UCSB Science Line
 Does an egg float? Question Date: 2018-01-10 Answer 1: Yes, but only if its old and not good to eat! Fresh eggs, or good to eat eggs, will not float. This is because egg shells have very very tiny holes in them, and over time air outside the egg can go through these holes and into the inside of the egg. New eggs have hardly any air in them (just egg white and egg yolk), which is why they don't float! Answer 2: Egg will sink or float in the water, depending the age and conditions of the egg. Usually the fresh egg will sink into the bottom of cold water. But if the egg ages, the egg could float in water. The truth is that even though the egg has a shell, it is porous which means air can go inside or outside the egg. On the other hand, as time goes on, the slow decay inside the egg will turn the egg white and yolk into gas, which could escape through the porous shell. The water inside the egg could also evaporate over time. In another word, if the egg ages, it will slowly lose its weight because of the slow decay and water evaporation. But the buoyancy from the eggshell itself stays pretty much the same over time, it is not surprising the egg will float eventually if the weight lose is too much such that the buoyancy could totally counter the weight (floating). Best, Answer 3: A fresh egg does not float. It will sink to the bottom of a bowl of water (the water needs to be deep enough to submerge the egg). An egg that floats has gone bad and should not be eaten =). Answer 4: Depends on how much gas there is in the egg. Maybe you should put an egg into water and let us know! Answer 5:A simple answer to this is no, but that assumes that you have a new egg and are placing it into fresh water. In that case, the egg would not float because it is more dense than water. However, an old egg could have a lower density than fresh water (because some of the material inside the egg is able to pass out through the shell), and a new egg could have a lower density than non-pure water (e.g. sea water). Whether or not an object will float in a fluid (not to be too confusing, but a fluid is any substance which can flow, not strictly a liquid) essentially depends on whether the weight of fluid displaced by the object is greater than the weight of the object itself. A detailed description with eggs and water can be found in this earlier question on ScienceLine. If you want to go even further, you can consider putting your egg into other fluids. An easy example is air. (While air is a gas, it is also a fluid.) Since eggs do not bob around in the air like helium-filled balloons, we can conclude that eggs are more dense than air. On the other hand, mercury, which is a metal that is liquid at room temperature, has a density nearly 14 times that of water, and both new and old eggs would float in it. Answer 6:This question has a really fun answer because eggs float â€“ sometimes! When an egg is fresh then it will sink in a glass of water but when it is rotten it will float. How could this be? It turns out that the shell of an egg slowly allows air to sneak inside, the same way that a balloon slowly lets air leave even when the end is tied. Overtime, more and more air will enter the egg making it more buoyant (able to float). When this much air has entered the egg, it is no longer good to eat. The air that spoils your egg is the same air that causes the egg to float. You can test this at home! Go get a few eggs and place them in a cup of water. If they sink then they are still fresh, if they float, you can probably throw them out. Thank you for your question! Answer 7:If you submerge an egg in water, the egg will displace an amount of water equal to the volume of the egg. This is similar to when you get into a bathtub; the water level in the tub will rise because your body displaces the water in the tub. If you could collect only the water that is displaced by the egg and weigh this amount of water, it will give you what is called the buoyant force, which is the upward force exerted by the water on the egg. This principle was discovered by the ancient Greek mathematician and scientist Archimedes and is called Archimedesâ€™ principle. If the egg is heavier than the equivalent amount of water that it displaces, then it will sink because the force of gravity is stronger than the buoyant force. On the other hand, if the egg is lighter than the amount of displaced water, then it will float. Therefore, to decide if something will float we need to look at its density and compare it to water. Density is the mass (amount of stuff) compared to its volume (the size of the stuff). An egg has a density that is slightly larger than pure water, so it will sink, because it will be heavier than an equal volume of water. However, you can increase the density of water by adding salt to the water. The density of salt water is greater than pure water because there is more mass (due to the salt) in the same volume. So if you add enough salt to the water then the egg will float. You may notice this if you ever swim in a salt lake or in the sea. You will find that you float a lot easier in salt water than in a fresh water lake. Click Here to return to the search form.