The floating egg experiment is a fun and easy way to explore the science of density and buoyancy using just a few simple materials. This hands-on egg science experiment is perfect for elementary students and makes a great science fair project idea or science activity for the classroom.
Floating Egg Experiment for Kids
The floating egg experiment is an engaging way to teach kids about the density of the objects and buoyant force. With just a cup of salt and a large container of water molecules, you can create an exciting science activity and learn about the scientific method.
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Recommended Grade Level: Grades 3-6
Materials:
- 2 tall drinking glasses
- Cups of water (fresh water and salt water)
- 2 uncooked eggs (shelled)
- Tablespoons of salt (about 6 per cup)
- Spoon to stir
- Masking tape and permanent marker for labeling (optional)
Sink or Float Egg Set Up
Watch the Video:
Step 1: Pour plain tap water into the first tall drinking glass and label it as “fresh water.”
Step 2: Carefully place one egg into the cup of tap water and observe what happens. The egg sinks to the bottom.
Step 3: In the second glass, pour the same volume of the water, but this time, add tablespoons of salt one at a time, stirring after each addition. Continue adding enough salt until the salt dissolves completely and forms a saltwater solution’s density higher than the egg’s.
Step 4: Slowly place the second egg into the saltwater solution. Watch as the egg first floats to the top!
The Scientific Method
Using the scientific method helps students think like scientists! Follow these steps:
💡Read more about the scientific method, including hypotheses and variables in science.
- Ask a Question: Why does an egg sink in freshwater but float in salt water?
- Research: Find out about density, buoyancy, and salt concentration.
- Hypothesis: If salt is added to the water, then the egg will float because the density of the solution increases.
- Experiment: Follow the step instructions above to test the hypothesis.
- Variable:
- Independent Variable: Amount of salt added to the water.
- Dependent Variable: Whether the egg sinks or floats.
- Controlled Variables: Amount of water, type of glass, same size egg.
- Observe & Record: Write down how much salt was needed to make the egg float.
- Conclusion: The more salt dissolves in the water, the higher its density, making the egg float.
Floating Egg Experiment Extensions & Variations:
- How much salt? Try adding different amounts of salt and observe at what point the egg begins to float.
- Use different eggs. Does an old egg float faster than a fresh one?
- Test different liquids. Try using liquids like soda water or sugar water.
- Scientific method approach: Record observations and results in a science journal.
Quick Fact: Fresh Eggs vs. Expired Eggs
Did you know that a fresh egg sinks while an expired egg floats? As eggs age, the liquid inside evaporates through the shell, leaving a larger air pocket behind. This increased buoyancy causes older eggs to float in freshwater, making this a simple way to test egg freshness at home!
Discussion Questions:
- Why does the egg float in salt water but not in fresh water?
- What happens if you mix half plain tap water and half saltwater solution?
- Can you make the egg hover in the middle by carefully adjusting the salt concentration?
Egg Science Fair Project Ideas
Yes! The floating egg experiment is a great science fair project because it is easy to set up, follows the scientific method, and allows students to explore and analyze results. Here’s why it works well:
💡Explore more science fair projects here with tips and free printables.
- Simple Setup: Uses common household materials like eggs, salt, and water.
- Encourages Inquiry: Students can ask, “How much salt is needed to make the egg float?”
- Measure and Graph Data – Record the salt needed for different eggs and display the findings in a chart.
- Test More Variables – Compare fresh vs. expired eggs, or use sugar water instead of salt water.
- Real-World Applications – Connect this to real-world examples like why people float more quickly in the ocean than in a pool.
- Use the Scientific Method – Add a background research section and explain concepts like buoyancy, density, and molecules.
Easy Egg Experiments
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