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 Outcomes: 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. Materials: 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 Modeling: 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. Differentiation: 504 modifications ET and MA. Student and teacher modeling will help to guide all students to reach expected outcomes. Guided Practice: http://www.science6.org/pdf/classroom/egg_float.pdf 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 experiment. 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) Reflection: 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. 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: Eggs don’t float. Adding mass (salt) to the water will increase its density. Objects with less density than water (or a solution) will float. o Hypothesis: Students record their hypothesis. o Procedures: Remove egg from solution. Completely dissolve a tablespoon of salt into the water. Carefully put the egg back into the solution. (observe) Repeat until the egg floats. 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: Students state whether their hypothesis was proved or not proved. Students discuss any problems that may have arisen. Students write a sentence to discuss another experiment that this process leads them to want to try. Applications: Would you rather be shipwrecked in the middle of a Great Lake (fresh water) or the ocean? Additional: 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 Water Float? ounces of tap water, a pound of salt and a teaspoon. Fresh no I tried to float the egg in the fresh water and found 1 tsp no that it sank. 2 tsp no The egg was placed 3 tsp no back into the water and I observed that it didn’t 4 tsp no 5 tsp no 6 tsp no 7 tsp no 8 tsp yes I removed the egg and dissolved a teaspoon of salt into the water. float. until I continued following the same procedure the egg floated after adding the eighth 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. This 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?