Check Out 50+ Interesting Things That Float

The concepts of floating and sinking are some of the prime foundations of science.

The way some things float in both air and water while some do not is quite a puzzling phenomenon for budding children. While the common way to classify objects is commonly by their weight, there are several other factors that play a role in the floating and sinking of different objects.

Different objects float in both air and water in their own ways, enough to jumble up our understanding. Household objects, for example, candles, a toy boat, apples, empty bottles, and eggshells, are seen to be floating in the water, but rocks or metals sink immediately.

But what really is floating? Floating is the phenomenon where objects tend to, completely or partially, stay on the surface of the water.

To elaborate, a human being swimming in a pool is equally considered as floating as is a balloon in the air. Thus, unlike popular beliefs, floating is much more about the density of the object than it is about its weight, materials constituting it, trapped air, or even the kind of liquid it's in.

Keep reading to find out how density contributes to floating and sinking, and also find some interesting ideas and hands-on activities to experiment with these claims yourselves. Also, read many intriguing facts about why do things float and examples of objects that float in water.

Science Behind The Things That Float

Besides its density, the buoyancy of an object determines its ability to float. Displacement explains why and how something floats in a different way while some other objects are found sinking.

All the objects that we see around us are all composed of molecules. Molecules in water are loosely placed, thereby giving the water its fluidity, while on the other hand, the molecules that fill up solids are very tightly packed, leading to the concreteness of solid objects like a rock.

It is because of this reason that oil and other such liquids tend to float on the surface of more dense liquids like water, and solid objects like a rock or a metal sink down at the bottom.

The idea of buoyancy may be a novel one for kids, completely foreign in their vocabulary, but can be easily explained like the force of gravity, but in reverse.

The buoyant force is the upward thrust that pushes the lesser dense objects to the surface of the liquid and causes them to float. For instance, a boat floats in water only when the pressure that it creates downward is lesser than the water's buoyant force upwards. In just the reverse case, the boat would happen to sink.

Similarly, when an object is hollow and contains trapped air, it will float on the surface of the water. For example, a rubber tube, duck toy, plastic bottles, and the like will never sink owing to the trapped air that brings down the object's density.

Things That Float On Water

Things float in water only when they are less dense than water, are made of certain hydrophobic materials, and also when they are capable of displacement of water.

Leaves, wooden logs, paper, large ships, a hollow rock, fiberglass, plastic balls, styrofoam, oranges and lemons, bubble wrap, sponges, and oil will all experience floating when placed on water; while a pin, coins, and marbles would immediately sink - suggested by their dense molecular composition.

Objects made from materials like polyethylene, plasticine, and polypropylene also typically float on water.

Often a science book will explain the striking difference between a huge ship floating and the sinking of an iron pin. Here comes the concept of displacement.

When an iron pin is released in water, it sinks due to its higher density than that of water. While on the other hand, a ship engineered to float will demonstrate an anomaly. It is indeed more dense than water and supposed to sink.

When a ship is suspended in water, we learn that it participates in a phenomenon called displacement. In other words, the ship occupies enough space by displacing or removing a sufficient amount of water to maintain its buoyancy.

Similar observations can be found when the water level rises in a bathtub once a person jumps in.

Things That Float In Air

Similar to water, an object floats in the air when it is less heavy than air, causes enough displacement of air to make room for its surface, and maintains buoyancy.

Paper, kites, gas-filled balloons, hot air balloons, dust, birds, flies, airplanes, satellites, soap bubbles, feathers, dried leaves will all float in the air.

When talking about floating, children readily associate the concept to dense liquids and other solutions while the same is applicable and perfectly correct for objects in the air.

It might come as a surprise to kids, but the air is dense, and its value is one. Items that are lesser than one will float in the air. For instance, a balloon filled with helium gas floats in the air, gradually moving upwards, defying gravity.

An airplane floats in the air by utilizing buoyancy created by the low pressure on the upper side and high pressure on the downward side of the wings. A hot air balloon is made of materials that are denser than air and could sink in no time, but they float when filled with gases lighter than air.

What are the experiments that can be done?

Children can experiment with household items and see which objects float and which sink for themselves. These practical activities will bring out a greater enthusiasm in children and help them learn and retain information better than a science book.

Take a plastic bottle and suspend it in a bucket full of water. Gradually fill it with water to one-fourth, then half, and eventually fill it completely to the brim.

Note down your predictions and mark when in the experiment did the bottle float in water and when it sank. This is a standard activity to explain density to a child.

Another way to experiment with different densities is to take a pencil, a cork, a paperclip, oil, cotton ball, and stones and suspend them in water to find which predictions were correct about the densities being less than water.

To test buoyancy in water, take an orange and notice if it sinks or remains afloat in water. If the orange is initially heavier than water, you might notice an increased water level in the container as soon as the orange is placed.

If it remains afloat, you get to see buoyancy acting up. Now peel the orange, depriving off of its less dense covering. You might notice the orange sink with the force of gravity having failed to displace enough water.

Activities with a paper kite will let you test floating in the air. Get yourself a paper kite on a windy day to perform this activity.

Similar to an airplane, the low pressure above the kite and high pressure beneath will launch the object to flight.

The forward tug is known as thrust, which you can observe with the forward motion caused by the tension on the string, known as drag. To keep the kite steadily moving with the wind, you need to keep the four sides of the kite balanced, but it need not be performed just to test floating.

Another fun experiment that will let you understand how airplanes work - the ping pong ball experiment. Cut out the top of a plastic bottle and create a hole in the cork for a straw with adult help. Fixate the straw into the cork and make sure it is tight and well secured.

Suspend the ping pong ball in the bottle and blow from the other end. You will see how the dense ball levitates when you apply wind pressure. Otherwise, it sinks.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for checking out 50+ interesting things that float then why not take a look at why do boats float or how to float in water.