Scientific Method

Science!

The scientific method

What is science?

Science is the study of the natural world through observation and
experimentation.

Science has many fields like biology and chemistry.

Can you think of any science fields?

What is science?

Science involves looking at the world around you and making observations.
These observations can then be used to create experiments.

An observation is the act of looking at something carefully to gain
information.

An experiment is a procedure to test a hypothesis, make a discovery, or
demonstrate a known fact.

Multiple Choice

Which of these are not an example of an observation?

• Noticing the cup on a table is full

• Noticing your key is blue

• Checking outside for the weather

• Hearing gossip from your friends

Scientific Method

The scientific method is a series of steps one takes when conducting a
scientific experiment.

The first step in the scientific method is to observe. Forming a conclusion
from an observation is called an inference.

●For example, Raymond wants to know which fertilizer will help his
tomatoes grow the best. He observes that Fertilizer X appears to
make his tomatoes grow the most.

The second step in the scientific method is to ask questions. The question
being asked is the problem. It should be specific.

●Which fertilizer makes Raymond’s tomato grow the most?

Multiple Choice

Which of these is a good question you could reasonably test?

• Why is the sky blue?

• Does putting my phone in the fridge help the battery life?

• Why did the dinosaurs die?

• Why is the Earth round?

Scientific Method

The third step is to do research. Search for existing answers or solutions.

●Raymond looks up different brands of fertilizer to see which has the
best reviews.

The fourth step is to form the hypothesis.

What is a hypothesis?

A hypothesis is an educated guess based on research. It is an idea that is
proposed so that it can be tested to see if it might be true.

●Based on observations and research, Raymond hypothesizes that
Fertilizer X will cause his tomatoes to grow the most compared to
Fertilizer A and Fertilizer C .

●To be more sure, he creates an experiment.

Multiple Choice

True/False: A hypothesis is just a random guess.

• True

• False

Experiment

An experiment is the fifth step in the scientific method.

●Raymond plants tomato seeds into 4 different pots. He adds Fertilizer
X to one, Fertilizer A to one, and Fertilizer C to another. In the fourth
pot, he adds no fertilizer. This is to compare the growth of the plants
to a baseline. In experiments, this is called a control.

Collect the data

The sixth step of the scientific method is to collect the data. Measure
whatever outcome of the experiment.

●Raymond measures each tomato plant after a few weeks.

○The control measured 10 cm

○Fertilizer X measured 14 cm

○Fertilizer A measured 16 cm

○Fertilizer C measured 11cm

Analysis

The seventh step is analysis. You examine the data you have collected.

●Raymond compares the results of his experiment

Multiple Choice

Which fertilizer caused the plants to grow the most?

• Fertilizer A

• The control

• Fertilizer C

• Fertilizer X

Data

There are two types of data: Quantitative and Qualitative.

Quantitative, which takes from the word “quantity” is about data you can
count or measure. For example, Raymond’s data is quanitative because he
measured it.

Qualitative, which takes from the word “quality” is about data based on
descriptions. If Raymond wanted to know which fertilizer made his
tomatoes the reddest, this would be qualitative.

Multiple Choice

Which of these is qualitative?

• The number of ants in a colony

• The size of each ant

• The type of each ant

• The amount of eggs the queen lays

Multiple Choice

Which of these is quantitative?

• The skin color of participants

• The types of clothes the participants wear

• The height of the participants

• The eye color of the participants

Conclusion

The final step is the conclusion. Compare the hypothesis to the experiment
results. You can accept or reject the hypothesis.

●Raymond had to reject the hypothesis. Fertilizer X did not make his
tomatoes grow the most.

Rejecting the hypothesis doesn’t mean the experiment was bad, it just
means it had a different outcome than expected. That’s a part of science!

Sometimes, different scientists can look at the same results and come to
different conclusions.

Conclusion

Raymond may not be satisfied with the outcome of the experiment and
wish to do it again. Repetition, or repeating an experiment, allows the data
to be more reliable.

For example, if Raymond repeats the experiment 3 more times, he’ll have 4
total sets of data to compare. If he finds that Fertilizer A continues to cause
the most growth, he can be reasonably sure that Fertilizer A is the best for
tomato plant growth.

Scientific Papers

When a scientist does an experiment, they will publish their findings so
other scientists may see and attempt the experiment themselves. This is to
continue to see how accurate the results are.

Theories

Eventually, if an experiment is repeated enough and continues to have the
same results, it can become a Scientific Theory

A scientific theory is not the same as a regular theory because a scientific
theory has decades of testing or research behind it. For example, the Big Bang Theory

A theory attempts to explain why or how something happens. This is
different than a Scientific Law.

Multiple Choice

Which of these is not a scientific theory?

• The theory of evolution

• The Big bang theory

• Cell theory

• The theory you have about your favorite show

Laws

While theories explain stuff, laws predict what will happen. For example,
the Laws of Gravity state that if you hold an object up and drop it, it will
fall to the ground. This always happens, no matter how many times you
drop something.

A theory cannot become a law.

Scientific Method

Steps of the scientific method are:

Observe/ask questions, research, form the hypothesis, experiment, collect
the data, analyze the data, and reach a conclusion.

These steps are not set in stone and can be changed around depending on
the experiment.

Variables

In an experiment, a variable is anything that changes or can be changed. In
other words, it is any factor that can be manipulated, controlled for, or
measured in an experiment. Experiments contain different types of
variables.

Variables

For example, Raymond and his tomato plants. He was measuring the effect
of different fertilizers on his plants.

The variables, or things that change, would be the types of fertilizers and
the plant heights.

Independent Variable

The variable a person changes is called the independent variable.

For example, in Raymond’s experiment, the independent variable would be
the fertilizer used. He changed the different types of fertilizer to test how
effective they were.

Dependent Variable

The dependent variable is the variable that is being measured or tested in
an experiment.

In Raymond’s experiment, the dependent variable would be the plant
heights. The independent variable (fertilizer types) affects the dependent
variable (plant height).

Multiple Choice

You are testing how much salt in water will make an egg float. The independent variable is--

• The amount of salt

• The type of egg

• Whether or not the egg floats

• The amount of water

Multiple Choice

You're testing whether or not putting gummy bears in water will make them bigger. Which is the dependent variable?

• The size of the gummies

• The type of gummies

• Whether or not you put the gummies in water

• The amount of water

Multiple Choice

You're testing the average age of TikTok users. Which is the independent variable?

• The names of the users

• The age of the users

• Whether or not they use TikTok

• The lifestyle of the users

Multiple Choice

You're testing to see if drinking coffee at night makes it harder to go to sleep. Which is the dependent variable?

• Drinking coffee

• Difficulty falling asleep

• Type of coffee

• Time they wake up

Constants

The things in the experiment that aren’t changed are called constants.
Constants are factors that remain the same throughout the experiment.
You want everything not being measured to be the same so it doesn’t
affect the outcome.

For example, the type of soil used in Raymond’s experiment. Can you think
of any other constants that would be used in his experiment?

Constants

Some examples of constants in Raymond’s experiment would be: the soil
type, the amount of water each plant received, the amount of sunlight each
plant received, the species of tomato plant, and the amount of soil where
the plants were grown.

You really want to make sure all of these are the same so they don’t
accidentally affect the outcome of your experiment.

Multiple Select

You are testing how much salt in water will make an egg float. Which are the constants?

• The amount of salt

• The amount of water

• The type of egg

• Whether the egg floats or not

Multiple Choice

You're testing whether or not putting gummy bears in water will make them bigger. What is a constant?

• The size of the gummies

• The type of gummies

• Putting gummies in water

• The taste of the gummies

Multiple Select

You're testing to see if drinking coffee at night makes it harder to go to sleep. Which are constants?

• The amount of coffee drank

• The type of coffee

• The time the coffee is drank

• Staying up at night

Control

A controlled variable is anything that is held constant or limited in an
experiment. It's a variable that is not of interest to the experiment’s goals,
but is controlled because it could influence the outcomes.

For example, when Raymond tested Fertilizer X, A, and C, he also had a
tomato plant that received no fertilizer. The plant that received no fertilizer
was the controlled variable. This was to compare the growth of fertilizer
use to the normal growth of the plant.

Science is done in metric units

The picture shows the prefix. The base units are meter (length), gram (weight), Liter (volume), and second (time). So a centimeter is 100th of a meter