An Egg-speriment
Back ground information and
experimental design
Why do astronauts wear space suits?
• Space suits serve as an effective boundary
between the external environment of space
and the internal environment within the space
suit. Without this boundary the astronauts
would die.
What is homeostasis?
• The body’s ability to maintain its internal
environmental conditions despite changes in
the external environment.
How does the human body act as a
container?
• The human body is a large and complicated
container that is made up of many smaller
containers called cells.
• Different cells have different functions.
How big are cells?
• Most cells are so small that they require a
microscope to see them. There are
exceptions. A chicken egg is a single cell. It is
protected by a hard shell surrounded by
several soft membranes.
Anatomy of a chicken cell
The Yolk
• Although the egg is a cell the yolk is not the
nucleus. The nucleus of an egg is located
inside the yolk and is barely visible.
The Shell
• Bumpy and grainy texture
• 17,000 pores in a egg shell
• Egg shell is made of Calcium Carbonate
(CaCO3)
• Semi permeable- air and moisture can pass
through
• Has a coating that keeps out bacteria and dust
Inner and outer membranes
• Located between the shell and the egg white
• Provide defense against bacteria
• Strong- made of keratin (protein in human
hair)
Air Cell
• A air space that forms after the contents of
the egg cools after being laid.
• Usually at the large end of the egg
• Grows as the egg gets older.
Albumin
• Egg white
• Comes from the Latin Albus meaning “white”
• Contains 4 alternating layers of thick and thin
albumin, made up approximately 40 different
proteins.
Chalazae
• Opaque ropes of egg white
• Hold the yolk near the center of the egg
• Most visible when the egg is the freshest
Vitelline Membrane
• The clear casing that encloses the yolk
Quantitative observations
• Observations that involve results that are
measureable with standard scales
• Examples- Mass (g), temperature (°C), volume
(cm3), time (s)
Qualitative
• Involve descriptions and results that are
measureable with non-standard scales
• Examples- hot or cold, color- red or pink
Controlled Experiment
• An experiment in which all but one variable is
controlled.
Summary
• Write a summary for your CN.
• Example Summary:
• The human body is able to maintain a
constant internal environment despite
changing external conditions. Cells are like
individual compartments. By studying cells
we can record how they react to changing
external conditions.
DO NOW: 9/23/14
Take down the following notes
• Solution- a uniform mixture of two or more
substances.
• Solute- the dissolved substance in a solution
• Solvent- the substance that does the dissolving.
• Isotonic solution- concentration of solutes inside and
outside the cell are equal
• Hypertonic solution- the concentration of solutes
outside the cell are greater than on the inside
• Hypotonic solution- the concentration of solutes
outside the cell is less than the concentration inside
the cell.
Experimental Design
• Design a controlled experiment that tests the
effect of the external environment on the
internal environment of an egg.
• Read the “Eggs-periment Protocol” (p.154)
Procedures (Protocol)
1. Remove the shells from 3 chicken eggs by
soaking the eggs in vinegar for 72 hours.
2. Carefully pat each egg dry, get the starting
mass of each egg and record in a data table
3. Label each cup with the appropriate solution:
– Distilled water, 50% corn syrup solution, ______?
4. In your data table write a prediction about
the effect of the environment on each egg.
Sample Table
Table 1.
EGG
1
2
3
Environment
Distilled Water
50% Corn
Syrup Solution
?
Starting
Mass
(g)
Prediction
Final
Mass
(g)