Welcome to CS

In everyday life, we can often work at multiple levels of abstraction when thinking about a topic or talking about it. We might refer to a particular thing as a “car”. That is sufficient to communicate a lot of important information - that it probably has four wheels, that it is used for transportation, etc… But as we describe a problem we are having with the car, we might need to refer to its parts - say its “engine”. A “car” is just a collection of parts that work together. And the “engine” itself is an abstraction - the engine is made up of a collection of parts and we could get even more detailed by talking about those parts.

In computer science, we often work with similar stacks of abstractions. We build high-level abstractions to describe collections of lower-level data more easily. Images are a great example of this.

Depending on what we are doing with the image, we will need to work with different levels of abstraction. We can draw the image without talking about the grid of pixels. To crop the image, we would need to change the size of its pixel grid, but we would not need to worry about colors. If we want to make the image a little brighter, we will have to talk about the image in terms of the colors of its pixels.