Thinking Like a Scientist

Thinking Like a Scientist Important facts about experimenting and the scientific method.

The Steps of the Scientific Method • State the problem or question • Research your problem – collect information. • Develop a hypothesis. • Test your hypothesis. • Record and Analyze your data. • State your conclusions. • Replicate Work

The Scientific Method is really just a process of logical thinking. Each experiment must meet certain criteria in order for it to stand up to the scientific method. If it doesn’t, then the experiment is not valid.

Step OneThe Question or Problem to be solved. • This is the most important part of scientific problem solving. You must pick a question that actually asks a question that can be tested and measured through the scientific method!

For instance, the question “Is Pink Pretty?” is not a question that you can answer through the scientific method. The question must be one that requires you not to ask opinions, but to scientifically test and measure the answer to the question.

Let’s look at some more questions and decide if they are good Scientific Questions. Ok? 1. Does my brother like peanuts or peanut butter better? Good or Bad

BAD!!!! In Fact, HORRIBLE!! • Not only does no one care at all, but it’s not a question that can be tested, measured and retested! • Here’s an important point, by the way, each experiment must be repeated at least • THREE TIMES!!!!!!!!!

How many times?

3 At least three and sometimes more. AND actually TEN or MORE is better!

Let’s look at some more questions and decide if they are good science questions or bad. 2. Does water boil faster with or without salt added? Good or Bad

Good – we can test & measure this one.

Does color affect the absorption rate of sunlight? Good Or Bad

Good! Again, this is a problem that you can establish a procedure, test and then retest.

Step TwoResearch the problem or question. The research doesn’t have to be long, just some basic preliminary information about your topic. For instance, if you were doing a question related to gravity, you would want to find out what gravity is and why it’s important.

Step ThreeDevelop a hypothesis A hypothesis is simply your best guess as to what the answer to your problem is. For instance, if your question was Does hot water or cold water freeze faster? Your hypothesis will either be………

If I freeze cold and hot water then hot water will freeze faster than cold water. Or If I freeze cold and hot water then cold water will freeze faster than hot water. YOUR HYPOTHESIS DOES NOT NEED TO BE CORRECT!!!!

A hypothesis must …. • 1. BE TESTABLE • 2. BE MEASURABLE: avoid words like “better” or “the best”. These are not able to be measured quantitatively. • 3. SHOW A COMPARISON between the experimental and control groups

A HYPOTHESIS is a best guess, not a correct guess. It’s ok if you were wrong. That’s part of the scientific method! Some of the best projects have had an incorrect hypothesis. The main idea is to use the scientific method to solve a problem.

Another example, if you will… Question: Do bean seeds sprout more quickly than corn seeds?

Hypothesis: If bean seeds and corn seeds are planted, then corn seeds will sprout more quickly than bean seeds. Or If bean seeds and corn seeds are planted, then…………

Let’s Practice

Controls and Variables Variables – A changeable factor in an experiment. You should only test one variable at a time. Control group – The standard used for comparison. The control group does not contain the independent variable. It is the “normal” one.

CONSTANTS- anything that must be kept the same for the experiment to be fair or valid. ANYTHING THAT IS NOT THE INDEPENDENT VARIABLE!!!!!

There are two types of variables: INDEPENDENT VARIABLE and the DEPENDENT VARIABLE You should only have one INDEPENDENT VARIABLE in any experiment.

It’s easiest to remember it this way. What you change, control, or adjust is always the independent variable. Let’s look at an example…

Let’s return to the problem earlier of • Does hot water or cold water freeze faster? • In this question, what you change or adjust is the hot or cold water. That means that using hot or cold water is your independent variable. The water freezing time is dependent upon whether the water is hot or cold. Therefore, the dependent variable in this problem is the rate at which the water freezes.

Remember, what you change is the (“I” change) independent variable, whatever you measure or the outcome is the dependent variable. • Let’s look again at the corn and bean seed question and pull out the two types of variables.

The problem: Do bean seeds or corn seeds sprout more quickly? • In this problem the rate (or how quickly) at which the seed sprouts depends on if the seed is a bean seed or a corn seed. Therefore, the dependent variable is the rate at which the seed sprouts. The independent variable (what you control or change) is the type of seed used, corn or bean. • Make sense? Well, let’s try one example together.

Problem: Is coke or sprite more acidic? • Hypothesis: If coke and sprite are tested then coke will be more acidic than sprite. • Variables: Try now to figure this part out and then click to see if you are correct.

The independent variable (what you control) is the type of soda or liquid tested. • The dependent variable is the acidity (or how much acid) of the coke or sprite. • The amount of acidity depends on whether it is coke or sprite.

If all else fails, then try this approach. • “I Choose” the “Independent Variable”. Notice the I in I Choose and the I in Independent Variable. Maybe this will help you remember which is which.

Now, the constants are easy. These are the things within the experiment that you keep the same throughout each test. • For example, let’ return to the problem of does a corn seed sprout faster than a bean seed?

The only thing that is allowed to change is the type of seed: Corn or bean. • Everything else must remain constant (or the same). Would it be fair to soak the bean seed for 2 hours before testing how quickly it grows and the corn seed only an hour? NO!

Would it be fair to wrap the bean seed in a paper towel and leave the corn seed on the table? NO! • You see, in order for the scientific method to work, everything except the independent variable must be exactly the same. EXACTLY! That is the Scientific Method!

Now, try to think of all of the constants that you would have to consider if you were doing the problem of • Does hot or cold water freeze faster?

After you have decided what your question is and how to test it, you should write a procedure for how you will run your test.

Now, you are ready to begin your procedure. Your procedure is extremely important because science requires that if your project is valid, anyone in the world should be able to follow your procedure and end up with the same results 100% of the time! That’s right! 100%!

Therefore, your procedure should be a step by step (listed 1, 2, 3, 4, etc). • Be as detailed as possible and don’t leave a single thing out. Your teacher will help you set up your procedure.

Step FourTest Your Hypothesis • Ok, now your problem is chosen, you’ve researched your problem, developed a hypothesis and written your procedure. What’s next? You guessed it, it’s finally time to actually do the experiment!

Follow your procedure to a T. If you mess up, start over. Take pictures as you go as data and proof of your work. Keep a careful record and maybe keep a journal of the experience.

Step FiveRecord and Study Data • While doing the experiment, you must create some type of chart to keep track of what happened in your experiment during each of your three tests.

Next, study your charts (data) to see if the experiment turned out the way you thought it would (your hypothesis).

Step SixDraw a Conclusion • Finally, it’s time to draw some conclusions. What did you find out? Did the data support your hypothesis or not? • Example: Let’s use the corn seed and bean seed experiment. If the corn seed did indeed sprout first I would write a conclusion stating…

The data collected supported my hypothesis. The corn seed sprouted faster than the bean seed, so I do think there is a relationship between the type of seed and sprouting time.

Any extra conclusions that were drawn during the experiment can also be listed under your conclusion.

Thinking Like a Scientist