Why are some kids sad? What makes the wind blow? How do birds fly? [1] Our world is full of curious phenomena. [2] To find answers or solve problems, we can use a process, which was first acknowledged by the scientist and philosopher Ibn al-Haytham, in the 11th century. [3] Also known as Alhazen, he is considered to be the father of optics - and the scientific method. [4]

There are six steps to it: [P] 1. Observe and Ask Questions [1] 2. Research [2] 3. Formulate a Hypothesis [3] 4. Test your hypothesis [4] 5. Conclude [5] 6. Share Results [6] The goal of the scientific method is find out the truth. Let's try. [7]

Step 1: Observe and Question [1f] Observation helps us formulate challenging questions that you will be able to test. [2] A good question converts the natural sense of wonder into a focused line of investigation. [3] When is the best time to drive to school? [4] Which food is my dog’s favorite? [5] If you observe that women smile more often than men, you might ask: why do women smile more often? [6]

Step 2: Research [1f] Find out if other people have asked the same or similar questions. [2] If you research online, use search terms like [3.1] “study ...”, [3.2] “research ...” [3.3] or “meta-analysis ...” [3.4] - which is a summary of research for a specific topic. [3.5] Read as much about your particular subject to see what you can find out about. [4] Research happiness based on gender or [5] study the science of smiling in different cultural contexts. [6]

Step 3: Formulate a Hypothesis [1f] A hypothesis is a theory that you can test to see if your prediction is [2.2] right [2,3[ or wrong. [2.4] From your observation, you have noticed that woman smile more often and that people who are smiling seem to be happy. [3] From your research you know that there are different types of smiles, [4.1] shy, [4.2] genuine [4.3] and false. [4.4] In one paper you read that baby girls smile more often than baby boys. [5] Here is a hypothesis: Women smile more than men because they are happier than men. [6]

Step 4: Test Your Hypothesis [1f] When you test your hypothesis, you want to make sure to do this in a fair way and that the conditions are constant. [2] For this hypothesis, we can design a test where an interviewer talks with a set of men and women [3.3] for 5 minutes each, [3.4] counts how many times they smile, [3.5] and then asks each one to rate their level of happiness. [4.1] To get a good sample of the population, we invite [P] 300 women [4.2] and 300 men. [4.3] Seems like a good test, right? [5] But wait, what if the interviewer is a woman, and men tend to smile more at women? [6.2] Or vice versa? [6.4] Or what if the topic discussed is one that interest women more than men? [7] And what if people aren’t reliable reporters of their actual level of happiness? [8.2] So clearly, we would need to be much more careful. [8.3]

Step 5: Analyze and Conclude [1f] Let’s assume that you designed a very careful experiment, controlling for as many variables as possible. [2] Now you can analyze the data to see if your hypothesis is correct, or incorrect. [3] Depending on your findings, [4.1] you may want to change your hypothesis [4.2] or change the design of your testing. [4.3] Perhaps you have discovered an even more interesting question. [5] This stage of the scientific method can be repeated as many times as necessary until you find just the right hypothesis and test method to find accurate results. [6]

Step 6: Share the Results [1f] When you are satisfied that you have proven or disproven something important, [2.1] report your results. [2.2] In science, it is important to detail your methods so that your peers can review your work - which is a critical step to getting published. [3] If your results are solid, your experiment can be repeated by other scientists. Such reproducibility is a sign of good scientific work. [4] But failed results can also be interesting - an incorrect prediction could prove to be important and should always be reported. [5] To make sure you get it completely right, here are 3 more things you can check before you publish: [6]

A) Any scientific theory is falsifiable [1f] Real scientists know that there is no such thing as a scientific proof. In other words, you can never prove your theory to be 100% right. [2] All you can do is find A LOT of supporting evidence that it could be correct. [3] Here is one example: [P] Say that someone says “hamsters CAN fly,”. We cannot prove that this as false. [4] Yes, we have never seen a hamster fly, [5] but we can’t test all possible conditions or look in all possible places on the planet to know that ALL hamsters NEVER fly. [6] Maybe a space hamster does? [7] So while we can often prove that a phenomenon exists, it’s much harder to prove the nonexistence of something. [8.2] If your theory can't possibly be proven wrong, then it's not falsifiable and hence, not scientific. [8.4]

B) Correlation is not Causation [1f] When you analyze your results, [2.1] it is important to separate between two possible reasons: [2.2] correlation [2.3] or causation. [2.4] Let's you hear that towns that have more churches also have more bars. [3] Could it be that religion makes people want to drink? [4.1] Or that drinking helps people to find God? [4.2] If you add more facts, [5.2] such as “larger towns have both more bars and more churches,” [5.4] you can see that a larger population is a more likely cause of higher numbers of bars AND churches. [5.5] There is probably a correlation, but no causation. [P] If we compare men with women [6.1] and would conclude that woman smile more [6.2] and are more happy [6.3], then this still doesn’t mean [6.4] that its happiness that makes them smile. [6] Maybe they just eat more chocolate and cookies, which makes them both: happy and smile a lot. [7]

C) Avoid Selective Windowing [1f] When you publish you got to show ALL relevant facts. [2] Colgate once ran a advertising campaign claiming that “80% of dentists recommend Colgate”. [3] What they didn't tell us [P] is that when they asked dentists to select their preferred toothpaste, Colgate was just one of many other brands they also also recommended. [4] Colgate was later sued [5.1] and forced to take down their misleading ads. [5.2] The purpose of science is always to find out the truth and nothing but the truth. [6] To use science to mislead us is wrong and terrible business practice. [7]

Lets do a last example together. [P] I have two coins. One is bigger. [1.1] Why?[1.2f] The small coin says 1 Cent, the bigger one says 5. [2.2] Aha![2.3f] Small coins are worth less money. [3.1] Bigger coins are worth more money. [3.3][3.4f]. I pull some more coins from my pocket. 2 more Pennies, [4.1] 1 more Nickel, [4.2] and a Quarter Dollar, [4.3] which is 25 Cents. [4.4f] Great, my hypothesis seems true. But wait, is the quarter worth more because it is bigger? So is that a correlation or a causation? Hmmmm… [5.1] My sample size is pretty small. [5.3] I don’t think I am ready to report my results. [5.4][5.5f][6.1f] Can you help out? [P] Please apply the Scientific Method to study you local currency. [7] Maybe you have a hypothesis that we can test until we get solid, repeatable results to report. [8.1] Please publish your findings in the comments below! [8.2]