Science at home! Fun homemade experiments for the little ones. Let's learn about Buoyancy and Density !!
Before starting the fun we have to know the theory so let's study:
What is Density?
Whether an object floats or sinks in a liquid depends on the relationship between the densities of the object and the liquid. The density of a substance is obtained by dividing its mass by its volume. The volume is the space it occupies and the mass is easily measured with a weight or a scale. If we divide the mass between the volume density is obtained.
What is the Buoyancy?
Buoyancy is the ability of a body to hold itself within a fluid. A simple way to explain it is that for an object to float it is necessary that the push up is greater than the weight and that depending on the density of the object and the fluid will float more or less.
Now if the fun begins, we go with the experiments:
Experiment of the egg floating in salt water
If you put an egg in water it will sink irremediably to the bottom, but if you add a sufficient amount of salt you will get it to float. Discover why and learn about density and buoyancy with this simple and fun experiment.
Materials:
- A raw egg
- A glass.
- Salt.
- One teaspoon
Process:
- Pour water into a glass.
- Put an egg, carefully, in the water. It will sink.
- Add teaspoon salt to teaspoon and stir carefully not to break the egg.
- After a few teaspoons of salt the egg will float. Got it!
Because it happens?
The egg sinks in the water because its density is greater than that of water. A volume of the egg substance has a greater mass than the same volume of the substance water. By adding a sufficient amount of salt we get a mixture whose density is greater than that of the egg, and as a consequence, the egg floats.
When an object enters a liquid displaces or dislodges the water necessary to make room, since two things can not be in the same place at the same time. We noticed it because the level of liquid increases in the glass. The volume of liquid dislodged has mass. If the mass of the object is larger than the mass of the dislodged liquid, the object sinks. For an object to float, it must be able to dislodge a volume of water whose mass equals the mass of the object.
Fleet experiment or sinks with fruits and vegetables!
Will a lemon float? Will a mango sink? Make predictions and be surprised with this simple and fun experiment with which children, in addition to having a great time, will discover why some things float and others sink.
Materials:
- Fruits and vegetables.
- A bowl with water, if it is transparent better.
Process:
- With each fruit, children formulate their hypothesis.
- Next, check if your predictions are true by introducing each fruit in the water.
- What factors influence a fruit float or sink? Will it be your mass? Will it be your volume?
- The peeled fruit has less mass, that is, on a scale it will weigh less than without peeling. Then the mass alone is not a determining factor. Volume alone does not seem important either because a small potato does not float. So, what happens?
What is happening?
Whether an object floats or sinks in water depends on its density. Objects that have a density greater than that of water sink into it. Let's see why: when we introduce an object into a glass of water, the level increases. This is because the object occupies a place, it has volume and to enter the water it must dislodge it, since two things can not be in the same place at the same time. The volume of evicted water has mass. Remember that all mass is attracted to the center of the Earth due to gravity and that the greater the mass, the greater the force of attraction. If the mass of the object is greater than the mass of the volume of water dislodged, the gravitational force is greater on the object than on the dislodged water and as a consequence, the object sinks.


Great, another home made experiment!
I am seeing this type of experiments getting popular, and the kid was certainly very happy to do something different like this. Fun way to learn without doubt.