Okay kiddo, you know how our body has different parts that we can measure like our height, weight, and temperature? Well, our mind is kind of like another part of our body but we can't measure it as easily. When people say "measuring the mind," they're talking about trying to figure out things like how we think, feel, and remember things.
Scientists who study the mind use a lot of different methods to try and measure what's going on in there. One way is to ask people questions. For example, they might ask you how you feel when you see a certain picture or how you remember where you put your toys. These questionnaires can give scientists an idea of what people are thinking and feeling.
Another way to measure the mind is by looking at people's brains. There are special machines that can take pictures of your brain and show which parts are active when you're doing different things. Scientists can use these images to figure out what parts of our brains are responsible for different thoughts and feelings.
There are also some tests that people can take to measure things like intelligence and memory. Have you ever taken a test at school where you had to remember a bunch of things and then write them down later? That's one way to measure memory.
Overall, measuring the mind is a tricky thing because our minds are very complex and everyone thinks and feels differently. But by using all these different methods, scientists can learn a lot about how our minds work and why we think and feel the way we do.