Our planet is made up of four basic elements: water, air, earth, and fire.
More than 70% of our planet is water. All living beings on Earth depend on water to survive, as they either consume it to live or live within it.
Thousands of species of living beings call water bodies their habitat and home. Beings on land require water to stay hydrated, wash, grow food, and multiple other things. Since water is such an essential liquid, humans have extensively studied it.
Water has many properties and is tasteless and odorless. Water does not possess a shape of its own but borrows the shape of its container.
Water boils at 212 F (100 C) and freezes at 32 F (0 C). Water is formed from two hydrogen atoms and one oxygen atom and its chemical formula is H2O. Another property of this universal solvent is its density.
Using all this information about the abundantly available liquid, humans have found multiple ways to use the liquid and improve their lifestyles. One of the many uses of the vast blue water bodies worldwide is transportation.
Water had been one of the earliest modes of long-distance travel. To achieve this task, humans built boats and ships.
To build a boat, humans first understood what material to use and how to build them to make them float on water.
Like boats and the materials used to build a boat, many other objects float on water and humans learned about why, how, and what those objects were over several thousands of years.
In this article, we have listed different types of objects that float on water and have explained how and why they float instead of sinking to help students learn.
Science Behind Floating
The world is a fascinating place for anyone who looks into all it has to offer. Every aspect of the world has a science and reason behind it.
From an apple dropping to the ground from its tree to the seven-colored rainbow we see on a sunny, rainy day, everything has science behind it.
The apple, or every other thing for that matter, falls to the ground because of Earth's pull on all objects in its atmosphere called gravity.
We can find a rainbow in the sky on days when it rains and shines simultaneously, by a phenomenon where the sun's rays are scattered by the raindrops, emitting the seven colors in its spectrum.
Another natural phenomenon is an object floating on the water without sinking to its depths.
Examples of such objects are wood, ice cubes, boats, balloons, leaves, and paper. Like every other process in the world, there is a science behind why an object floats on water.
When an object is placed on the water surface, it pushes aside some water to make space for its entrance. This process is called displacement.
Along with the process of displacement, we observe two forces that act on an object when dropped into water. A downward force called gravity pulls the object under and an upward force called buoyancy pushes it above the surface.
The force of gravity on a body is measured by its weight. On the other hand, the force of buoyancy is equal to the weight of the water displaced by the object.
If an object manages to displace water equaling its own weight, then the force of buoyancy will equal the object's gravity, so the object floats. And if the buoyancy experienced is less than the gravitational pull, the object will sink.
The amount of water an object displaces upon contact with water depends on its density. Density is the concept of how closely or loosely the molecules in an object are packed.
The molecules are very loosely packed in gases and moderately packed in liquids, while the molecules are compactly squished together in solids. Density is a scientific measure of mass per volume.
In the case of floating, if a density of an object is less than the density of water, that will make the object float. If the density of water is less than that of the object's, it sinks.
Things like ice cubes, oil drops, logs of wood, and paper float on water because they are less dense than water. Hollow objects like balloons, balls, a plastic container, and glass bottles also float because they are filled with air, which is less dense than water.
Though big ships and boats are made of heavy highly-dense metals, their vast base surface area creates more buoyancy and their hollow surface filled with air makes them less dense than water.
Science Behind Sinking
Most actions in the world have an opposite to them. The contradiction to moving is staying still, to talking is keeping quiet, and inhaling is exhaling.
Similarly, the opposite of an object floating on a liquid is the object sinking into said liquid. We have already discussed how an object floats on water, so let us see how sinking works and the examples of objects that sink in water.
When the buoyancy created by an object upon touching the water surface is less than the gravitation pulling it down, the object sinks. If the density of an object is more than the density of water, it sinks.
Solids are generally more densely packed than liquids and gases and water is no exception. Hence, most non-hollow solid objects sink in water.
Some of the basic examples of objects that sink in water are rocks, coins, marbles, and most objects made of metals like paperclips and keys. Any packed solid material will most likely sink in water.
If your phone is accidentally dropped into the bathtub, it will sink to the bottom. So will a bar of soap, a full bottle of shampoo, and multiple other slightly heavy objects.
Examples
Every object in this world has its own physical properties. One such property is the object's density.
The density of an object determines its interaction with other objects. For example, the density of an object compared with the density of water will determine if the object will float or sink. Let's take a look at the objects that are less dense than water, which allows them to float.
On hot summer days, you will notice that ice cubes float at the surface of your glass of water. This is because the solid form of water, ice, is less dense than the liquid itself.
When water freezes, water molecules scatter apart to accommodate the solid form structure, making ice less dense. Most oils are liquids that are less dense than water, which means they float on the surface of the water.
Wood is another example of an object that floats on water. Most types of wood are less dense than water, making them the perfect materials to make a boat.
Another important thing that floats on water is a ship. While a ship is an incredibly heavy object, it still manages to float on water.
This is possible because a ship has a wide base surface area. So, when a ship or boat is placed on the water surface, it displaces more water than other objects, so the buoyancy acting on it also increases, making it float.
Another factor that makes a boat or a ship float is the lack of solid substance filling it.
The ship is built hollow with only air filling it. The shape of a ship also affects its ability to float.
We have all built paper boats in our childhood and set them to sail in puddles created by rain. A paper boat is a light object and paper is less dense than water, so the object floats. Other less dense and light objects that float on water are feathers and leaves.
Objects that are filled with empty space and air also float on water. Balloons, balls, empty barrels, empty bottles, empty plastic containers, floaties, and cylinders are all filled with air.
Hence, when dropped in water, they float on the surface. Some of the materials used to make these objects may have a higher density than water, but because they are full of air, they do not sink but float. It takes a significant amount of weight and force to trap air underwater.
Many less dense fruits and vegetables like apples, oranges, lemons, zucchini, and leafy vegetables float on water, while some heavy vegetables like avocadoes and potatoes sink. Some vegetables and fruits can both float and sink, depending on their individual size and weight.
Other examples of objects that float on water are rubber materials, wax objects, thermocol, dry sponges, plastics, and life jackets. A sponge or a piece of paper initially will float on water, but the longer it stays in the water, the more water it absorbs.
After some time, these objects sink into the water.
Another interesting case is, an egg floats only in seawater or saltwater. The reason behind this is that saltwater is denser than freshwater and the density of an egg is more than that of freshwater but less than that of salt water.
Fun Facts About Objects That Float
A lot of science is involved in determining whether an object floats or sinks in water. Factors like density, weight, gravitational pull, buoyancy, and shape determine whether an object stays afloat or sinks to the bottom. Let's take a look at some fun facts about objects that float on water and how these factors affect the process.
Liquids with a density higher than water will accommodate all the objects that float on water and some more. In contrast, objects that float in water might sink in liquids like vegetable oil, alcohol, or kerosene.
The shape of the object also plays a role in deciding if it floats or sinks.
The more outer surface space touching the water, the better, because the buoyancy increases with surface area. The size of an object might not matter much though, because a huge ship floats on water while a small pebble can't.
Many experiments can be conducted at home to understand this concept better. All you'll need is a tub of water and all the things you are curious to test.
You can test if your plastic comb, fork, craft scissors, and all other day-to-day things float or sink. You can also further this test by wrapping these things in bubble wrap or placing them on wooden planks and then checking if they stay afloat. Bubble wrap acts like a life jacket does for humans.
There are no limits to your learning. We might even find more and more interesting floating objects in the future.
Unser Planet besteht aus vier Grundelementen: Wasser, Luft, Erde und Feuer.
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Bachelor of Science specializing in Botany, Master of Science specializing in Clinical Research and Regulatory Affairs
Sridevi ToletyBachelor of Science specializing in Botany, Master of Science specializing in Clinical Research and Regulatory Affairs
With a Master's degree in clinical research from Manipal University and a PG Diploma in journalism from Bharatiya Vidya Bhavan, Sridevi has cultivated her passion for writing across various domains. She has authored a wide range of articles, blogs, travelogues, creative content, and short stories that have been published in leading magazines, newspapers, and websites. Sridevi is fluent in four languages and enjoys spending her spare time with loved ones. Her hobbies include reading, traveling, cooking, painting, and listening to music.
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Nishtha is an experienced SEO writer and editor, with a passion for writing and self-expression. She is currently pursuing an undergraduate major in Literature and Communication and a minor in Political Science from the University of Delhi. Nishtha has completed a certificate master course in English from the British Council and has been appointed as the editor for the bi-monthly magazine of the University of Delhi.
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