What Is an Algorithm?

Ages 3-5 Simple Explanation

You know how when you get dressed in the morning, you follow steps? First you put on your underwear, then your pants, then your shirt, then your socks, then your shoes. That list of steps is kind of like an algorithm! It's a set of instructions you follow in order.

You know how when you brush your teeth, you always do the same steps? Pick up the toothbrush, put on toothpaste, brush your teeth, spit, rinse. An algorithm is just a fancy word for steps like that, but for a computer instead of a person.

Computers need algorithms because they can't figure things out on their own. They need someone to tell them exactly what to do, step by step. An algorithm is like a recipe that tells the computer every single thing it needs to do.

You use algorithms every day without even knowing it! When you sort your toys by color or follow the steps in a game, you're following an algorithm. It's just a big word for something you already know how to do.

Ages 6-8 More Detail

An algorithm is a set of step-by-step instructions for getting something done. Think of it like a recipe. A recipe for making cookies tells you exactly what ingredients you need and what order to mix them in. An algorithm does the same thing, but usually for a computer.

Here's a simple example of an algorithm: How to make a peanut butter sandwich. Step 1: Get two slices of bread. Step 2: Spread peanut butter on one slice. Step 3: Put the slices together. Step 4: Eat! That's an algorithm. It's a clear set of steps that leads to a result.

Computers use algorithms for everything they do. When you search for something on Google, an algorithm decides which results to show you first. When YouTube suggests a video, an algorithm picked it. When a game figures out if you won or lost, an algorithm calculated that.

What makes algorithms so important is that they help computers do things really fast. A computer can follow an algorithm millions of times per second. That's why your search results pop up almost instantly. The computer is following its algorithm at incredible speed.

You can even write your own algorithms! If you've ever given someone directions to your house, you wrote an algorithm: 'Turn left at the stop sign, go two blocks, turn right, it's the third house on the left.' Step-by-step instructions that lead to a result. That's all an algorithm is.

Ages 9-12 Full Explanation

An algorithm is a precise, step-by-step set of instructions for solving a problem. The word might sound technical, but you encounter algorithms every day. A recipe, driving directions, and the rules for long division are all algorithms. In computer science, algorithms are the recipes that tell computers how to process data and make decisions.

What makes algorithms so powerful in technology is that computers can execute them incredibly fast. When you type a search into Google, an algorithm sorts through billions of web pages and returns the most relevant results in less than a second. When Spotify makes you a playlist, an algorithm analyzes your listening history and compares it to millions of other users to predict what you'll like.

Social media algorithms are especially important to understand because they shape what you see every day. TikTok, Instagram, and YouTube all use algorithms to decide which posts and videos show up in your feed. These algorithms prioritize content that keeps you engaged, which means dramatic, emotional, or controversial content often gets pushed to the top because it gets more clicks and reactions.

Not all algorithms are created equal, and they can have real problems. Because algorithms are written by people and trained on data, they can reflect the biases of their creators or their data. For example, a hiring algorithm trained on past hiring decisions might discriminate against certain groups if those past decisions were biased. An algorithm is only as fair as the data and rules behind it.

There are many different types of algorithms designed for different problems. Sorting algorithms arrange data in order. Search algorithms find specific items in a dataset. Recommendation algorithms suggest content you might like. Encryption algorithms protect your data by scrambling it so only authorized people can read it. Each type has been carefully designed to solve its specific problem as efficiently as possible.

Understanding algorithms gives you a behind-the-scenes look at how the digital world works. When you realize that the videos in your feed weren't chosen randomly but were selected by an algorithm designed to keep you scrolling, you gain power over your own attention. You can ask: is this content really what I want to see, or is it just what the algorithm thinks will keep me watching?