The Scientific MethodTHE PROCESS THAT SCIENTISTS USE

Are You Curious?

When we are curious about something, we generally ask a question!

When we wonder about something we want to find an answer!

Scientists have a process that is used to determine the answers to questions that they have!

When scientists perform experiments they are using a process to answer a question.

Let’s Start With An Observation

I read once in a magazine that it is good to put coffee grounds in the soil when you are growing plants!

Should I just believe it? How could I find out if it really

works? I could ask a bunch of people

and just take their word for it, right?

Observations

In science, to observesomething means to use one or more of your five senses to gather information.

Let’s make sure that we know our five senses.

How could you use your five senses if you were asked to observe a chocolate chip cookie?

Qualitative vs. Quantitative

When we use our senses to observe or evaluate something there are two different ways that we can provide information.

There are two words that we need to take a look at: Qualitative Quantitative

The underlined part of these words will help you learn and remember the difference. The root part of the word will remind you of other words!

Qualitative is the “quality” of something; color, texture, shape, scent. Quantitative is the “quantity” of something; the answer will always include a

number.

Let’s Practice

• A Qualitative observation involves color, texture, size, shape; anything to do with quality. Example: the chicks are fuzzy, small and different colors.

• A Quantitative observation involves something with a number. Example: There are eleven chicks.

Inferences

For instance, I could infer by looking at the huge chunks of chocolate in a cookie that it was going to taste amazing!

But….it could happen that the chocolate looked good but wasn’t really REAL chocolate but instead just nasty imitation stuff!

I inferred that it would taste good based on my prior knowledge of how much I LOVE chocolate!

Inferring Let’s try some examples! Ms. Jenemabi has a puppy named Harley. Harley really likes to have

attention. One day Ms. Jenemabi was trying to work at the computer desk and Harley kept running under the desk. Ms. Jenemabi knows that whenever Harley does this, it is because one of his toys has been left under the desk and he wants her to reach it and throw it for him.

This is called prior knowledge because Harley has done the same thing so many times, so because that is what we already know we infer that it will be the same this time too. Ms. Jenemabi used her foot to feel around for the toy because she was busy. She couldn’t feel it with her foot so she gave in and reached under the desk to get the toy….it wasn’t a toy, it was a BIG UGLY spider!

Predicting Predicting is different than inferring. Both are based on prior knowledge but predicting is something that we think will happen

in the future. A prediction has the word WILL in the answer. Examples:

The football team will win all of their games next fall. It will rain on Tuesday. The track team will take first place.

We don’t really know that these things will happen, we are simply predicting that they will.

Classifying Another skill that scientists use is classifying. Classifying objects or ideas simply means

grouping things based on their similarities or differences.

Let’s go back to these chicks; how could we classify them? You could use what you learned about observation.

The brown ones can be in one group, white in one group and black in another group.

You could try to base your groups on size also.

Let’s Create a Controlled Experiment

All the factors in a controlled experiment are called the variables.

If we want to see if coffee grounds really help plants to grow; let’s do an experiment to find out!

If we want a controlled experiment, we must keep all the variables the same except one.

We Should State Our Hypothesis

A hypothesis is sometimes called an “educated guess”.

It is also referred to as an “IF/THEN” statement.

An example might be, “If I put coffee grounds in the soil of a plant, then it will grow better!”

Let’s Get Started!

In this controlled experiment we will need two separate plants.

One plant will be the control group plant and one will be the experimental group plant.

The experimental group plant is the one that will have the coffee grounds in the soil.

Let’s talk about what variables will be a part of this experiment.

Examples might be: soil, light, water, plants, plant containers, and of course, the coffee grounds.

All Variables Must Be Kept The Same! The containers that the plants will be planted in

must be the same size and made of the same material.

The amount of sunlight that the plants receive must be the same; therefore, the plants must be in the same room at the same temperature.

The plants must receive the same amount of water from the same source.

The soil that the plants are planted in must also be from the same source.

Let’s discuss for a moment why any of this would matter if something wasn’t the same!

Two Important Variables

There are different terms used for these variables and they can be used interchangeably.

The Independent Variable and the Manipulated Variable are the same thing.

The Dependent Variable and the Responding Variable are the same thing.

More on The Variables

The independent variable is the variable that we manipulate to see if it causes a change. Therefore, the coffee grounds would be our independent or manipulated variable.

If the plant with the coffee grounds grows better than the plant without; then the growth of the plant is the dependent or responding variable. Another way to think of it is that the growth of the plant “depended” on the coffee grounds!

Data

For this to be a controlled scientific experiment, we must record data to prove or disprove our hypothesis.

What data do you think we could record to prove or disprove a hypothesis?

Possibilities for Data

We should record the room temperature where the plants are kept.

We should record the amount of water we give each plant.

We should record the hours of sunlight the plants receive.

We should record the growth of each plant.

Now What?

Once we have completed the experiment, then we must analyze the data.

Did the experimental group plant with the coffee grounds grow better than the control group plant?

A true controlled experiment would be repeated several times to show that the data was valid to prove or disprove the hypothesis.

Real Scientists Brag and Challenge!

Scientists report their conclusions or findings to other scientists.

They also create an operational definition which is a little like a set of directions of their experiment to allow other scientists to replicate their work.

It is kind of a challenge to recreate another scientists work!