Eggshells

Gaines, Patricia A.             O. W. Holmes School
                                471-4625             
                                     

Objectives:

I.  Students will understand that eggshells are porous by:        
        A. Examining various dyed eggshells
        B. Telling their similarities and differences 
        C. Examining shells from boiled and raw dyed eggs
        D. Explaining why color may be on the inside or outside
II. Students will understand the value of porosity of eggshells by:
        A. Discussing prior knowledge of "coverings" on various 
           objects, animals, and people
        B. Explaining the need for "covers" on objects, animals,
           and people
        C. Discussing the necessity of holes in eggshells
 
Apparatus Needed:

Several empty dyed eggshells (on outside only)
Several empty dyed eggshells (on inside only)
Boiled dyed and undyed eggs - 1 per child
Raw dyed eggs - 1 per child
Food coloring (red, yellow, green, blue)
Vinegar
Large beaker, water
Hotplate
5 small beakers
Copper wire - cut into 6 inch strips
Paper plates

(For Science Table Display On "Coverings")

Vegetables - carrot, radish, potato
Fruits - peach, grapes, banana
Canned goods, packaged goods
Glass and plastic bottled liquids
Animals - furry, plastic, vinyl
Seashells, starfish

Recommended Strategy:

1.  Have students view objects on science table.  Discuss the types of 
    "covers" on the objects and their usefulness.  Relate and compare 
    to the covering on an egg.
2.  View and discuss a variety of colored empty eggshells (some dyed 
    on the inside only, others only on the outside).
3.  Carefully peel dyed eggshells from a boiled and then a raw 
    egg!!!  Examine, compare, and contrast the two shells.
4.  Explain why some shells seem to have allowed more dye to seep
    through (size of dye molecule, size of "holes" in eggshells).
5.  Explain need for holes in eggshells (to allow embryo to breathe).
6.  Have students explain and demonstrate techniques in dying eggs and 
    eggshells. (OPTIONAL)