How Computers Work · Inside a Computer · Lesson 1 of 5

The Parts Inside

Open the case and meet each part, from the motherboard to the fans.

Opening the case

You use your computer every day. Now let's look inside. Every laptop and desktop has the same main parts. In a desktop they are easy to see, so we will start there.

The case is the box that holds everything. Take the side panel off and the first thing you notice is a big flat board.

That board is the motherboard. It is the main circuit board that every other part plugs into. Think of it as the streets of a small town. It carries power and messages between all the buildings.

Near the top of the motherboard sits the CPU, short for central processing unit. It is the chip that follows the instructions in your apps. It is the brain of the computer. You usually can't see it, because a cooler sits on top. A cooler is a block of metal with a fan that pulls heat away from the chip.

Next to the CPU are a few long, thin sticks. These are RAM, short for random access memory. RAM holds whatever you are working on right now, like an open document or a web page. It is fast, but it only keeps things while the power is on.

Your phone has all of these too. They are just squeezed onto one tiny board.

On the practice computer, tap each part inside the case to learn what it does. Then finish the quick match at the end.

Power, pictures and cooling

The CPU and RAM do the thinking. A few more parts keep your files, draw the picture and keep everything running.

Storage is where your files and apps live when the computer is off. Most new computers use an SSD, a solid state drive. It stores data on memory chips with no moving parts, so it is fast and quiet. A common kind, called M.2, is a small card about the size of a stick of gum. It plugs flat onto the motherboard. Older computers often use a hard drive, which stores data on a spinning disk.

The GPU, or graphics processing unit, draws everything you see on the screen. Some computers have a big graphics card with its own fans. That helps with games and video editing. Many laptops build a smaller GPU into the CPU chip instead.

The power supply, or PSU, is a metal box that takes power from the wall. It turns it into the gentler power the parts need. A laptop has a charger and a battery that do the same job.

Finally, there are fans. Working parts get warm, and too much heat makes them slow down. Fans pull cool air in and push warm air out. If your computer gets loud when you do something heavy, that is the fans working harder.

Here is a simple way to remember it. RAM is for now. Storage is for later.