Mirror Image|Definition & Meaning


A Mirror Image is the reflected view of an object on the surface of a mirror in a reverse direction concerning the actual object. This phenomenon is related to the light that reflects the image and the type of mirrors used.

Introduction to Mirror Image 

A Mirror Image is an inversed reflection of any object and is perpendicular to the mirror’s surface in such a manner that the reflection seems near identical. We can understand this concept by the easiest example; when you look at yourself in the mirror your right hand appears to be your left and vice versa.

Basic definition of mirror image

Figure 1 – Mirror Image of a Triangle

Detailed Explanation

When a light ray falls on the surface of the mirror, the silver particles on the mirror get excited due to the photons that are present and those they are absorbing. These particles become unstable, so to regain stability, the surface emits some of its photons which results in the reflection of any object which can be seen with the naked eye. 

When a ray of light from a certain source falls on the surface of a mirror, it creates a virtual image within the reflecting surface. This image will be the mirror image which will be perpendicular to the surface. Note that the reflection of an image will always be dependent on the type of mirror in use. 

Let us understand this concept; a man is standing in front of a mirror with his right hand stretched out; the reflection that he sees in the mirror is of himself, but in the reflection, his left hand is stretched out instead of his right hand.

As absurd as this may feel for that man, the reflection he sees has been inverted along the x-axis. This type of inversion gives us a 3D mirror image. The plane upon which this image is being reflected is of the x, y, and z planes. The inversion gives us -x, y, and z as a result, which are the points of coordinates of the object.  

Similarly, if we place a piece of paper in front of the mirror with some text written on it, we will not be able to read the text from the reflection because the image will be inverted horizontally, so the text will also be inverted. This shows that the image you see in the mirrors is identical but opposite. We can use this concept in both 2D and 3D.

Difference Between Mirror and Water Image

As discussed above, a mirror image is the inverted reflection of an object when it is perpendicular to the surface of the mirror.

A Water Image is the reflection of any object in water is called a water image. Let us take an example of a girl who is looking at her reflection of herself in the pond. She notices a reflection of herself in the water at such an angle that it seems that her reflection is standing on the water.

The significant difference between a mirror image and a water image is its symmetrical order. To identify whether a reflection is a mirror image or a water image, keep the following concept in mind. When a reflection is inverted horizontally or along the x-axis, it will be a mirror image. Whereas, if the reflection is inverted vertically or concerning the y-axis, then it will be considered a water image.

Uses of Mirror Image

Mirror images serve an essential purpose when it comes to real-life examples. Some of its uses are:

  1. We use Mirror writing, which is the inverted version of a text, on ambulances. The purpose of doing so is to lets the drivers read the label through their rear and front mirrors so that they can give way to the ambulance without being distracted. This method is used to reduce traffic hazards.
  2. Movie theatres use a Rear Window Captioning System for people who have difficulty hearing or for deaf people. This text helps them read the screen’s captions while enjoying the movie.

Illustrating the Concept of Mirror Images

Mirror imaging is a very interesting concept in geometry, and it has found its way into chemistry and physics too. Let us take an example to understand these concepts.

A mathematical figure

Figure 2 – Image of a number

This is the original image, and when we place this text in front of a mirror, the reflection will be invented horizontally.

Mirror image of a number

Figure 3 – Mirror Image of the number

This shows how the image has not shifted from its original place but has only been inverted. When this image is placed in the mirror, we will get our original image back as a result.

To understand the concepts fully, we will take a look at the following image:

An irregular object

Figure 4 – Image of an object

This image shows a block that is placed in such a way that it looks toward the right, and when we will convert this image into its mirror image (concerning the horizontal axis), the resulting image will look like this:

Mirror image of an irregular object

Figure 5 – Mirror Image of the object

This image shows the inversion that has taken place.

Some Examples of Mirror and Water Images

Example 1

Eliza has the coordinates of an object that she wants a mirror image of. Help her find the inverted image’s coordinates.

\[ (2, 3, 5) \]


When we convert any object into its mirror image, we alter its x-axis as the inversion takes place horizontally. So for an object which lies in the x,y, and z planes, we will change the sign of the point of coordinate representing x. So the final coordinates of the inverted object will be;

\[ (-2, 3, 5) \]

Example 2

Octavia is confused about how a mirror image differs from a water image. Explain the difference by using the following image:

A smiley face

Figure 6 – A smiley face with a tilted cap


When an image is inverted horizontally, it is known as a mirror image. In such a case, we are dealing with the x-axis, and all sorts of changes are made in the coordinate points of x. So the mirror image will be:

Mirror image of a smiley face

Figure 7 – Mirror Image of Example 2

When an image is inverted vertically, then it is called the water image. In such a case, we are dealing with the y-axis and making changes in the coordinate points of y. The water image is:

Water image of a smiley face

Figure 8 – Water Image of Example 2

Images/mathematical drawings are created with GeoGebra.

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