Why the sea is blue for children

The first thing to keep in mind to explain to children and adults why the sea is blue is to understand what color is . Colors are actually the result of the way light reflects off objects . In fact, we do not see colors, but light reflected from objects that, upon reaching our eyes, and later on to our brain, our body interprets, creating the image of objects and the world that surrounds us.

However, it must be taken into account that the light that objects reflect is not all the light that reaches them. In reality, bodies absorb a part of that light and reflect another part and, once it is reflected, that will be the light that will reach our eyes and that we will see, giving rise to the colors that we see. In this way, the light that the different objects absorb will be just the color that we will not see, since it will have previously lost it when absorbing the light from this part of the spectrum.

In other words, colors are the light that does reflect off our bodies and that reaches our eyes . Thus, if we see an object of red color, it will be because the object has absorbed the rest of the light of the color spectrum, allowing only the part of light that corresponds to that color to be reflected.

Based on the fact that we already know what color is and how we see it depending on how objects reflect light, we can understand why the sea is blue . This is due to the fact that water absorbs the part of the spectrum of light that corresponds mainly to the part of the red and infrared colors. In this way, the part of the visible light spectrum that is reflected to a greater degree is the one that corresponds to blue , which makes the ocean water look this color when the reflected light reaches our eyes.

In addition, other factors must be taken into account, such as the fact that sea water is not pure water, which makes the tones that it can take are modified by the different elements that are dissolved in it, especially minerals, although pollution can also cause the color of sea water to appear in different tones.

Learn more about this interesting topic in this other AgroCorrn article on Why sea water changes color .

According to what we have just seen, the water absorbs the light corresponding to the red part of the light spectrum, which makes it reflect the most bluish part and, consequently, the light that reaches our eyes reflected in the sea is seen in shades of blue. But, when we see other bodies of water, such as the one we can serve in a glass, it is completely transparent in color. How is it possible?

This is because the part of the light that water absorbs is proportional to the amount of water we have. Thus, when we say that water is transparent , we are not being entirely sincere. The correct thing to do would be to say that in small amounts, water is clear, while in larger amounts, water is blue .

We can observe this phenomenon especially well when we have bodies of water of different sizes in front of us, and it will allow children to understand why sea water is blue and in the glass it is transparent much better.

If we drink a glass of water, it is visible that it is transparent-looking water. However, if we look closely at the water in a bathtub or a swimming pool with a white background, we will see that, although it is timidly, the water begins to take on a slightly bluish color. This becomes much more palpable as we expand the size of the body of water, since the amount of red and infrared light that is absorbed is greater, until we reach sea water, which is the largest body of water that we can. observe and, consequently, also the one that absorbs the most of this part of the spectrum light.