Why does a Laptop get hot?

Thoughts about the energy concept

Let’s talk about energy. But don’t despair, this won’t become too theoretical. I promise. All I want to do is to nudge you into the right direction of thinking about energy as a concept that can explain many things in everyday life. Because that’s all there is to it. Obviously, the last sentence isn’t true, as energy is still something worth researching. But the technicalities are not important, but how we think about it is. So let me give you an example.

You have probly already noticed how electric gadgets get hot sometimes. After a while, my laptop gets too hot to sit on my lap. And then there’s my cat, who adores the warmth radiating from a laptop. So much that this actually happened a couple of years ago.

My cat loved the warmth from the laptop so much that he fell asleep under it.

But what is actually happening with the laptop? Why does it get hot? If we want to answer that question, first we need to answer three smaller questions:

  1. Where does a Laptop get hot?
  2. When does a Laptop get hot?
  3. How do we stop the Laptop from getting hot?

Now, I didn’t come up with these questions but my colleague Julian did. He develops so called curriculum replacement units, which are small units that can be implemented in the physics classroom without much expense and they all revolve around energy as a cross-cutting concept. Isn’t that cool?

He believes that these coherent units, which address and connect different aspects of the energy concept support integrated knowledge about energy which ultimately leads to a better understanding of the concept and easier transfer onto different topics. As energy is one of the most prominent and biggest topics in school and everyday life, this only seems logcal, wouldn’t you say?

What happens when a Laptop is turned on?

Let’s take a look with an infrared camera.

The longer the Laptop is turned on, the warmer it gets.

These infrared cameras (or thermal imaging cameras) detect wavelengths which are longer than those of the visible light and is mostly thermal radiation. Which is why we can visualize heat with an infrared camera.

In the video, we can see clearly which parts of the laptop get hot and which don’t. It’s clearly the part where most of the electrical gadgets sit on the inside of the laptop. So there might be something happening with the electrical energy we need to actually run the laptop.

Obviously, the computer does only get hot when it’s turned on. Besides turning electrical energy into light (like with the laptop screen), there is also thermal energy. Cleaning all parts and making sure they work the best they can is one of the most common tips that you can read on the internet when asking about why the laptop gets hot.

This is because the electrical energy cannot be used as such and therefore transforms into thermal energy. Another word for it is the energy conversion efficiency.

This is only one of 12 units, my colleague develops. I love how the units are all relevant in everyday life and connect different aspects of the energy concept with another. They provide so much more than just calculations about energy transfer or explanations about one energy representation. I really do believe he might contribute to a coherent teaching of energy.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s