Scientific Method

Brother Gregory speaks to his class,

The subjects for today's lesson is the scientific method, or 'what do scientists do all day'? You must follow the lesson, answer the questions, then complete the required research investigations.

"Let us begin .......

"One day my good friend, Brother Matthew, asked me if my feet hurt.

"Why?" I asked him in return.

"Because every time your feet hurt, it rains tomorrow," he told me. "I'm going on a trip, and I want to know what the weather will be like while I am away."

"When I stopped laughing, I found that I was intrigued by the idea that the condition of my feet could possibly predict totally different events, like the weather. After all, there are strange and mysterious forces in nature, which can do all manner of things in amazing ways, so why not my feet?

"Meteorology had interested me for some time, and I had read somewhere that environmental factors, such as air pressure, air temperature, moisture in the atmosphere and even the kinds of clouds, could all be used to predict if it was going to rain tomorrow.

"I also know that many people, like Brother Matthew, believed that cows, sunsets, caterpillars and yes, even feet, could also predict the weather. Who was right? I decided to find out.

"We are living in an age that will one day be called 'the dawn of modern science, and I feel that my work and research on pea hybrids, and what it all means, are good examples of how scientific investigations could, and should, be carried out. So I used some of the methods I had developed for my other experiments to try and find out about the weather, and if it was possible to predict in advance what was going to happen.

"This type of investigation begins with a simple statement, such as, 'my feet can predict the weather'. In scientific terms, this is called a hypothesis.

"For a scientist, such as myself, this hypothesis is just a beginning. I must now ask himself, 'is this statement true; can my feet predict the weather?'. How was I going to answer this question?

"First I needed evidence; data that I could use to support any later claims I might want to make. In the case of the "sore feet" hypothesis, this data comes in the form of qualitative observations. It works this way.

"Every time my feet were sore I noted down in my book what the weather was like the next day. Was it sunny, was it cloudy, or did it indeed rain?

"What I was looking for was a pattern. After collecting a reasonable number of qualitative observations (basically I was watching something happen), I tried to see if the original hypothesis was correct by determining if the 'sore feet' observation was always followed by a 'rain' observation the next day.

"For a hypothesis to be correct it must accurately predict the future. If there was some sort of mysterious connection between by feet and the weather then the qualitative observations in my note book should show a very clear pattern.

"In the best possible case, the pattern would be that - every time I had sore feet, it rained the next day! This would be a very dramatic outcome, and indicate that there might indeed be a connection between the two events. Such as result would not necessarily 'prove' that my feet could predict the weather, but it might well indicate that something interesting was going on that should be looked into more deeply and more seriously.

"On the other hand, if there was no pattern found in the qualitative observations, then the hypothesis was not correct and must be abandoned as a method of predicting the weather.

"Beware! Very few phenomena in nature are 'all or nothing'. It is very possible to see a pattern in the qualitative observations that possibly indicate a relationship, but, for example, it does not rain every time my feet are sore, only some of the time. Scientists then have to decide if there is a strong enough connection between the two events (the two sets of observations) to justify more research. It is not easy.

"But now it is your turn. I want you to make a set of qualitative observations, keep good notes, find out if there is a pattern and the tell me if you think my feet can predict the weather. Off you go".

First required research
Sore Feet and the Rain
Can my feet predict the weather?

"So, how did it go? "Did it rain every time I had sore feet? Did it rain most of the time my feet were sore? Or would you say that there was no serious connection between my feet and the weather?

"I would like to see your results and conclusions some time... but first, why don't you answer some simple questions about what you did and what you found ...

As you proceed through this lesson, test yourself as you go by answering some of these "true/false" questions.

Other possibilities - can changes in the environment predict the weather?

"I have read that a number of different environmental factors, such as air pressure, air temperature, wind direction and humidity can influence what the weather will be like the next day. This sounds like a much more reasonable idea, but much harder to test. There are many more factors involved. How can we being to see if there are any patterns among the observations?

"Once again, we must start with a hypothesis ... hummmm ... how about suggesting that 'air pressure and temperature influence the weather'.

"This new hypothesis is also testable by the same method we used before. But first, data in the form of qualitative observations must be collected.

"Once again you must collect data in your note books. Carry out the next research investigation and every day note the air pressure, the air temperature, and then record what kind of weather you see.

"As you did before, use your results to look for a pattern and see if there is any connection between the air pressure and temperature, and when it will rain. Go on ....

Second required research
Tempertature and Pressure
Can the environment predict the weather?

"So, what did you find this time?

"Did you fined any sets of conditions that predicted the weather better than when you used my poor sore feet?

"If so, what were they? Did you write them down in your note book? Did any sets of conditions predict that it was going to rain 100% correctly? How close did you get?

"I have a suggestion for you before you try answering the next set of questions - HINT - If you are getting confusing results, try each experiment or set of conditions for at least 20 times. The larger the number of tries, the better the results will be.

Now answer these questions ....

The Scientific Method - the complete system.

"Congratulations, you have been using the scientific method to investigate what factors influence the weather. But this method is not restricted to just meterology!

"Although the investigations may be very vast, and the nature of the phenomena very complex, all scientists using the same basic approach when trying to solve a mystery or understand a new facet of our world.

"In its simplest form, the scientific method usually starts with either a simple question or a simple observation - like the weather, and 'why does it rain?'. Some form of 'generalization' or 'hypothesis' is then proposed to explain what is going on. When this is done, there may be no evidence one way or another that the hypothesis is correct, but as long as it is 'reasonable' then it can be tested - and this is the heart of the method.

"From the hypothesis a scienctist makes a prediction, then tests the prediction to see if it comes true. In our recent investigations we did this by looking at the pattern of events and to see if there was any connection between the feet, the temperature or the pressure of the air, and if it rained - or not!

"If the predictions come true more than they fail, then there is a possiblilty that the hypothesis contains a grain of what we call "truth, but beware, the 'truth' is a notoriously slippery concept.

"Before we talk about 'knowing what is true and what is not' why don't you take a break and play for a while and learn a bit more ...

... about the Scientific Method

Quantitative Observations - measuring things.

"As you probably know, I love honey and spend a lot of my time studying the habits of bees.

"One day I thought I had just made an interesting qualitative observation. It appeared that older bees searched for flowers and nectar at distances that were further away from the hive. While younger bees, it seemed, liked to search for flowers closer to the hive.

"This was an interesting idea, or hypothesis, but could it be tested using the scientific method? Or was it impossible to find out where young and old bees looked for flowers?

"I thought about this problem for some time and then devised the following experiment:

"I sat by the hive and as the new bees emerged for the first time I put a tiny spot of paint on their backs, then I wrote down in my data book the date and time this bee first came out of the hive. In this way I could always identify a single bee again, and I would also know how old it was.

"Then I took my chair, and sat near flowers that bees were visiting and watched to see which bees would come to those flowers and what markings they had on their backs. I recorded which kind of bees stopped to collect nectar and how old they were.

"Then I moved my chair to flowers that were further and further away from the hive and again watched which kind of bees visited them. Every time I saw a bee I noted the color of the paint on its back and thus knew how old the bee was.

"Throughout the summer, as the hive of bees matured and there were more older and older bees, so I repeated the experiment over and over again.

"At the end of a long summer I had a lot of data about the age of bees and where they hunted for flowers and nectar, but did it make any sense?

"Now, I want you to repeat this investigation and see what happens for yourself, and see if you can interpret the results you obtain.

click here to print out
the graph paper
you will need to plot
your results

"In this investigation, choose the appropriate age for the hive (1 through 7), click to start the bees moving, watch what happens and then collect the two sets of results.

"These results represent the number of bees (young and old) collecting nectar at different distances from the hive. Write down your results very carefully.

"When you have done this you will have a lot of "raw data"; just sets of numbers. This raw data is very hard to interpret, so there is a second way of looking at your results. Plot a graph! Look at the bar-graph on the left. Print out the graph paper and make your own graphs for each month of the summer when the bees are flying from the hive.

"Now start your experiment ...

Third required research
Quantitative Observations
does the age of the bee make a difference?

"Did you plot your graphs? What did they look like as the bees got older and older?

"Quantitative data consists of numbers (numbers of bees, distance from hive, age of hive, etc.). In this investigation you have made a series of Quantitative observations. You have counted the number of bees collecting nectar and different distances from the hive. But what does this type of data mean and how should these kinds of results be interpreted?

"For example, in one of the experiments you might have found that at a distance of one unit from the hive, you counted 1 old bee and 4 young bees. Is this result significant? Does it prove the hypothesis that young bees forage closer to the hive than do older bees?

"Also, as the hive ages during the summer months, there are more old bees, and the old bees are more experienced. But young bees are still being born. Are older bees moving further and further away from the hive? Do all young bees stay near the hive, or do bees born later in the summer move further away from the hive?

"These are interesting questions. Look at your data and graphs and see if you can answer them.

Knowing the truth - how to interpret raw data

"The interpretation of raw data begins with the data itself. Although data can come in many forms, usually it has the form of a 'tally' or collection of measurements or observations. These collections of 'samples' become a 'population' of data.

"Such a collection of data is often just a mass of numbers on paper, in which the human mind has difficulty seeing any patterns or form. Presenting the results in the form of a bar graph makes it easier to see the data in form of a visual summary - easy to see and easier to interpret.

"Words, however must be used to describe the properties and parameters of the graph.

"Now that the data is collected and represented, it is possible to begin probing and testing the original hypothesis that got the project started.

"All of which brings up the interesting subject of chance and probablity, a study which started, naturally, with gamblers.

"Gamblers needed to know the odds before they put down their money on a bet, but calculating these odds needs background knowledge as to what is going on.

"How many data points there are in your sample, the 'sample size' is a very important value, as is the possibility of many different outcomes. Both these values can affect your chances of finding the right outcome.

"How you take your samples and the way in which your data looks on the graph has an input into how you will be able to compare the data from the old bees and the data from your younger bees.

"But now it is your turn. You know all about probability. Use your own data to see if there is a significant difference between the distance travelled and the age of the bees in your sample. Good luck!".

Required Readings
for the lesson
Key Concepts in Probability
samples -|- bar graphs -|- descriptive statistics -|- hypothesis testing -|- chance -|- calculating odds -|- sample size -|- outcomes -|- chances -|- sampling -|- distribution -|- comparison

Curiosity -|- Madness

Recommended Reading Meet Brother Gregory
who was this monk?
Science@a Distance
© 2003, Professor John Blamire