Tag Archives: how to think like a scientist

8. How to Think Like a Scientist — Following the Evidence

Nobel Prize-winning physicist and accomplished bongo player Richard Feynman, in the classroom.
Nobel Prize-winning physicist and accomplished bongo player Richard Feynman, in the classroom.

When he was a kid, my buddy Richard was smart enough to be afraid of dragonflies.  They had a wicked bite or sting or whatever.  They were dangerous and scary.  Every kid in his town knew this.  The flying terrors were even nicknamed “darning needles”.  When a dragonfly would buzz by during school recess, kids would scream and scatter away.  The same thing was true in my hometown.  My brother even played baseball with a guy who got bit or stung or whatever by a dragonfly and had to be taken to the hospital.

My friend Richard was afraid but also curious.  He wanted to know how bad these ‘darning needles’ really were.  Was it a bite?  A sting?  How painful?  Deadly?  What were the best tactics to stay safe?

He wasn’t a freakazoid, though.  He wasn’t crazy enough to want to experiment with them personally.  Instead, Richard researched the topic to learn what other scientists had found.

This was the days before Google searches and Wikipedia.  So Richard got a book about dragonflies and read all the facts.  Guess what he found?  Dragonflies don’t bite or sting; they are totally harmless!

So when a dragonfly landed on his foot at the beach that summer, he amazed everyone by casually observing the bug and not flinching.  The other kids were screaming and running away in terror, and Richard just stood there, as cool as an ice cube.  Richard was small for his age and not physically strong, but on that day he was the Big Man on the beach.

Thinking like a scientist, Richard followed the evidence he learned and changed his ideas about dragonflies.  To continue being scared after learning they were harmless would be just silly.

Everyone has ideas they believe to be true.  But good scientists are not afraid to follow the evidence wherever it leads.  It’s okay to experiment on your own, and even try a few times.  But if the evidence clearly contradicts your original position, a good scientist admits he’s wrong, and revises his position.   A bad or lazy scientist ignores evidence or make excuses and just keeps his old views.

It takes courage.  I’m sure that Richard was a little scared when that dragonfly first appeared at the beach.  But he trusted the facts he had learned.  Science is about making accurate predictions.  Accuracy comes from following the evidence.

Talking like a scientist, Richard did 5 important things:

  1. He had a hypothesis – “dragonflies are dangerous”
  2. He researched the topic, learning facts that others have already discovered
  3. He found evidence that falsified his hypothesis
  4. He revised his hypothesis – “dragonflies are dangerous harmless”
  5. He experimented, testing and confirming the new idea

My buddy Richard’s last name is Feynman.  I never met Richard Feynman but I call him a friend because he is one of my heroes.  He grew up to become a Nobel Prize winning physicist and accomplished bongo player. Learn more about him at http://www.feynman.com/

Fun Phineas Feynman Quote

“Nature doesn’t care how smart you are. You can still be wrong.” –Richard P. Feynman

Do-It-Yourself: Build a Solitary Bee House

"Male Mason Bee (Osmia)" - Copyright 2007 by Stavros Markopoulos (Creative Commons).
“Male Mason Bee (Osmia)” – Copyright 2007 by Stavros Markopoulos (Creative Commons).
If you want to welcome some of the world’s great garden-helpers to your backyard, you need to build them a nice place to stay. Everyone thinks of bees as living in bee hives because honeybees do and honeybees are easily the world’s most famous bees.

But of the thousands of bee species, only a few make honey and live in hives. The rest are solitary bees.

Maybe the most popular type of solitary bees to have around are Mason bees. They are popular because they do a super job pollinating fruits, vegetables and flowers. They are also very mild and don’t sting unless they are handled roughly or get trapped underneath clothing.

There are more than a hundred kinds of Mason bees in North America. They work and live alone, although they don’t mind nesting right next door to other bees.

Mason bees build nests in long narrow holes that they find already made in their environment. These holes could be hollow plant stems or holes drilled by woodpeckers and insects in wood. The bees use mud to build chambers in the holes, then lay an egg in each chamber. Before sealing up the chamber, they leave a dab of pollen and nectar in each for the larva to eat when it hatches.

When the young bees have matured enough in the spring, they’ll bust out of their mud chambers and eventually come to the front of the hole to warm up a bit before flying off to begin the entire cycle again.

When the bees do fly off, the first thing they’ll be looking for is a home. You can help by building them a solitary bee house.

Following the easy directions below, and with just a little help from your folks, you can build a solitary bee house over the winter and have it in place by March or April. Be sure to mount it solidly somewhere out of the rain facing South or East since the little bees need some sunlight to get them going when they emerge.

And remember, building the bee house is just the beginning of the fun and your research. You’ll need to see who shows up and moves in. Get pictures if you can. And by all means, take notes and hold onto them so you can build on your store of observational knowledge year over year.

Here are some questions to get you started:

  • How many different kinds of bees use your solitary bee house? Simply knowing the number of different kinds is useful, but if you want to dig in and get very, very specific, there’s help: www.DiscoverLife.org
  • How many of the tubes get sealed off with mud? Does one size (diameter) seem more popular with the bees in your neighborhood. Develop a hypothesis about what size tubes will attract the most bees next year. Test it.
  • What kind of mud do the bees use to seal chambers? During periods of high activity, put out trays of different kinds of mud to see if the bees have a preference. Does putting mud close to the bee house increase the trip rate of bees (say, three trip every minute instead of two trips a minute)? By how much?

How to Build a Solitary Bee House

The bundle of hollow tubes you gather will need to be secured and held together. Some people use duct tape; others use a beautiful wooden container of some sort. For our purposes here, we picked a common (and free!) option we had around the house.
The bundle of hollow tubes you gather will need to be secured and held together. Some people use duct tape; others use a beautiful wooden container of some sort. For our purposes here, we picked a common (and free!) option we had around the house. (Recycling, anyone?)

When it comes to hollow tubes, nothing beats bamboo. If you have it growing in your yard, you are set. If you don't, ask around. Most people who have it will be more than glad to let you cut some of their bamboo. When picking the size you need, consider this: to attract Mason bees, you want to aim for a hole diameter that is big enough to insert a pencil in, but not too much bigger.
When it comes to hollow tubes, nothing beats bamboo. If you have it growing in your yard, you are set. If you don’t, ask around. Most people who have it will be more than glad to let you cut some of their bamboo. When picking the size you need, consider this: to attract Mason bees, you want to aim for a hole diameter that is big enough to insert a pencil in, but not too much bigger.


The good thing about bamboo? It is tough. The bad thing? It is tough. You'll need an adult and the appropriate tools to get what you need from your neighborhood bamboo thicket. Luckily, anyone with bamboo growing in the backyard probably already knows how to cut it.
The good thing about bamboo? It is tough. The bad thing? It is tough. You’ll need an adult and the appropriate tools to get what you need from your neighborhood bamboo thicket. Luckily, anyone with bamboo growing in the backyard probably already knows how to cut it.


Use scissors to trim your drink bottle to a length of at least 6 inches.
Use scissors to trim your drink bottle to a length of at least 6 inches.


While trimming the branches off the bamboo, get as close a cut as you can. This will make it easier when you are sliding the tubes in because there won't be obstructions.
While trimming the branches off the bamboo, get as close a cut as you can. This will make it easier when you are sliding the tubes in because there won’t be obstructions.


Cut lengths of bamboo to the same length you trimmed your bottle. It doesn't have to be perfect.
Cut lengths of bamboo to the same length you trimmed your bottle. It doesn’t have to be perfect.


If one of the tubes you are trimming begins to split, don't worry. It will be unusable, but will provide an opportunity for you to investigate the internal structure of the plant.
If one of the tubes you are trimming begins to split, don’t worry. It will be unusable, but will provide an opportunity for you to investigate the internal structure of the plant.


Pack the tubes into your container as tightly as you can. It may take a little effort to work in the final few.
Pack the tubes into your container as tightly as you can. It may take a little effort to work in the final few.


Home, Sweet Home! You'll need to find a South or East facing location out of the rain to place this in the spring. Secure it so it doesn't move around. Keep an eye on it to see what happens.
Home, Sweet Home! You’ll need to find a South or East facing location out of the rain to place this in the spring. Secure it so it doesn’t move around. Keep an eye on it to see what happens.

Fun Phineas Facts

We’ve noted the many good qualities of Mason Bees and said they are non-aggressive and unlikely to cause much trouble in the stinging department. It natural for anyone who has been stung by a bee to suspicious of anything with a stinger. Classification – organizing things into orderly categories – is a basic part of good science, and you can practice on “bees.” Even while running away. The first step is to try to avoid calling everything that might deliver a “bee sting” a “bee.”

Do you mean Bee or Wasp? Or Yellowjacket? Or Hornet? The differences matter, since some stinging insects are classified as flower-lovers and others as predators (although, of course, not of humans!). Here is a link to a good article from the Cooperative Extension service at Colorado State University to get you started thinking about the differences.Wasp-Hornet-Yellowjacket-Bee?

One of the best ways to distinguish between types of flying insects with stingers is to notice where they live. If the insect in question lives in a honey-filled wooden box on a honey farm, that’s an easy one. If it lays eggs in the bee house you construct, that narrows it down, too. Here is an article that has a great chart about other types of insect housing you might encounter. How to Tell the Difference Between the Stinging Wasps.

6. How to Think Like a Scientist – The Custard Effect

How to think like a scientist for kidsCustard makes me puke. Violently. Specifically, chocolate custard. It’s my working hypothesis. I only have two data points, but that’s enough for me. Talking like a scientist, chocolate custard causes me to puke. The effect of me eating chocolate custard is: me puking. The arrow of cause ==> effect is one way. My need to puke did not cause me to eat chocolate custard.

Cause and effect. Every scientist studies causes and effects. The cause happens first, and then later there is an effect. Always. It’s so obvious that at times we forget. Cutting onions make me cry. Onions cause me to cry. The effect of cutting up onions is crying. And crying does not cause me to cut onions.

But, when I cut onions, I also always listen to the radio. These two things happen in pairs, but are completely unrelated.

This leads to one of the most important parts about thinking like a scientist: just because things happen together, does not mean that one necessarily caused the other, or that they are even related. Talking like a scientist, if things happen together it is called “correlation”. The biggest mistake people make is when they assume correlation also means causation. There is a correlation between the onions and listening to the radio, but there is no causation.

My favorite football team wins when I wear my lucky T-shirt. Did me wearing my “lucky T-shirt” cause (or even help) my team to win? Probably not. It’s more likely that I often wear that shirt on game days, and my team wins a lot. Correlation does not mean causation,

But sometimes it’s hard to know what’s going on. Thinking like a scientist, I observe:

Every night my dog barks at midnight.

How does my dog know its midnight? She even adjusts for daylight savings time! Is it magic? Does the clock cause my dog to bark?

No! After further investigation, it turns out that she barks every night at midnight because that’s when my neighbor lets his dog outside. Midnight and my dog barking have a correlation. But the cause of the barking is my neighbor’s dog. The time of night had nothing to do with it.

But sometimes it’s hard to know what causes what.

Suppose you find that all the kids who wear glasses also sit in the front row of your class. Does sitting up close cause their eye problems? Or are they sitting up close because they have eye problems?

The great thing about noticing correlations is that it leads to ideas for new hypotheses and experiments. The experiments will provide evidence either supporting causation or falsify the idea.

For instance, I could ask my neighbor to let his dog out at 10pm to see if my dog will bark early. Or I could do custard flavor experiments. Maybe I only puke on chocolate custard and I will love strawberry custard…


Fun Phineas Effect Facts
One of the most common grammar mistakes in the English language is confusing the words ‘effect’ and ‘affect’. Wow your English teachers by never mixing them up.

Effect with an E is a noun, meaning ” the result of”. What was the effect of me eating chocolate custard? Puke.

Affect with an A is a verb meaning “to influence or change”. Verbs are action words. Remember: A for action. Bad weather affects my mood. So does puking.

5. How to Think Like a Scientist – Controlling the Chocolate Chip Experiment

phineas_scientist001So I learned how to make my mother’s delicious chocolate chip cookies. But after a few batches I got bored, and like a scientist, started to experiment. My mom didn’t enjoy walnuts and rarely baked with them, but I love them. I decided to change her recipe and add walnuts to my mix. Success! My roommates and I thought they tasted great (except for my friend Tony, who is allergic to nuts).

But were the cookies better than the original recipe? It was hard to know. It was hard to remember exactly how the originals tasted. So, thinking like a scientist, the next time I divided the cookie dough into two bowls and added walnuts only to one of them. I baked both batches and we did a taste test. The walnut chocolate chip cookies were clearly superior. And Tony was happy.

Talking like a scientist, the batch of original recipe cookies was the control group and the walnut batch was test group. The original ingredients are called dependent variables and the walnuts the independent variable.

The mark of a good experiment is that it is a controlled experiment with only one independent variable. You only want to change one thing at a time so you know what you are testing. The control allows you to compare the results of the change.

It is fine to do an uncontrolled experiment (like I did with my first attempt at walnut cookies). But if the results are good, it should be followed by a controlled experiment to verify them.

Scientists use uncontrolled experiments to generate ideas for new hypotheses. Hey, what if I throw in some jalapeño peppers into the cookie dough?

Fun Phineas Fact
In medical research, controlled experiments are called clinical trials. Over the years, it has been shown that the results are more accurate if the patients don’t know whether they are in the control group or the test group. We call these blinded trials.

Think about doing a soda pop taste test with your friends. Then try it again putting a blindfold on them before they drink. Blinding prevents personal opinions from altering results.

It has been found that results are even more accurate when the doctors and nurses running the experiment don’t know which group is the control. We call these double blinded trials. A double blinded controlled trial is difficult and expensive to run, but is the gold standard of medical research.

The US Food & Drug Administration requires double blinded clinical trials be run before approving new medications.

4. How to Think Like a Scientist – The Chocolate Chip Experiment

phineas_scientist001My mother baked incredibly delicious chocolate chip cookies. A few times a year she would bake a huge batch of them. Every time they tasted the same… awesome. When I left for college I asked for the recipe. I am not a cook, but, heck, I can follow directions. How hard could it be?

Lets just say that my first attempt was a disaster. Instead of soft and gooey like hers, mine were hard and crunchy like bricks. And they tasted nasty. I tried again, this time being extremely careful to follow the recipe exactly. Same result! What was I doing wrong? It was time for me to think like a scientist to figure it out.

cookieThe next time I went home, I watched my mother very carefully as she baked them. I noticed four differences from my failed attempts:

  1. A missing ingredient. Cinnamon. Just a dash. Mom just shrugged when I asked her. Cooking is so natural to her, she didn’t even think about it. And she doesn’t even look at the recipe as she bakes.
  2. Speaking of dashes. The actual quantity of “a dash” varied from almost microscopic to a heaping spoonful depending on the spice.
  3. She used real butter instead of margarine as listed on the recipe.
  4. She removed cookies quickly from the baking sheet and placed them on a plate to cool. Apparently every cook knows this, so she didn’t write it down. I left mine on the pan to cool, and they continued to cook way too long, turning into crunchy bricks.

Armed with these insights, I attempted a third batch of cookies in my college apartment. And to the relief of my roommates, success! I nailed it perfectly.

My chocolate chip experience shows the importance of repeatability. My mom’s perfect cookies weren’t a fluke or accident, she could consistently make more any time. And just as important, I was able to get the same results when I used the same ingredients in the same quantities and followed the same steps.

Experiments following the scientific method must be repeatable by you and others. First, you as a scientist should be able to run the experiment many times and get consistent results. And just as important, other people, even your un-best friend, should be able to get similar results if they follow the same steps. If it’s not repeatable, it’s not believable. And if it’s not repeatable it’s not believable. (That was a joke).

As an experimental scientist, you must write down every detail about the experiment, even details you think are irrelevant. The day and time, the weather, the type of materials used, the location, exact quantities… everything that might affect the outcome. It would be terrible to get great results and not be able to recreate the experiment later. Think of my first batch of nasty cookies.

Here is my mom’s cookie recipe!

Rita’s Chocolate Chip Cookie Recipe (with my corrections)
Chef: Rita M. Kaufman

Ingredients

  • 1 cup + 2 tablespoons all-purpose flour
  • 1/2 teaspoon baking soda
  • 3/4 teaspoon kosher salt
  • 1/2 cup (1 stick) butter, softened
  • 1/4 cup granulated sugar
  • 1/2 cup brown sugar
  • 1/2 teaspoon vanilla extract
  • 1 large egg
  • 1 dash (1/8 tsp) cinnamon
  • 1 cup (6-oz. pkg.) Semi-Sweet Chocolate Morsel

PREHEAT oven to 375° F.

Line a baking sheet with parchment paper and spray lightly with nonstick cooking spray. Set aside.

COMBINE flour, baking soda and salt in small bowl. With an electric mixer on medium-high, or a wooden spoon, beat butter, granulated sugar, brown sugar and vanilla extract in large mixer bowl until creamy (about 20 minutes). Add eggs. Gradually beat in flour mixture. Stir in morsels. Drop by tablespoon onto baking sheet.

BAKE for 9 to 11 minutes or until golden brown. Cool on baking sheets for 1 minutes, move cookies to a plate to cool completely before serving (about 15 minutes).


Fun Phineas Fact
Where you live may affect how you bake. My mom’s recipe was written for cooking near the ocean. If you live at a higher altitude, like Colorado, you will need to make changes to get the same results. At high altitudes, water boils quicker, cookies bake slower, and dough rises faster. Check with a local cooking expert to make adjustments for your kitchen.


References

Website: Betty Crocker Baking Guide

Podcast: Skeptics Guide 5×5 episode 65.