Egg Float Lesson (A Density and Science Method Experiment)

Instructor: _______________
Subject: Science Grade 6
Time Frame: 40 minutes
Date: _______________
Egg Float (A Density Experiment)
Essential Question:
Would you rather be shipwrecked in the middle of a Great Lake (fresh water) or the
ocean? (Explain)
Objective (s) Numbers:
1.01, 1.02, 1.04, 1.05, 1.06, 1.07, 1.08
Identify and create questions and hypotheses that can be answered through scientific
investigations. *Develop appropriate experimental procedures for: • Given questions. • Student
generated questions. *Analyze evidence to explain observations, make inferences and
predictions. *Prepare models and/or computer simulations to: • Test hypotheses. • Evaluate
how data fit. *Use oral and written language to: • Communicate findings. • Defend conclusions
of scientific investigations.
graduated cylinders, water
bowls and tablespoons
eggs (1 per group)
container of salt (non-iodized - aka Kosher Salt)
Anticipatory Set:
Today we will practice application of the Science Method to a question. Our focus will
be on the procedures step of the method and we will be trying to learn and examine the
concept of procedural repetition.
During the Lesson
Presentation of Information:
Integration of Other Subjects:
Writing (Restating questions in declarative format)
Integration of Reading:
Integration of Technology:
Reading (prereading skills, vocabulary, dramatic presentation)
Reading for information and interpretation.
Computer, Projector, PowerPoint, Internet
Discuss the Procedures Step of the Science Method of Inquiry.
Emphasize the importance of carefully following directions so that the experiments are
perfect repetitions of another.
504 modifications ET and MA. Student and teacher modeling will help to guide all
students to reach expected outcomes.
Guided Practice:
After the Lesson
Independent Practice
Students will follow procedures to discover how many tablespoons of salt are needed to
create a solution with a density that is great enough to allow an egg to float. Students
will identify the independent variable, dependent variables and constants in the
Advanced Learners may want to examine the paper - Egg Float to see how an
abstract is turned into a report.
Closure / Assessment:
Would you rather be shipwrecked in the middle of a Great Lake (fresh water) or the
ocean? (Explain)
Integration with School-wide Focus: Improve Reading and Writing performance
Egg Float Experiment •
Materials: o graduated cylinders, water o bowls and tablespoons o eggs (1 per group) o container of salt (non‐iodized ‐ aka Kosher Salt) Preparation: o While I provide the eggs, I usually ask the students to bring the salt. o 2 containers should be enough for one class. Introduction: o Review the Science Method. o Discuss the Procedures Step of the Science Method of Inquiry. ƒ Emphasize the importance of carefully following directions so that the experiments are perfect repetitions of another. Lesson: o Question: How much salt will be needed to increase the density of the water to a point at which the egg will have a lower density and float? o Observations / Inferences: ƒ Eggs don’t float. ƒ Adding mass (salt) to the water will increase its density. ƒ Objects with less density than water (or a solution) will float. o Hypothesis: Students record their hypothesis. o Procedures: ƒ Remove egg from solution. ƒ Completely dissolve a tablespoon of salt into the water. ƒ Carefully put the egg back into the solution. (observe) ƒ Repeat until the egg floats. ƒ Identify the following: • What was the independent variable in this experiment? • What were the dependent variables in this experiment? • List 3 constants that were a part of this experiment. o Analyze Data: Students record the number of tablespoons of salt that were used to make the egg float. o Conclusions: ƒ Students state whether their hypothesis was proved or not proved. ƒ Students discuss any problems that may have arisen. ƒ Students write a sentence to discuss another experiment that this process leads them to want to try. Applications: ƒ Would you rather be shipwrecked in the middle of a Great Lake (fresh water) or the ocean? Additional: ƒ Students may want to read and examine the science method as applied in the paper, “Egg Float Report” Norman Mitchell
By Norman Mitchell
Norman Mitchell
As a child, I always had trouble floating in a swimming pool but was
able to float easily in the ocean.
Knowing that the ocean is salt water and
the pool is fresh water, I realized that something about saltwater makes it
easier to float.
As a 5 t h grade teacher, it was my job to teach about density
and buoyancy. I learned that salt water had a greater density and that
explained why I had better buoyancy in the ocean!
Now my curiosity kicked
in and I began to wonder how much salt is needed to cause different objects
to float.
I think it will take 15 – 20 teaspoons of salt to raise the density of the
fresh water enough to allow the egg to float.
I tested my hypothesis using
the following procedures.
First I got a fresh egg, a large glass jar, 24
ounces of tap water, a pound of salt and a teaspoon.
I tried to float the egg in the fresh water and found
1 tsp
that it sank.
2 tsp
The egg was placed
3 tsp
back into the water and I observed that it didn’t
4 tsp
5 tsp
6 tsp
7 tsp
8 tsp
I removed the egg and dissolved a
teaspoon of salt into the water.
I continued following the same procedure
teaspoon of salt. You can review my data by looking
at the chart on the right.
Norman Mitchell
One problem that I found was that the water became cloudy and it was
hard to see the egg.
iodized salt.
I discovered that I used iodized salt instead of non-
It turns out that the iodine in the salt causes the water to
cloud. When this experiment is repeated, non-iodized salt should be used to
avoid clouding of the water.
My hypothesis was not proven since it took about half as much salt to
float the egg as I had hypothesized.
This experiment showed me that as the
density of the water is increased, heavier objects could be floated.
conclusion leads me to think that ocean vessels can be more greatly loaded
than those that transport goods on rivers or lakes. Also, I now wonder about
the relationship between the mass of the egg and the mass of the salt added
to the water.
I would like to measure each mass to see if there is a
mathematical connection.
If there is a connection, would using another
substance (such as sugar) with an equal mass to the egg allow it to float?