of fur

Weekly Problem

Reaction time is the amount of time it takes for a message to get from your brain to your muscles. How fast is your reaction time? Have a friend drop a ruler while you try to catch it. Do it 20 times. Record your results. Then switch places with your partner.

Hint: Be sure to hold the ruler at the 12-inch mark when you drop it.

DID YOU KNOW??

The world's longest hair belongs to Hu Saelao of Thailand. It is 16 feet, 10 inches (51.m) long.

DID YOU KNOW??

Skin color contains melanin. Skin with lots of melanin is dark. Skin with little melanin is pinkish. Skin cells can make more melanin, too. That's what a suntan is.

* How many times did you miss? --

* How fast was your fastest catch? --

What was your most frequent reaction time? --

* Did you get better with practice? --

Distance Time
2 inches 0.101 seconds
4 inches 0.143 seconds
6 inches 0.175 seconds
8 inches 0.202 seconds
10 inches 0.226 seconds
12 inches 0.247 seconds


Writing for Science

Part of a scientist's job is to explain things. Sometimes the answer to a question hasn't been discovered yet. Then scientists may have to give you their theory -- their best guess about why something is the way it is. Write a theory to explain at least one of these questions.

* Why do we cry?

* Why do we yawn?

* Why don't haircuts hurt?

* What are goose bumps for?

DID YOU KNOW??

Hair color comes from melanin. Pure melanin makes hair black or brown. Hair that has sulphur is blond. Hair with iron is reddish.

Body Bafflers

Zombie Arms

Stand in a doorway with your arms hanging straight down. Raise your arms so that the backs of your hands press against the doorway.

Keep pushing hard while you count to 30.

Stop and let your arms relax. What happens? Why?

Depth Perception

Why do we need 2 eyes?

Hold your fingers like this. Close one eye.

Can you make them touch?

Easy Money

Tell a friend they can have your money ... IF they can pick it up.

Have them keep their heels against the wall.

Put the money about a foot in front of them.

They will not be able to bend over.

Trapped!

You can keep an adult trapped in a chair with just 1 finger.

Have an adult sit all the way back in a chair. Tell them to keep their back straight and their feet flat on the floor.

Put your finger on their forehead. Tell them to try to stand up. They're trapped!

Are You Right-eyed or Left-eyed?

Make an X on paper and hang it on the wall. Stand on the other side of the room. Make an "OK" sign with your thumb and finger and look through it at the X with both eyes open.

Then, without moving your head, first close your right eye and look for the X. Then, open the right eye and close the left.

With which eye could you still see the X inside your fingers? That's your dominant or hardest-working eye.

DID YOU KNOW??

A rope made from 1,000 hairs would be strong enough to hold 350 pounds (159 kg). 10,000 hairs could pick up a car.

DID YOU KNOW??

Lips are more red than other places on your body because the skin is very thin there. This thin skin lets the blood below show through!

Baffling Body Behaviours

TEACHING NOTES (TN) Supplement to Science Weekly Publication Pre-A through F

Background

You could ask a hundred people and they would all agree -- the human body is wonderful and often weird. Everyone's body is different, and yet in many ways the same. We all marvel at our bodies and sometimes wonder at some of the unusual and often unexplainable things they can do.

We are born with many attributes that make us unique, from your eye color to your temperament. How do these characteristics and traits come about? Inside of each of our cells is a code made of DNA (or deoxyribonucleic acid (dee-ox-ee-RYE-boh-noo-clay-ic acid). This genetic material serves as a kind of recipe for making us into a unique, one-of-a-kind, very special human being. Our DNA code tells our growing cells how to become ear lobes, brain cells, toenails, or heart muscle -- whatever parts our growing bodies need. Each person's unique recipe determines whether that person will have blue eyes, curly hair, freckled skin, or big feet! It also determines whether you will like the taste of broccoli, whether you can roll your tongue into a U shape, and if you can wiggle your ears. No two people on Earth are exactly the same.

Some of the things our bodies can do are downright baffling. These abilities are sometimes determined by the way the human body is constructed and how the parts work together. Your shape and size and your strength and balance all have an effect on the way your body operates. For example, most people know someone who can lift an extraordinarily heavy load or dance the "limbo" by bending effortlessly backwards under a pole. Some of the "body bafflers" highlighted in this issue are the result of a "displaced center of gravity." See Trapped! and Easy Money on Page 3 for examples of how our shape and strength and balance interact with gravity for a puzzling effect. The way in which our body parts work together (sometimes inside and sometimes outside) can also produce some unusual and mysterious results. See Fingertip Coin Release and Don't Lift a Finger also on Page 3.

Experience and learning also help make each person a unique individual, different from everybody else. Think about all of the things your body must learn to do between the time you are born and adulthood. We learn to eat, crawl, walk,-run, skip, and climb. We also learn skills and habits through sports and recreation training and through artistic expression and activities. Have you ever wondered why some people can do the splits with ease or dunk a basketball with great precision time and again? These somewhat baffling abilities are learned. They will develop and grow with continued practice. All of these unique "abilities" help make you the special, distinctive person that you are.

There are some things about our bodies that no one can explain. Scientists are still studying them and conducting research projects to find out more. For instance, why does it feel good to scratch an itch? What is the appendix really there for? Why do we cry? Scientists have some pretty good guesses, but no one knows for sure just yet. The activities your students will try out in this issue of Science Weekly may answer some of their questions ... but, they may also make them wonder even more at the amazing abilities of their bodies!

DID YOU KNOW??

It takes:

17 muscles to smile :-)

43 muscles to frown :-(

72 muscles to speack :-o

Who Knows? Body Baffler Theories

Why do you automatically close your eyes when you sneeze? No one really knows, but it certainly must help keep your eyes from popping out of your head, as the air flies out of your mouth and nose at an amazing 100 miles (160 km) per hour every time you sneeze)

Why does scratching make an itch feel better? An itch is an irritation that is not quite classified as painful. The itch sensation, though, is carried to the brain by the pain-nerve system. Scientists think we scratch to create a slightly more painful sensation in the nerves that then overrides the itch message. It may also scrape away the irritating material from the skin or push away an insect that was causing the irritation.

What are tears for? No one knows why we cry tears when we're sad. Some scientists think tears help rid our bodies of the chemicals that make us feel sad and stressed. No one has been able to identify these chemicals yet.

What makes us yawn? No one knows for sure why we yawn either. Some scientists believe if our bodies need more oxygen at a particular time, our brains trigger something that makes us take this special deep breath Other scientists think that yawning may just help get rid of too much carbon dioxide in our bloodstream.

What makes hair curly? The "shape" of your hair strand determines whether you will have wavy, curly, or straight hair. Curly hair has flat strands, wavy hairs are oval, and straight hairs are round.

Why don't haircuts hurt? It doesn't hurt to get a haircut, because your hair is made mostly of keratin, a type of dead skin cell. There are no "nerves" in your hair, so you don't feel anything. Cutting your nails doesn't hurt either, for the same reason. The living part of your hair is under the skin of your scalp. That's why it does hurt when someone pulls your hair.

What are goose bumps? Long ago when early people were hairier, goose bumps lifted the hairs on their bodies to make a warm blanket of trapped air near the skin. Some scientists say this also made them look bigger and scarier when an enemy was threatening them (like when a scared cat puffs itself up).

Why do you sometimes get a "stitch" in your side? Most theories suggest that repeated hard breathing puts stress on our diaphragm muscle (the "floor" of our rib cage). This results in what we feel as a painful "stitch" in the side of our bodies. The cure for this is to change your breathing Pattern and your posture. Some sports experts think that because your liver bounces up and down when you run, the ligament near your liver may be pulling repeatedly at your diaphragm. If you stop running and use your right hand to lift up the area around your liver, this may help relieve a painful "stitch."

Why do we hiccup? Our diaphragm muscle tightens when we breathe in, and loosens when we breathe out. Sometimes the diaphragm jerks or spasms. This is a hiccup. Nobody knows exactly what makes the diaphragm jerk, but it can happen when you eat too quickly or drink too many carbonated soft drinks.

National Science Education Standards

Unifying Concepts and Processes (K-8)

* Systems, order, and organization

* Evidence, models, and explanation

* Constancy, change, and measurement

* Evolution and equilibrium

* Form and function

Standard A: Science as Inquiry (K-8)

* Abilities necessary to do scientific inquiry

* Understanding about scientific inquiry

Standard C: Life Science (K-4)

* The characteristics of organisms

* Organisms and environments (5-8)

* Structure and function in living systems

* Regulation and behavior

* Diversity and adaptations of organisms

Standard F: Science in Personal and Social Perspectives (K-8)

* Personal health

Standard G: History and Nature of Science (K-4)

* Science as a human endeavor (5-8)

* Science as a human endeavor

* Nature of science
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Publication:Science Weekly
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Date:Nov 30, 2000
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