1. Scientific Problem Solving2
Scientific Methods
Step-by-step procedures of scientific problem solving are called scientific methods.
Solving any problem scientifically involves several steps.
The steps used can vary from situation to situation and aren’t always done in the same order.

2. Scientific Problem Solving2
Recognize the Problem
The first step in using a scientific approach to solving a problem is recognizing a problem.
A scientific problem is a question that can be answered using scientific methods.
To solve a problem, scientists must do research using various sources of information.

3. Scientific Problem Solving2
Observe
In order to be able to answer the question, a scientist needs to plan and carry out an experiment.
First, he or she must make and record careful observations about the subject.

4. Scientific Problem Solving2
Observe
Observations can be bits of information you gather with your senses.
Most scientific observations are made with your eyes and ears.
You also can observe with your senses of touch, taste, and smell.

5. Infer 2 Observations often lead to inferences.
Scientific Problem Solving 2
Infer
Observations often lead to inferences.
An inference is a conclusion about an observation.

6. Scientific Problem Solving2
Form a Hypothesis
After a problem is identified, a scientist might make a hypothesis.
A hypothesis (hi PAH thuh sus) is a statement that can be tested.
Hypotheses are based on observations, research, and prior knowledge of a problem.
Sometimes more than one hypothesis can be developed.

7. Scientific Problem Solving2
Form a Hypothesis
Hypotheses differ from two other scientific statements—scientific theories and scientific laws.

8. Scientific Problem Solving2
Test Your Hypothesis
An experimental investigation is a series of carefully planned steps used to test a hypothesis.
In any experiment, it’s important to carefully consider what resources you will use and how to conserve them.
It’s also important to keep everything the same except for the item or variable you are testing so that you’ll know which variable caused the results.

9. Scientific Problem Solving2
Test Your Hypothesis
The one factor that you change in an experiment is called
the independent variable.
For example, in an experiment, similar-sized fig plants received the same amount of sunlight.

10. Test Your Hypothesis 2 They were planted in similar containers
Scientific Problem Solving 2
Test Your Hypothesis
They were planted in similar containers
with the same type and amount of soil.
The hypothesis to test is that fig plants grow best when watered only once a week.

11. Scientific Problem Solving2
Test Your Hypothesis
The independent variable is the number of times he waters each plant in a week.
The growth of the plants is the dependent variable.
A dependant variable is the factor, or outcome, that will be measured in an experiment.

12. Scientific Problem Solving2
Plan the Experiment
In order to test only one variable at a time, scientists often use constants.
Constants are factors in an experiment that stay the same.

13. Scientific Problem Solving2
Plan the Experiment
Some experimental investigations also have a control. A control is a standard used for comparison.
If a scientist wished to study the chemical makeup of a soil sample. A control soil—one of known chemistry— could be analyzed first.
That way, data from the sample of interest could be directly compared to data from the control soil.

14. Scientific Problem Solving2
Do the Experiment
In the fig plant experiment, plant A would only be watered once, at the beginning of the experiment.
A second fig plant, plant B, would get watered everyday.
The third fig plant, plant C, would get watered once each week. The experiment would last one month.

15. Number of Leaves Dropped
Scientific Problem Solving 2
Do the Experiment
Tables can be used for recording observations.
These will list each plant and the number of times it was to be watered.
Plant
Date Watered
Plant Height
Leaf Color
Number of Leaves Dropped A B C

16. Number of Leaves Dropped
Scientific Problem Solving 2
Do the Experiment
Observations, which would include the height of each plant, the color of its leaves, and the number of leaves it dropped, if any, should be recorded.
Plant
Date Watered
Plant Height
Leaf Color
Number of Leaves Dropped A B C

17. Analyze Your Data 2 Data are collected during any scientific study.
Scientific Problem Solving 2
Analyze Your Data
Data are collected during any scientific study.
Some data are numeric values such as the length of an object or the temperature of a liquid.
Other data you collect may include observations that use adjectives and phrases such as faster, smaller, not as well as, and greener.
An experimenter must record and study the data collected before he or she can draw conclusions about an experiment.

18. Scientific Problem Solving2
Analyze Your Data
By the end of the month in the fig experiment, the leaves still left on the plant that was watered only once were brown and shriveled. It had lost most of its leaves.
The plant that was watered everyday had a few leaves left on its branches, but these leaves didn’t look too healthy.

19. Scientific Problem Solving2
Analyze Your Data
The plant that was watered once each week had grown the tallest.
Many healthy green-and-white leaves extended from its branches.

20. Draw Conclusions and Communicate
Scientific Problem Solving 2
Draw Conclusions and Communicate
A conclusion is a statement based on what is observed.
It can be concluded in the fig experiment that not watering a plant enough causes the leaves to dry out and die.
Watering a plant too much also causes the leaves to die.
Watering the plant once a week seems to be the best schedule, of those tested, for a fig plant.

21. Draw Conclusions and Communicate
Scientific Problem Solving 2
Draw Conclusions and Communicate
The hypothesis was supported.
But in order to make sure his conclusions were valid, he should repeat his experiment.
An important step in the scientific process is to communicate the results of an investigation.

22. Question 1 Answer 2 List the steps in the scientific method.
Section Check 2
Question 1
List the steps in the scientific method.
Answer
The steps of the scientific method are: identify the problem, form a hypothesis, test your hypothesis, analyze your data, and draw conclusions.

23. Question 2 Answer 2 What is an independent variable in an experiment?
Section Check 2
Question 2
What is an independent variable in an experiment?
Answer
An independent variable is the factor that you change in an experiment.

24. Question 3 2 Compare and contrast an observation and an inference.
Section Check 2
Question 3
Compare and contrast an observation and an inference.

25. Section Check 2
Answer
An observation is information gathered by the senses. Observations can be something you see, hear, smell, taste, or feel. An inference is a conclusion about an observation. It is a guess as to why something occurred.

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