Once upon a time there was a girl named Regina. She was a very smart, curious little girl who always asked a lot of questions. She loved talking to people and learning all about the way things work.

Sometimes she would look at the sky and ask, "why is it blue?" or "why do clouds have different shapes?" She would ask about the animals and the plants. She would even ask about other people. She was always interested in learning more about the world.

One day, she saw a movie about a scientist and wanted to know more about what they do.

She saw all the cool experiments and thought, "How do they do all of those awesome things? I wish I could do those too!"

When she went to school the next day, she asked her science teacher, Mr. Stats, about scientists.

Regina asked, "How do scientists do all those cool experiments? How can I be one when I grow up?"

Mr. Stats chuckled. "That's a big question for a kid like you. The answer isn't a simple one. Are you sure you want me to explain it to you?"

"Of course!" Regina exclaimed.

"Alright then," said Mr. Stats. "Well before you understand the cool stuff, you need to understand some of the basics. You need to understand what research is."

"Research?" Regina asked. "What's that?"

"Research is gathering information about a certain topic. Kind of like what you're doing right now. Without research, scientists would not know how to do experiments." Mr. Stats explained.

"So researching is just asking questions and trying to find answers? Are there other ways to do research?"

"There are many ways of doing research. One way is to ask experts or people with knowledge. You're a natural at that. Another way is to read books about the topic. You can even create your own experiment if you want to research something."

"That is so cool! So how do I create an experiment? What kind of things do I need to learn to do that?" Regina asked.

"Well the first thing you have to do is learn what a variable is. If you know what you want to study, you can create an experiment that lets you find out if what you think will happen really does happen." said Mr. Stats

"What is a variable? I think I heard them talking about it in the movie."

"A variable is something that can change. For example, variables can be things like time, amount of sunlight, age, or temperature. There are two types of variables: independent and dependent."

"What do those mean? I've heard the word independent before but I've never heard of an independent variable."

"An independent variable is a variable that you can control or change during the experiment. If you're doing an experiment about whether plants grow better with or without sunlight, you can change the amount of sunlight the plant gets. You can put one plant outside and the cover the other one so that each plant gets a different amount."

"So if you can change the independent variable, is the dependent variable the one that can't change? How does that work?"

"You're a very smart young lady. The dependent variable is the variable that you look at and measure. Instead of changing it, you are trying to see what happens to it when you change the independent variable. In the plant example, the dependent variable is how tall the plant is."

"So if I know what I want to measure and what I want to change, what else do I need to know? Is that all I need to do my experiment?" Asked Regina.

"You're learning a lot today. In order to do an experiment, scientists need to understand two very important things: reliability and validity."

"My mom always tells me that I'm reliable because I always help her out. What are those things? And how do they help me do experiments?" Asked Regina.

"Reliability is basically getting the same results when you do the same experiment multiple times. For example, if you step on the same scale everyday and you always get the same weight, that means the scale is reliable."