Emission theory (vision)
Emission theory is a really old idea about how we see things. It's like the idea that a little bit of light comes out of our eyes and helps us see stuff. Imagine you're standing in front of a tree. According to emission theory, your eyes are sending out tiny little things called "visual rays" that go all the way to the tree in front of you. These visual rays bounce off the tree and then come back into your eyes. Your brain then takes all these visual rays and tells you that you're looking at a tree.
Now, scientists know that this isn't actually how we see things. In reality, light comes from the tree and enters our eyes. Our eyes are really good at taking that light and sending it to our brains, which then tell us that we're looking at a tree. But back in the day, people didn't know that, so they thought that it was our eyes that were "shooting out" visual rays.
While these days we know that emission theory isn't right, it was an important idea that helped people understand vision for a long time. Today, we use more advanced and accurate explanations to understand how we see, but it's still cool to look back at the ideas that people used to have about vision.
Now, scientists know that this isn't actually how we see things. In reality, light comes from the tree and enters our eyes. Our eyes are really good at taking that light and sending it to our brains, which then tell us that we're looking at a tree. But back in the day, people didn't know that, so they thought that it was our eyes that were "shooting out" visual rays.
While these days we know that emission theory isn't right, it was an important idea that helped people understand vision for a long time. Today, we use more advanced and accurate explanations to understand how we see, but it's still cool to look back at the ideas that people used to have about vision.