Dispersion System – Papers, Definitions, Types, Formulas, and Examples

Dispersion System – What is a dispersion system and what is a dispersion? Well, on this occasion we will review paper material on dispersion systems including formulas and types as well as examples and types of solutions in dispersion systems.

Dispersion System

Definition of Dispersion System

dispersion system if in simple terms it can be interpreted as a solution or mixture of two different substances nor is it the same. The dispersion system is characterized by the presence of a solute and a solvent.

For example, three types of objects, namely sand, sugar and milk are each put in a container a container filled with water, then stirred in a separate container, then we will get 3 systems dispersion. Sand, sugar and milk are called the dispersed phase. While water is called the dispersing mediumand.

Definition of Dispersion

Is lost is the event of the decomposition of white light (polychromatic) into its components due to refraction. The color components formed are red, orange, yellow, green, blue, indigo, and purple.

Dispersion can also occur because there is a difference in deviation for each wavelength, which is caused by the difference in the speed of each wave as it passes through the refracting medium. Figure 1. shows the dispersion of white light through a prism.

white light by prism

Refraction of Light on a Prism

Prism is a clear (transparent) object made of glass that is limited by two surface areas that form a certain angle that serves to break up (as a refractor) the rays that hit it.

This surface is called the refracting plane, and the angle formed by the two refracting planes is called the refracting angle (β). Light that passes through the prism will undergo two times of refraction, namely when it enters the prism and leaves the prism.

If the original incident ray and the final refracted ray are extended, then the two will intersect at a point and form an angle called the angle of deviation.

Thus, the angle of deviation (δ) is the angle formed by the elongation of the first incident ray with the ray leaving the refractive or reflected plane. Figure 2. shows the angle of deviation of the refracting prism.

deviation angle

Physics material:

A rainbow is an example of the dispersion of light by raindrops. The raindrops reflect the sunlight towards us so that it breaks down into a rainbow

In quadrilateral ABCE there is a relationship:

+ ABC = 180Hi

In triangle ABC there is a relationship:

r1 + me2 +∠ABC = 180Hi

until the relationship is obtained:

+ ABC = r1 + me2 +∠ABC

b = r1 + me2 …………………………………………………… (1)with:

= angle of refraction of prism

I2 = angle of incidence on the surface 2

r1 = angle of refraction on the surface 1

There is a triangle ACD, ADC + CAD + ACD = 180Hi with CAD = i1 – r1 and ACD = r2 – I2until the relationship occurs:

ADC + (i1 – r1) + (r2 – I2) = 180HiADC = 180Hi + (r1 + me2) – (I1 + r2)

So, the angle of deviation ( ) is:

d = 180Hi – ADC

d = 180Hi – [180o + (r1 + i2) – (i1 + r2)]

d = (i1 + r2) – (r1 + me2)

Diket = p1 + me2 (equation (1), then the angle of deviation that occurs in the prism is:

d = (i1 + r2) – B 2)


= angle of deviation

I1 = angle comes first

r2 = second refractive angle

= angle of refraction

Figure 3. Graph of the angle of deviation of the angle of incidence on the prism.

At the minimum angle of deviation (δ = 0) if the first incident angle (i1) is equal to the second angle of refraction (r2).

Mathematically it can be written the condition for the occurrence of the minimum deviation (δm) is i1 = r2 and r1 = me2so that equation (2) can be rewritten in the form:

dm = 2i1 – b

I1 = (d+b) / 2 .,……………………….. (3)

In addition, the minimum deviation can also occur if r1 = me2then from equation (1) we get:

b = r1 + r1 = 2r1

r1 = 1/2 b ……………………………………………………………… (4)

When connected with Snell’s Law, we get:

n1.here1 = n2.sin r1

(my sin1/my sin1) = (n2/n1)

Come in first1 from equation (3) and r1 from equation (4) to:


If n1 = air, then n1 = 1, so the above equation becomes:

dm = (n2 n1) b………………………………………….. (7)


n1 = medium refractive index

n2 = refractive index of prism

= angle of refraction (peak) of the prism

dm = minimum deviation angle

Types and Examples of Solutions in Dispersion Systems

The types and examples of dispersion systems include:

1. Coarse dispersion

Coarse dispersion/suspension can occur if the diameter of the dispersed phase has a size above 100 nanometers. This system is initially cloudy but in a few moments the boundary between the dispersed phase and the dispersion medium appears immediately due to precipitation.

We can separate the dispersed phase from the medium by filtering.

Examples of coarse dispersion are the dispersion of sand in water, coffee water, river water, a mixture of oil and water, a mixture of wheat flour and water, and so on.

2. Fine dispersion

Fine dispersion is also known as molecular dispersion or true solution. Fine dispersion will be formed when the diameter of the dispersed phase is below 1 nanometer, the system is homogeneous and the solution looks clear.

However, fine dispersion does not produce precipitation so that if we filter the dispersed phase it cannot be separated from the dispersing medium.

Examples of fine dispersions include dispersion of sugar in water, spirtus, NaCl solution in water, vinegar solution, air (a mixture of oxygen and other gases), gasoline, and others.

3. Colloidal dispersion

Colloidal dispersions are also known as colloid solutions. Colloidal dispersion will occur if the diameter of the dispersed phase is between 1 nanometer to 100 nanometer. Colloidal dispersion properties lie between the suspension and the solution.

At first glance, a colloidal dispersion will look like a homogeneous solution. However, if observed under an ultra microscope, we can still distinguish between the dispersed phase and the dispersing medium.

This system is characterized by the condition that the solution is always cloudy but no precipitation occurs so that the filtering of the dispersed phase cannot be carried out. Examples of colloidal dispersions are the dispersion of milk in water, coconut milk, cooked gelatin, detergent, butter, jam, and others.

Thus our discussion of the dispersion system, Hopefully useful..

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