Science Buddies: "Ask an Expert"

Hi,
I am doing a project I found on your website: "Fighting the Flu: How the Immune System Uses its Memory" for my science fair project. My teacher wants me to list the dependent variable, independent variable, constants, and control group or control. Because this is not a true experiment, but a model of the immune system, I am having trouble figuring out what these would be.
I think the dependent variable would be the pathogen (or amount of iron filings on the magnetic tape) and the independent variable would be the antibodies (or the magnetic tape). The constants would be the amount of salt and iron filings in the glass jar. I am not sure what the control would be and I am not sure my thoughts are correct.

Thanks for your help,
Emma Sinelli

Hi Emma,
Very interesting project idea! Like you said, this project is a model of the immune system. To get ideas on how to tweak your project to get a independent variable, I would suggest you take a look at the Make it Your own Tab under your project idea and take one of those ideas into consideration. You can use the ideas into your project and test it with different variables to get different independent variables.

Hope that helped. Good Luck and feel free to ask if you have any questions.
nikhita8

Hi there,

That is a really cool project idea! If you haven't seen this already, Science Buddies has a great page that explains how to identify the independent and dependent variables in your experiments: https://www.sciencebuddies.org/science- ... evariables. The independent variable is what you are changing in your experiment, and the dependent variable is what you are measuring/observing. In the case of this project, you are absolutely correct that the number of antibodies are the independent variable, since you are testing one antibody versus three antibodies. The dependent variable is what you are measuring, which is the amount of iron fillings on the magnetic tape (which basically represents the amount of pathogen that is being "recognized" by the immune system), so you are also correct about that! In terms of controls, it depends on what you want to look at. For example, you can put in plastic wraps WITHOUT the magnetic squares into the jar as a negative control--you would expect no "pathogens" to be bound by the plastic wrap because there is a lack of "antibodies" (the magnetic squares), and this will show that pathogen recognition is specific to the antibodies.

Hope that helped! Let us know if you have anymore questions.

Connie