This lesson developed by Reach Out!
Recommended Age Groups: early or later elementary
What can I learn from playing with an egg?
- Eggs come in different sizes.
- Eggshells are porous.
- Eggs roll in a funny and wobbly way.
- Measuring things helps us find out exactly how big or tall something is.
- Eggs may look like they are the same size, but they aren't. We can
measure the vertical and
horizontal lines of eggs
to see just how big they are.
- Eggshells are porous so that air get in and out of
- Many objects roll. Eggs roll and wobble in such a way so that they
don't travel very far and so they stay near the mother hen.
- Eggs have inside them everything that a baby bird needs
to grow to the point of being ready to be hatched and finish growing in
- Because eggs are a funny and oblong shape, they roll and wobble around
in a certain way. If eggs were round, they would probably roll out of
nests or too far away from the mother hen.
- Eggshells have to have little
holes in them so that air can move through and into the egg for the
growing baby bird.
- We can see evidence that there are little holes in an eggshell by
putting it in water and seeing air bubbles. Air can not only get into
the egg, but come out of it, too.
- Making Observations
- Following Directions
- Making Inferences
- Each person or pair needs 3 or 4 eggs.
- 6 inch pieces of string
- A wide mouth glass jar that an egg can fit into
- A ruler
- Warm water
- Waterproof felt pen
- Aluminum pie plate
Each person or pair needs plenty of room to try 3 little
experiments including letting an egg roll away from them.
Procedures and Activity
- What do we know about hen eggs?
We see hen eggs all the time. We buy them at stores, put them in
the fridge, color them at Easter time, cook them in many ways
and eat them, put them in lots of different recipes.
- Eggs are fun to learn about. We are going to do some activites and
experiments to learn more about the properties and characteristics
of the simple hen egg.
Activity #1: Are all eggs the same size?
- When you go to a store, you find eggs in cartons according to size.
You can buy small, medium, large or extra large eggs. Let's measure
eggs to see just how big they are. Eggs that may look like they are the
same size really aren't! One way to check out how big an egg is, is to
measure it vertically and horizontally.
- Let children pick out 3 or 4 eggs that appear to be the same size.
Demonstrate how to use string to measure the egg vertically and
horizontally. Talk about what vertical and horizontal mean (see glossary). Put a ruler down on the table or desktop.
Use a piece of string to go around the middle or horizontal area of
an egg. Put a felt-tip mark on the end of string that matches up with
the beginning of it. Then put the string along the edge of the ruler
and see how long it is. Write down this measurement by Egg 1 on the
- Show them how to measure the egg vertically, mark and measure. Record
the measurement on the handout.
- Have the children do the same thing with their 3 or 4 eggs, keeping
measurements on the handout.
- Share measurements of eggs to see that eggs that appear the same size
really aren't. And look how very different eggs can be size-wise!
- Talk about the scientific process. Our question was, "are all eggs
the same size?" Our experiment was to measure many eggs
vertically and horizontally. We kept track of our measurements on a piece
of paper. We all measured our eggs in the exact same way. What did we
learn? Eggs do not come in the same size—even when they have been
sorted for size!
- Scientists do experiments like this all the time. To test our findings,
someone else can take our eggs and measure them to see if they come up
with the same findings. If you want to, and have the time, let children
swap their handouts and eggs with one another to double check
measurements and findings.
Activity #2: How do eggs roll?
- Have children put some newspaper on the floor or the tabletop
- Put one egg at a time on the paper and push it so it rolls away from you.
Observe how it rolls.
- How would you describe an egg's movement?
- Why do you think eggs roll that way?
- Share that the wobbling means they won't roll too far away, so they
would stay near the mother and in the nest.
Activity #3: Do eggshells have little holes in them?
- Look at the eggs. What do you notice about the shells? Do you think they
have little holes in them?
- Like a scientist, we will do an experiment to see if there are tiny
holes in eggshells.
- Each person or pair needs to fill their jar half full with warm
- Place one egg into the glass jar.
- Carefully observe or watch what happens to the egg. Does it float or
sink to the bottom of the glass?
- What does the egg look like in the water? Do you see little bubbles?
Which part of the egg is giving off bubbles?
- What are the bubbles telling us? There is air inside the egg that can get
outside. How? Air can escape from the inside because there are very tiny
holes in the eggshell. This means the eggshell is porous, or it has
little holes in it, so that air or water can go in or out of the egg.
- Why do you think it is important for the eggshell to be porous? If there
were a baby bird growing in our egg, it would need air. This is how air
would get into the egg.
Activity #4: Where is the air inside of the egg?
- Give each person or pair an aluminum pie pan.
- Demonstrate how to crack open an egg and put the contents inside of it
onto the pie pan.
- Have children crack open and put egg contents onto their pie pans.
- Again, we are going to carefully observe the inside of an egg. What do
we see? Look for the egg white, the yolk, and the air sac.
- Draw some conclusions to see that air goes in and out of an egg because
the eggshell is porous and has little holes in it. The air sac inside of
the egg holds the air. Air has oxygen. If our eggs were fertilized eggs
with chicks growing inside, the babies would need oxygen. Oxygen
would be provided to the baby from the air sac.
- Where is the air sac in an egg? Think about where we saw air bubbles
when we put an egg in a glass of water. That is evidence for where we
think the air sac is inside of the egg.
Closing - Original Question:
What do we know about hen eggs? Ask again:
Are eggs the same size?
What did we learn when we measured eggs?
Look at our findings.
Even eggs that seem to be the same size, aren't!
How do eggs roll?
Think about what we observed when we pushed the eggs so they moved
away from us. How would we describe their motion and action? Why
do we think that eggs roll and wobble so?
Are eggshells porous? (Or, do they have tiny holes in them?)
Go over the experiment when we put eggs into a glass of warm water.
What did we see? What do we think was happening? Is this evidence
that there are, in fact, tiny holes in eggshells?
Where is the air inside of an egg?
Review what we found when we cracked open eggs and examined
what was inside of them.
What is an air sac? Where do we think it is found inside of the egg?
Why do we think that? What evidence do we have to support our hunch
from the experiment when we put an egg into water?
Why would a baby chick need an air sac?
Listen carefully to how children answer the questions at the end of
the lesson. If they are confused, be sure to re-do experiments or at
least talk over what we asked and learned. We want them to understand
- Eggs are not all the same size.
- Eggshells are porous or have little holes in them so air can get
in and out of the egg.
- If we had fertilized eggs, the baby chicks would need air to live
- Air is found inside the egg in an air sac.<
- Eggs wobble when they roll so they won't go far from
a mother hen and they will stay inside of a nest.
Probably the very best way to see if children understood this lesson
is to let them teach it to someone else. Encourage children to take
these experiments to other classes, their girl or boy scout groups
- Have fun with eggs by exploring the different ways we can cook them!
Write recipes and experiment with frying, poaching, steaming, and baking
- Pick out different recipes which include eggs as an ingredient, from
quiche, to cupcakes, to cookies,to casseroles, to meringue on a pie.
Students learn lots from cooking and baking! They learn to plan and to
follow directions. They may learn to use a stove and an oven. You can
also include a study on the nutritional value and cholesterol concerns
- Check out our other egg-related lessons and activities: Egg Drop and Air Pressure, Egg Magic, Eggs Don't Break?, and Egg-Carton Glider.
Careers Related to Lesson Topic
- A hard-shelled thing that birds lay with everything inside
of it needed to produce a baby bird.
Note: The eggs we eat are not fertilized, so they would
not develop into baby chicks.
- The outside hard covering of an egg that protects what
is inside it.
- The line that is like the horizon we see when the sun is rising in the
morning or going down at night. We are measuring the horizontal
line of our eggs when we measure around its middle.
- To use your eyes and very carefully watch something going on. We are
carefully observing what happens when we push eggs and they roll away
from us. We are carefully observing when we put our eggs into
water and look to see what happens.
- When something has little tiny holes in it so that water or air can go
- A line that is perpendicular to the line of the horizonor the
top to bottom of our eggs.
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Last revised 23 Jan 05