Floating Egg Experiment
Will an egg float in fresh or salt water?
Will an egg float in fresh or salt water? The Floating Egg Experiment is an easy hands-on investigation that can be done in your own kitchen! I have used this lab before as a class demonstration, group lab investigation, and with my own kids at home. There are several science terms and concepts that can be taught in this experiment including density, solutions, mixtures, saturation, concentration, mass, and the list goes on. Scroll to the bottom to download your own Floating Egg Experiment Lab Sheet!
*Don’t miss out on the Salt Water Density Lab featuring a free observation lab sheet too! And be sure to check out all of our FREE Science Resources including our Labs & Experiments!
As a Christian Book and Amazon affiliate, we may earn commissions from qualifying purchases. Thank you for your support. As always, we only recommend items that we truly feel will benefit your homeschooling experience. We appreciate it.
Floating Egg Experiment Introduction
Before conducting the experiment, there are a few things you should cover with your students to create a meaningful learning experience. First, spend time talking about the terms below. We discuss the meaning of salinity and a homogeneous mixture amongst other concepts. Since this investigation is demonstrating the difference in density between salt water (oceans) and fresh water (rivers, lakes, ice), it works well with our Water Distribution Unit.
Important Terms and Facts
– Salinity describes the amount of salt dissolved in water. Saline water is water with salt dissolved in it.
– A homogeneous mixture is a type of mixture where a solute (salt) is dissolved into a solvent (water). This type of homogeneous mixture is called a solution.
– Density is the amount of mass in volume. Volume is the amount of space something takes up.
– Buoyancy is a force on an object making that object rise or move forward.
Floating Egg Experiment Lab Sheets
Write Hypothesis
Once you have introduced the key terms in the Floating Egg Experiment, make sure the students are given the following facts and the FREE FLOATING EGG EXPERIMENT LAB SHEETS.
- Water has a density of 1 g/mL (g/cm3).
- Objects will float in water if their density is less than 1 g/mL.
- Lastly, objects will sink in water if their density is greater than 1 g/mL.
After giving your students this information, guide them to write a hypothesis for the posing question, “Will an egg float in salt or fresh water?”
For example, their hypothesis could read like this:
If I add 1 TBSP of salt to every ½ cup of fresh water, a raw egg _____________________________ float.
Students will plug in the words, “will” or “will not,” in the blank of the hypothesis.
Identify Variables
Identifying variables in an experiment is something that takes most students practice. It is a good idea to continuously review the following terms. Check out our Scientific Method unit to get more practice.
Manipulated Variable– variable that is different in the experiment. It is the thing that is manipulated. *In this case, the manipulated variable is the amount of salt added to the water.
Responding Variable– variable that is being tested. It responds to the manipulated variable. *Hence, if the egg floats or not.
Controlled Variable– variable(s) in the experiment that do not change or remain the same. *In this lab, the glasses and raw egg are the controlled variables.
Review the experiment before conducting...
For you teachers, it is always advisable to try an experiment out first to ensure that it works the way it is supposed to. There is nothing worse than demonstrating in front of a group of students for an experiment to flop! It has happened to the best of us… yes, it has happened to me! Watch this video I found on YouTube to get a step by step of the experiment. It is pretty easy to demonstrate.
I have used this experiment for years with the exception of the salt water with the fresh water on top. That aspect of the experiment was new to me. So, I too tried this at home before showing it to my students. *I wonder if it will work with glasses that aren’t quite so narrow at the bottom? Let’s see…
Gather Materials
The materials list is likely to all be found within your kitchen. I love experiments that do not require a tricky supply list. So, gather 3 raw eggs, water, salt, a spoon, 3 clear glasses, and a measuring cup and tablespoon come in handy.
Fresh Water first and then Salt Water
I always start demonstrating the egg sinking in the fresh water first. Next, you will show how adding salt to the fresh water will change its density. Thus, the egg will now float in the denser salt water. In the Egg Floating Experiment, I use 1 tablespoon of salt per 1/2 cup of water. This enables the students to measure more precisely. Some kids need the restrictions.
*On their lab sheets, students will draw and record observations and make conclusions.
Extended Learning...
This aspect of the Floating Egg Experiment is a new for me. I never did this in years past, but what a great addition. You can choose to demonstrate this last glass or the students can continue to follow the procedures on their lab sheet. In the end, take the time to talk about the science behind this experiment. This is where the science comes all together!
What's the Science behind it?
It’s very important that before, during, and after an experiment that you are explaining the science behind the experiment. If you skip this step, then the lab becomes merely a fun hands-on activity with no real science connections. The experiments are meant to help the students get past the surface and begin to soak in the abstract and unseen science behind it.
Glass #1– The egg sunk to the bottom in glass #1 because the egg is more dense than the water. Hence, the egg has more mass in its volume than the water does.
Glass #2– The egg floats in salt water because the salt water is more dense than the egg. This means that the salt water has more mass in its volume than the egg does. The salt adds mass to the volume of the water creating a more dense liquid.
Glass #3– When the egg is put in the cup, the glass is only half full with a mixture of salt and water. This causes the egg to float in the salt water instead of sinking. When plain water is added to the salt water, the egg remains in the middle of the glass because of density. The plain water is the least dense, then the egg, and the most dense is the salt water at the bottom of the glass.
*When the floating eggs are pushed into the salt water, the eggs float right back up to the top of the salt water. This is due to buoyancy. The force of the salt water causes the egg to rise back up.
check out these other free resources!
John 4:14 – But whosoever drinketh of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life.
