Body Systems: Nervous System: Brain Model

The human brain, at full-size,  is about the size of a full sheet of newspaper (or a pillow case), that's folded up to fit in your skull.

Keep your eyes open for a sheet of newspaper that has a full page ad that has some writing, but a large white space.  When you're born, your brain already has a lot of information stored in it, represented by the writing on the page.  But there's also a lot of room to learn more.  That's the white space on the paper - the brain space that's left to "write" on.
 
It's difficult to put numbers on how "full" one's brain is at birth and how much "room" there is for future learning, as the more you learn the more connections your brain makes.  It appears that there's always room for more learning to take place and that the brain is never "full" (to our current knowledge). 

Sound: The Clanging Hanger

This is a simple demonstration that helps make the point that sound needs something to travel through and that air is not a very efficient material for that purpose.

You only need a wire coat hanger and a long length of string.

Tie the string onto the hanger, so that the hanger hangs from the middle of the string.

Swing the hanger from the string so that it bumps into something (a table, chair, wall, etc.) and take note of the sound it makes.  It's kind of a short, clang-y sound.  Nothing very dramatic or melodic about it.

Now, wrap one end of the string around one of your index fingers and the other end around the other index finger.

Place your fingers in your ears (gently, there's no need to jam them in).

Swing the hanger so that bumps into something once again and take note of the sound it makes.  Louder and more like a gong or large bell ringing.

In the first trial, the sound made when the hanger hit the object had to travel through the air to reach your ear drum.  A lot of the sound was lost on the way to your ear.  In the second trial, the sound vibrations travel from the hanger through the string and your fingers to your ear.  Much less sound energy is lost in route and it makes an audible difference. 

Body Systems: Nervous System: The Importance of Cerebrospinal Fluid

Cerebrospinal fluid (CSF) is the liquid that surrounds your brain and prevents your brain from smashing in to your skull. 

Here's a simple little demonstration that shows just how crucial that fluid is.

You'll need a small container (with a tight-fitting lid), 2 eggs and some water.

Throughout the demonstration, the egg yolk will represent your brain and the container will represent your skull.

Crack one egg into the container and put the lid on. 

Agitate the container - you can just shake it, or you can have a student run a few laps around the room with it for it.

Open the container and observe - scrambled brains!

Clean out the container and crack the second egg into the container. 

This time, before putting on the lid, fill the remaining space in the container with water. 

Agitate the container once again.

Open the container and observe - the egg yolk remains intact.  (The egg what froths up a little bit, making it difficult to see at first, but the whole yolk is there).

The water cushions the egg yolk, just as the CSF cushions your brain. 

Great visual explanation!

Body Systems: Cardiovascular System: Components of Blood

This is a fun way to review the parts that make up blood.

Plasma

Makes up 55% of your blood.  It's a thick liquid that carries that transports food and waste.

Fill a clear glass/jar/beaker 55% full with corn syrup.

Red Blood Cells

Make up 44% of your blood (by volume).  These cells carry oxygen and carbon dioxide throughout your body.

Add candy red hots to the corn syrup, until the container is nearly full.

White Blood Cells
These cells are significantly larger than red blood cells, and there are far, far fewer of them in your blood.  These cells clean-up old blood cells and fight the germs that enter your body.

Add a few mini-marshmallows or white jelly beans to your concoction.

Platelets

These are tiny fragments of cells (some books will just refer to them as cells) are responsible for forming clots when you are cut.

Shake some non-pareils into your blood model.

You now have a cup of "blood".  You'll notice that much of it is liquid, but there's lots of solid in it as well.  You'll also notice lots of red blood cells with the occasional white blood cell popping up.  You have to look really hard to see the platelets - both because of their small size and because of their small numbers. 

Body Systems: Digestive System: Peristalsis

Although gravity aids in the swallowing of food, it doesn't work alone.  Our body actively pushes each food bolus through the digestive system, a process called peristalsis. 

Here's another hands-on model to help your students get a feel for peristalsis. 

The esophagus is made from a leg from a pair of tights or pantyhose.*

Cut the toe off in order to create a tube.

The food bolus is represented by a large plastic egg. 

Place the egg in one end of the tube.  Hold the 'esophagus' vertically so students can see that the food will not just fall through the esophagus - it's going to need a little help.. 

You can return the set-up to the table and have students determine the best way to move the food through the tube. 

They will quickly realize that the egg moves best when the tights/pantyhose above it are squeezed.

This is comparable to the muscles in the esophagus constricting and pushing the food throughout the digestive system.

Of course, we usually consume more than one bolus of food, so you can provide your students with a whole basket of eggs they need to get through the digestive system.  Create several set-ups and have teams of students race!


*Remember the plastic eggs that pantyhose used to come in, back in the day?  Those were the eggs I saw used in this activity originally.  I don't believe you can find those any more (at least without purging your grandmother's house), so I used a large-sized plastic Easter egg.  It works well, though its smaller than the original prop, and as such, you might want to use a child-sized pair of tights to make your esophagus. 

Jello Brain Update!

Remember the free Jell-o brain molds I told you about? 

Well, they arrived a couple of weeks ago. 

For size comparison - that's a 5 year old head it's next too (albeit a rather large 5 year old head....)

I haven't put mine to use yet (have to remember to get more Jell-o at the grocery store...), but my friend Susan got hers and tried it...


Photo from Susan at Learning ALL the Time



Fun stuff! 

If you're interested, you have through Monday (October 31) to get a free mold (only pay $2.95 shipping and handling).  After Halloween, it's regularly priced - $2 + Shipping. 

If you'd like one, head to the Kraft Corner Store!  You'll have a head start on next Hallween, and some interactive Central Nervous System lessons in the meantime!

How Much Does Taste Depend Upon Smell?

Ever noticed that food doesn't seem to have as much flavor when you have a stuffed-up nose? 

A large part of your taste sensations come from smell, so when you can't smell very well, your sense of taste declines as well.  I've used Dum-Dum lollipops for this experiment, since they come in a multitude of flavors and we always seem to have a large number of them around the house after Halloween!

Have students work in pairs to do this experiment.

One student, the taster, closes her eyes and uses one hand to plug her nose.  The other student, the assistant, will then unwrap a randomly chosen lollipop.  He then hands it to the taster, who puts it in her mouth, while keeping her eyes closed and nose plugged.  The taster tries to identify the flavor of the lollipop.  The assistant records the taster's hypothesis. 

After making an initial hypothesis, the taster is then allowed to unplug her nose.  She tries again to identify the flavor of the lollipop.  Again, the hypothesis is recorded by the assistant.

And finally, the taster can open her eyes to view the lollipop, and make any final changes to her flavor guess. 

At that point, the flavor of the lollipop can be revealed and the two students can switch positions.


Of course, you don't have to use lollipops - any candy that comes in multiple flavors will work.  An experiment was put together as a follow-up to a Newton's Apple episode, in which jelly beans are used.  Check out the experiment, the explanation, and make sure you read the "Try This" suggestions at the end - I think I want to try the potato and apple experiment!

Body Systems: Skeletal System: Skeleton Race

Assembling a skeleton relay races are regularly used as Halloween party games, but adding a few extra requirements can turn it into a great review lesson.

Ideally you'd use pieces from snap-together skeletons, but if you don't have those on hand, find an appropriate skeleton to print.  Searching "printable skeleton" will give you a plethora of options, many of which are in pieces that need to be assembled.  Pick one that has appropriate detail for your age group and prepare the pieces.

Divide the class into teams.  The smaller the teams, the more practice each student will get, but it will require more skeletons. 

Each team will need a bowl of skeleton pieces, placed on the front table/teacher's desk.  Each team will work at a separate table/desk.  At that desk they'll need a piece of paper on which to assemble their skeleton and a glue stick.

The first person for each team approaches their bowl of bones and chooses one.  The student studies the bone and has to correctly name the bone before he/she can take it back to the team for assembly.  Once the bone has been brought back to the table, another team member can go retrieve a bone. 

If a student cannot correctly identify the bone they have chosen, it is returned the bowl and the student returns to the team.  The team has to wait out a 15 second penalty before sending the next team member forward. 

Once all the bones have been collected, the students glue the skeleton together.  First team with a correctly assembled skeleton wins! 

Body Systems: Skeletal System: Bone Model

I was inspired by the edible bone models I've come across, to create a non-edible bone model I could keep in the classroom for use year after year, and pull out at a moment's notice.  The supplies are readily available at hardware stores and craft stores.  I hope you find it useful. 

You'll need:
~10" foam pipe insulation
~10" 1 1/2" PVC pipe
Model Magic clay
red yarn
fabric pieces

Begin with the length of foam pipe insulation to use as the spongy bone.  Split the insulation open to reveal the hollow tube in the center, perfect for holding the bone marrow. 

Roll the clay into a snake that fits the center of the pipe insulation.  While you're rolling the clay, embed a length of red yarn in the clay to represent a blood vessel traveling through the marrow.

Slide the completed spongy bone and marrow into the length of PVC pipe.  This is the compact bone. 

Use the fabric to create a tube into which the PVC pipe can slide.  This is the membrane covering the bone. 

I added a few pieces of Velcro, to attach the blood vessels. 

And finally, wrap the outside of the fabric with additional lengths of red yarn - more blood vessels.  (I should add some blue yarn as well....)

I'm really quite pleased with my model.  It can be taken apart and put back together again and again and I think it will be quite useful in the classroom.

Because you usually have to buy 10' lengths of PVC that you have to cut yourself, some of you might be turned off by this project.  I've got extra materials from making my own, as well as easy access to additional supplies, and a willingness to make up some additional models.  If you're interested in purchasing a pre-made model (or several), send me an email and we can discuss the details.

Body Systems: Skeletal System: Edible Bone Model

Do you know what your bones are made up of?  They contain two types of bone tissue: compact bone and spongy bone, bone marrow, and a thin covering.  Blood vessels continuously carry blood to and from the bones. 

If you'd like to make it easier for your students to remember the components of bones as well as their properties, consider having them make an edible model of a bone. 

Pretend that the red yarn is Twizzlers Pull & Peel strings.  I forgot to get them at the grocery store, but had everything else and didn't want to hold things up, so I substituted.

To make your bone model, you'll need:
tortilla
lady fingers
sugar wafers
strawberry jam
Twizzlers Pull & Peel

Place the tortilla on a plate. 

Open the lady fingers and place them along the center of the tortilla.

Spread the lady fingers with the jam.

Lay the licorice down the middle of the lady fingers. 

Sandwich the lady fingers together.  Place the sugar wafers along the sides of the lady fingers.

Wrap the whole thing in the tortilla.

Wrap another piece of licorice around the tortilla.

Your model is complete!  But, before you eat it, make sure you note what each part represents:

Licorice strings are blood vessels.
Strawberry jam is the bone marrow.
Lady fingers are the spongy bone.
Sugar wafers are the compact bone.
The tortilla is the membrane covering the bone.

One version of this activity can be found here, but I first learned about it elsewhere.  I have no idea what the original source is.

Body Systems: Skeletal System: Why You Need Calcium

For this demonstration, you'll need a clean chicken bone* (a drumstick works best) and a large jar filled with vinegar.  You'll also want some way to close the jar, either a lid or some plastic wrap.

Observe the bone, try to bend it (but don't actually do so, you want to keep it in one piece).

Place the bone in the vinegar and cover the jar.

Remove the bone from the vinegar every day for about a week.  Observe and test for flexibility.


Over the course of the week, the bone will become more and more flexible, taking on a rubber-like feel by the end.  The vinegar (acetic acid) breaks down the calcium deposits in the bone, allowing you the opportunity to observe the importance of calcium in maintaining bone strength.

**The next time you have chicken or turkey, you may want to clean the bones and stick them in a resealable bag in the freezer, so you have them when you need one.

Body Systems: Skeletal System: Pasta Skeleton

Skeletons are a common sight around Halloween, and as such, I thought I'd spend a week sharing skeleton/skeletal system/bone activities and lessons you can do with your students.  They're perfect for Halloween mini-lessons or any time your curriculum brings you to those topics. 

First up, pasta skeletons!

The great variety of shapes of pasta in which pasta comes make it a fun (and inexpensive) medium with which to create. 

Provide your students with an assortment of pasta shapes and black construction paper and let them create a skeleton, being sure to include the bones you've required them to learn. 

Another possibility, have them create a more detailed model of one part of the body.  While searching for something else, I found this document, which includes an activity in which students create a model of the bones in the hand using varying sizes of tube-shaped pasta.

The Importance of Brushing Teeth - Part II

Last week we examined the importance of brushing your teeth as a preventative measure to defend against the acid found in foods.  This week we'll examine another way in which regular tooth brushing prevents problems - preventing tooth stains. 

This experiment is run much the same way as last week's.  You'll cover an egg with toothpaste, let it sit overnight and wash off the toothpaste the next day.

The egg is then placed in a cup of coffee (or strong tea).  A second, untreated egg is placed in a second cup of coffee.

The eggs are then allowed to sit and are observed over the course of the next 24 hours - or even longer if you wish.

You will notice that the untreated egg develops darker stains and develops them more quickly than the treated egg. 

You'll also notice that the treated egg does develop stains - the toothpaste does not completely prevent that from occurring, it just slows it. 

Untreated



Treated with toothpaste



So, when you brush your teeth,, you're building up protection against future stains as well as removing older stains.