Scientific Method SC.912.N.1.1

What are the steps to the scientific method What are the steps to the scientific method? Yes, write that question down but don’t write this sentence down. Someone raise her or his hand and tell me the first step.

Robert has just moved to South Florida from North Dakota Robert has just moved to South Florida from North Dakota. He has been getting a rash on his body since arrival.

The rash is not very painful or itchy so he would like to figure out what the cause is without seeing a dermatologist. Can he use the scientific method? What would be a good problem statement?

Problem statement: What the heck is causing this rash Problem statement: What the heck is causing this rash? What would be his next step?

Robert thinks to himself: I’ll do a lil’ research on the topic Robert thinks to himself: I’ll do a lil’ research on the topic. Here’s what I came up with. The rash didn’t begin until I arrived in Florida. I have been using a lot of sunblock lately. I take more showers now than I did in ND. I eat more beans now than when in ND. I began using soaps LUSH cosmetics. It’s more humid in Florida. There are more insects in Florida that bite me. I went to a pool party in Wellington. I wore a few shirts without washing them first.

Hmmm, I really think it’s mostly likely something external since the rash appeared quickly so, I’m narrowing it down to 3 things. Here’s what I came up with. Sunblock Designer Soap Clothing dye

Further research has yielded these results. Some sunblock ingredients can cause allergies. Soap and detergents rarely if ever cause rashes. Dirty shirts or dyes within a newly bought shirt can cause a rash. Robert has done some research so now what is his next step?

Robert believes that the heavy dye in the shirts he purchased are most likely the cause of the rash. This is his _____________, which is a proposed explanation for how the independent variable and dependent variable are related.

Robert believes that the heavy dye in the shirts he purchased are most likely the cause of the rash. This is his hypothesis, which is a proposed explanation for how the independent variable and dependent variable are related. Sometimes referred to as an educated guess by people in middle school.

What would be a good hypothesis statement? What are the variables? The dye in the shirts. The rash If I wear a shirt with heavy dye, then I will develop a rash on my skin because the dye irritates my skin. (Easiest method but not what most scientists use).

What would be a more succinct hypothesis statement? Clothing dye is positively associated with skin rashes.

The next step is to design an experiment, which is a controlled procedure carried out to test a hypothesis. Give me some ideas about how Robert could test his hypothesis.

Robert decides to test his hypothesis by purchasing a set of new, undyed, white t-shirts and wearing them for one week. During the experiment, what should Robert be doing?

Robert makes observations and collects data by keeping a log and taking pictures of his back.

After 1 week, Robert looks at his results and analyzes it. The rashes on his skin seem to still be present after 1 week and showed no sign of subsiding. What conclusion do you think he makes?

Robert decides to reject his hypothesis and writes in his notebook “the absence of clothing dye does not appear to have any effect on the presence of skin rashes for me.”

What was the treatment “group” in this experiment? What was the control “group” in this experiment? Even though his hypothesis was rejected, this experiment was not a total waste of time. Why not?

The next day, Robert decides to stop using sunblock for a week, but keeps all of his old shirts. Why?

He did acquire new knowledge from the experiment He did acquire new knowledge from the experiment. He is now fairly confident that the dye is not the problem.

Do you think that Robert continued to use his sunblock during this period? Why? Do you think that he continued to use the designer soap? Why?