Tag Archives: experiment

Mistakes in Experimental Design and Interpretation

Mistakes in Experimental Design and Interpretation:

Humans are very good at detecting patterns, but rather poor at detecting randomness. We expect random incidents of cancer to be spread homogeneously, when in fact true randomness results in random clusters, not homogeneity. It is a mistake for an experiment to consider a pool of 47,000 possibilities, and then only report on the 7 cases that seem interesting.
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A proper experiment states its hypothesis before gathering evidence and then puts the hypothesis to the test. Remember when you did your seventh grade science fair experiment: you made up a hypothesis first (“Hamsters will get fatter from eating Lucky Charms than Wheaties”) and then did the experiment to confirm or refute the hypothesis. You can’t just make up a hypothesis after the fact to fit the data.

This is an excellent article discussing very common errors in how people use data. We have tendencies that lead us to draw faulty conclusions from data. Given that it is important to understand what common mistakes are made to help us counter the natural tendencies.

Related: Seeing Patterns Where None Exists – Illusions, Optical and Other – Understanding Data – Dangers of Forgetting the Proxy Nature of Data – How to Deal with False Research Findings – descriptive “theory” and normative theory

Home Experiments: Quantum Erasing

Do your own experiment on quantum erasing – Quantum Erasing in the Home (for instructions). From the accompanying article, A Do-It-Yourself Quantum Eraser:

The light patterns that you will see if you conduct the experiment successfully can be accounted for by considering the light to be a classical wave, with no quantum mechanics involved. So in that respect the experiment is a cheat and falls short of fully demonstrating the quantum nature of the effect.

Nevertheless, the individual photons that make up the light wave are indeed doing the full quantum dance with all its weirdness intact, although you could only truly prove that by sending the photons through the apparatus and detecting them one at a time. Such a procedure, unfortunately, remains beyond the average home experimenter.

Related: Science Toys You Can Make With Your Kids – Particles and Waves

Designed Experiments

One-Factor-at-a-Time Versus Designed Experiments by Veronica Czitrom:

The advantages of designed experiments over [One Factor at a Time] OFAT experiments are illustrated using three real engineering OFAT experiments, and showing how in each case a designed experiment would have been better. This topic is important because many scientists and engineers continue to perform OFAT experiments.

I still remember, as a child, asking what my father was going to be teaching the company he was going to consult with for a few days. He said he was going to teach them about using designed factorial experiments. I said, but you explained that to me and I am just a kid? How can you be teaching adults that? Didn’t they learn it in school? The paper provides some examples showing why OFAT experimentation is not as effective as designed multi-factor experiments.

Related: Design of Experiments articles – Statistics for Experimenters (2nd Edition) – Design of Experiments blog posts

Science Toys You Can Make With Your Kids

Simple steam boat

Science Toys You Can Make With Your Kids

Photo: the simplest steam engine you will ever see. It has no valves, no moving parts (in the traditional sense of the phrase), and yet it can propel it’s little boat easily across the largest swimming pool or quiet duck pond.

The site includes many simple projects to create toys and teach scientific principles in a fun way with simple materials. Gonzo Gizmos, is the book the site is based on.

Projects include: the impossible kaleidoscope, a simple rocket engine, building a radio in 10 minutes and building your own solar battery.

This cool site is definitely worth a visit.