Science Buddies: "Ask an Expert"

This question refers to this project:
ttps://www.sciencebuddies.org/science-fair-pro ... ml#summary

I am helping my daughter with her science fair project which involves creating false-color images of x-ray data from the Chandra X-ray telescope (she is looking at Eta Carinae.) She is having trouble, as am I, grasping what the variables are. Her hypothesis is along the lines of: Because Eta Carinae is a very hot double star system, I expect it's center to be very hot, surrounded by a cooler cloud of gas. Colorizing x-ray images will reveal a hot center surrounded by a cooler gaseous cloud. Is the dependent variable the colorization process (Red, Green, Blue), the independent variable the black and white x-ray images and the control variable Nasa's own colorized image of Eta Car?

Hi - I am sharing some information from one of our scientists in response to your questions about your daughter's project.

It sounds like your daughter has done a great job of completing her background research and has a clear understanding of the features she should see in an image of Eta Carinae. This is critical because the whole project is about using the process of false coloring X-ray images to identify features. Let’s talk about how that relates to the independent and dependent variables. If you look at this page about variables (https://www.sciencebuddies.org/science- ... /variables) you can see that the dependent variable is the thing you measure or evaluate. So, what is your daughter measuring or evaluating? She’s evaluating whether or not the final image she creates clearly shows the known features of Eta Carinae.

Now that we know what the dependent variable is, let’s think about the independent variable. You can see from the page on variables that the dependent variable is the thing a scientist changes. In the strictest sense, it is a single thing, but often in the real world, we have to be a bit more flexible. This is definitely true in a data science project like this one where the experimentation (gathering the data) is already done (the team that runs Chandra did it by capturing the X-rays). In a data science project it is better to think of the independent variable as the process you take to analyze the data. This means your daughter needs to outline her process and identify what she will systematically change in the process. I see two things she could systematically change. Which she chooses is up to her. Option 1: She could systematically change her process for tuning the individual low (red)/ medium (green) /high (blue) X-ray images using values she identifies beforehand. In this option, she would then combine the red/green/blue images in the same way each time, then evaluate the results (the dependent variable). Option 2: She could make systematically change how she combines the red/green/blue images. In this option she’d tune the red/green/blue images in a the same way (meaning she creates a checklist that will tell her when the images are tuned well and follow the same checklist for the low, medium and high X-ray images), then vary how she combines the three images. She could try combining them equally, or by emphasizing one more than another. Then, she evaluates the results (the dependent variable).
Did you notice that I used the language “in the same way” in both of the options? The things that she does “in the same way” are the controlled variables. Based on which option she chooses she’ll need to make a list of those.

Once your daughter has made her choice about her independent variable, she can re-write her hypothesis and prediction to reflect those choices. She can learn more about writing a hypothesis from this resource: https://www.sciencebuddies.org/science- ... hypothesis

I hope this information helps. Let us know how the project goes!

Amy
Science Buddies