HOW TO DO AN EXPERIMENT. What is Science? The goal of science is to investigate and understand the natural world, to explain events, and to use those.

HOW TO DO AN EXPERIMENT

INTRODUCTION TO SCIENCE & THE

SCIENTIFIC METHOD

What is Science?The goal of science is to investigate and understand the natural world, to explain events, and to use those explanations to make useful predictions.

Science is an organized way of using evidence to learn about the natural world.

Process scientists use to study the world and develop explanations based on evidence.

What is scientific inquiry?

How is science done?

Scientists collect and organize information in a careful, orderly way, looking for patterns and connections between events.

Scientists propose evidence that can be tested by examining evidence.

Scientists make an observation by using their senses to gather information.

A descriptionColorTexture yellow

balloon

Size

blue sky puffy

cloud

Tells how many• Total amount• Length• Mass 3

objects

2 stars

temp: 1500 C

Observations

Qualitative Quantitative

What do scientists do?

Scientists use the scientific

method which is a series of steps

used to solve a problem or

answer a question.

What Are Scientific Methods?

�⃰ Order of the steps can vary- not always the same

*Can use all steps or just some-

it depends on the investigation!

*Steps can be repeated

Scientific Method Steps

1.The problem2.Form a hypothesis3.Design a controlled experiment4.Procedure5.Collect and record data6.Analyze the data7.State your conclusion

Start with a problem that can be solved scientifically.What makes a boat float?

The problem is always written as a question. Why? How? What?

How would you find the density of an object?The problem is measurable.Research What do you know? What do you need?

The Problem

A scientific explanation, an educated guess, or an answer to a question

Based on prior knowledge or observations that can be tested in an experiment

Written in the form

If …. then …. because

If a boat can float then its density is less than water because it does not sink.

Form a hypothesis

Prediction vs Hypothesis

Predictions ARE NOT hypotheses!

A hypothesis explains what did happen.

A prediction is made before you test a hypothesis. *It is what you think will happen *It states a cause and effect

When predictions are shown to be true, the hypothesis is supported.

Testing the Hypothesis

Can test a hypothesis by doing an experiment

Factor

anything in an experiment that can influence the

outcome

Design a controlled experimentThe factors in an experiment that can bechanged are called variables. Some exampleof variables would be : changing thetemperature, the amount of light present, time,concentration of solutions used.

A controlled experiment works with onevariable at a time. If several variables werechanged at the same time, the scientist wouldnot know which variable was responsiblefor the observed results.

An experiment is based on the comparisonbetween a controlled group with anexperimental group.

These two groups are identical except for onefactor.The control group serves as the comparison. Itis the same as the experiment group, exceptthat the one variable that is being tested isremoved.The experimental group shows the effect of thevariable that is being tested.

Example: In order to test the effectiveness of a new vaccine, 50 volunteers are selected and divided into two groups. One group will be the control group and the other will be the experimental group. Both groups are given a pill to take that is identical in size, shape, color and texture.

Describe the control group.

 Describe the experimental group.

 What variables are kept constant?  

What variable is being changed?

Even though the volunteers are given identical looking pills, the control group will not actually receive the vaccine.

This group will receive the vaccine

The size, shape, color, and texture of the pill.

Whether or not the pill contains the vaccine.

PRACTICE

Identify the

variablesThe factor being tested

What is being tested or changed

Only have ONE Comes after “If” in

the hypothesis

The changes that occur because of the experiment

It can be observed and measured

Is the data that is collected

Comes after “then” in the hypothesis

Independent & Dependent

Control – the standard to which the outcome of the test is compared.

ProcedureMake a plan.Test the hypothesis by changing

one variable.Collect materials and tools.Follow directions.Gather information through

observation, making measurements.

•Use senses to make any observations

•Collect measurable information

•Record information on a data table

•Does the data support or not support the hypothesis?

Collect and record data

IMPORTANT REMINDER!!

Repeat, repeat, repeat!*The more times an experiment is done, the more data there is to support or disprove the hypothesis

INTERPRET OR EXPLAIN THE DATA WITH GRAPHS OR

PICTURES

Analyze the data

Conclusion

A logical answer that addresses the original problem, analyzes the data and determines whether or not the data supports the hypothesis.

Experiments must be repeated over and over. When repeated, the results should always be the same before a valid conclusion can be reached.

PAPER AIRPLANES

Practice Problem

THE PROBLEM

Practice Problem

Some paper airplanes fly farther than others. What type of paper makes the best airplane?

FORM A HYPOTHESIS

Practice Problem

If a paper airplane is made using construction paper then it will not travel so far because construction paper has more mass.

THE PROBLEM

Some paper airplanes fly farther than others. What type of paper makes the best airplane?

FORM A HYPOTHESIS

Practice Problem

If a paper airplane is made using construction paper then it will not travel so far because construction paper has more mass.

Some paper airplanes fly farther than others. What type of paper makes the best airplane?

THE PROBLEM

IDENTIFY THE VARIABLESIndependent: construction paperDependent: distance plane traveledControl: force thrown

WHAT IS THE DIFFERENCE BETWEEN THE INDEPENDENT AND THE DEPENDENT

VARIABLES IN AN EXPERIMENT?

QUESTIONS

What is the importance of the control?

WHY IS IT SO IMPORTANT THAT A SCIENTIST ACCURATELY DESCRIBES THE PROCEDURE

USED IN THE EXPERIMENT?

QUESTIONS

In a “controlled experiment”, why must all of the variables, except one,

be kept constant throughout the experiment?