|
Krampf #463 Eggs-ray Vision
|
KRA-@aol.com
|
May 26, 2006 21:19 PDT
|
Robert Krampf's Experiment of the Week
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
This Week's Experiment - #463 Eggs-ray Vision
Greetings from Redding, California. Donna, Omar and I flew out for a day of
shows at the Wheelabrator Energy Day event, and three days of video taping in
the mountains for our FCAT project. It will be a series of 58 science
lessons, aimed at helping students do better on Florida's high stakes science test.
If it is a success, we will then do the same thing for other states. By
next week, we will have a blog (web journal) up, for those of you that want to
keep track of our adventures.
This week's experiment came from trying to hatch some eggs. We are using an
incubator, and hoping to hatch some chicks and ducks. This week, we candled
the eggs, to see if they were developing. Candling is a technique for
looking inside an egg, without breaking the shell. To try this, you will need:
an egg
a bright llight
a cardboard box
a dark room
a small bowl or dish
First, cut a hole about the size of a quarter in the bottom of the cardboard
box. Turn the box upside down, and put the bright light inside. Position
the light so that it is shining up through the hole. Then darken the room and
place the egg over the hold. The light should shine into the egg, making it
glow.
Look carefully at the egg. If you were looking at a fertile egg that had
been incubated for a couple of weeks, you would see a large, dark mass. That
would be the baby chick.
While you won't see that in your egg, you can see a few things. First, you
can see the air cell. It will look like a small bubble at the large end of
the egg, and that is exactly what it is. In a fresh egg, it is small, but if
you keep the egg in the refrigerator for a while, it loses part of its water
and the air cell gets bigger.
You may also see lots of tiny light spots in the shell. Those are pores
that let the egg breath. It lets oxygen get in, and lets carbon dioxide and
water get out.
If you have a very bright light, you may see just a hint of the yolk. That
is about all that you should see by candling, but by breaking the egg, we can
learn even more about the inside. Carefully crack the egg into a small bowl
or dish. Try not to break the yolk.
Look carefully at the inside of the shell. Along the inside of the hard
shell, you should see a thin, skin-like membrane. Actually, there are two
membranes, one inside the other. If you look at the inside of the large end of
the egg, you should see the air cell, in between the two membranes. These
membranes control what goes in and out of the egg, keeping it from drying out, and
helping to keep out microorganisms that would spoil the egg.
Next, look at the egg. Most people are familiar with the white or albumen
(which comes from albus, which is latin for .... you guessed it. White.)
Inside the albumin is the yolk. Many people think that the yolk develops into
the chick, but it does not. Instead, the yolk is a stored food supply to
feed the chick until it hatches. Even if you have a fertilized egg, the part
that will develop into the chick is VERY tiny, so don't expect to see it.
In the albumin, you may also see one or two small, white structures. Again,
many people think that this is the start of the chick. Instead, these are
chalazae, rope-like structures that hold the yolk in the center of the albumin.
By keeping it away from the shell, they protect the yolk from contamination
by any microorganizms that find their way into the egg. That is also why
you should store eggs with the large end up. Since the air cell is an air
bubble, it tries to float upwards. If the large end of the egg is down, the air
cell stretches upwards, bringing it closer to the yolk, which could cause the
egg go bad quicker.
Now that you have dissected the egg, the only thing left to do is to denature
its proteins. To do that, put a little butter into a skillet. Turn the
heat on medium and place the egg into the skillet. The heat will change the
protein of the egg, causing the albumin to change from a clear gel to a firm,
white solid. The yolk will also take on a firm texture. Then add a little
salt and pepper and you have a very nice snack.
Have a wonder filled week.
****************************************
This weekly e-mail list is free from charge. You are welcome to forward it
to friends, print it in your newsletter, repost it on the Internet, etc., as
long as you do not charge for them and my name and e-mail address are
included.
Please forward this e-mail to anyone that you think might enjoy it.
To join the list, send a blank e-mail to: krampf-s-@topica.com
on-line archives are located at:
http://groups.yahoo.com/group/krampf/messages
http://www.topica.com/lists/krampf/read
***************************
Robert Krampf's on-the-road schedule:
My calendar is now on-line. You can see a detailed calendar, with dates,
times, schools, etc. at http://www.krampf.com/m_tour.html
***************************
Check out my web site at:
http://www.krampf.com
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
|
|
 |
|
