Concave vs. Convex

Concave and Convex – these two words are not often used in our day-to-day speech, but they have significant use in Mathematics and Science. Generally, both words are used as an adjective. Concave is used to describe shapes that bend inward like an hourglass, whereas the word Convex defines shapes that curve outward like a soccer ball. 

Most of you might have come across these terms when discussing lenses in eyeglasses, contact lenses, or mirrors. In this article, we will get to know about the difference between these two terms and when to use them along with some examples. 

Difference Between Concave Vs. Convex

As mentioned above “concave” means rounded inward or hollowed outward while convex has the opposite in meaning, curved or rounded outward. Though both words have been used for centuries, a lot of people often mix them up. 

When to Use Concave

Concave is an adjective that is used to describe a surface that curves inwardly or is slimmer in the center than on the edges.  We generally use this word to describe glass surfaces such as lenses of spectacles and other viewing equipment. 

Concave is also used as a noun for a surface curving inward.

Examples of word “Concave” in sentences

  • Side mirrors in vehicles always have a concave surface as they reflect more in small space.
  • Most eyeglasses nowadays have a concave surface inside.
  • These binoculars feature concave lenses.
  • Concave lenses are useful in the treatment of low vision.
  • This advanced viewing equipment is made out of a double concave flint lens.
  • Some of these prisms are combined with concave lenses.

When to Use Convex

Contrary to concave, the word convex describes the surface that is thicker in the middle than on the edges and curves outward. Like concave, You will often notice the use of this word to describe the process associated with reflection, mirrors, and lenses.

Examples of word “Convex” in sentences:

  • The convex shape of ice cream scoop gives perfectly round scoops.
  • The convex shape of the air balloon helps hot air to lift it from the ground surface.
  • The convex bulbs look beautiful on the Christmas tree.
  • The focal length is accurate for a concave mirror while inaccurate for a convex mirror.
  • This convex mirror will reflect the light outward.

How to Remember the Difference Between Two

One easiest trick to remember the difference between two is that remember the meaning of one, another will automatically be remembered. You can remember that concave means curving inward while convex means curving outwards. You can remind the “cave” part of the word concave and then recall the mouth of a cave that curves inward. Thus you can remember that the word concave is used for something that is bent inwardly.  

Both convex and concave words are used to describe a shape, surface, or a line. Though they are majorly used in Science, Mathematics, and relation to mirrors, you might need to use them anytime. Therefore, you should know the difference between them.

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