Scientific Inquiry PPT

1. NKCSD eChemistry
Scientific Inquiry

2. What is Science?
• Science
– is the discovery of
facts
– is the formulation of
laws or principles that
can be tested
– is not limited to the
laboratory!
2

3. The Scientific Inquiry Process
There is no set path that a scientific inquiry must
follow. Different scientists may choose different
paths even when studying the same event.
1. Identify the Problem/Question
2. Collect Background Information
3. Form a Hypothesis
4. Test the Hypothesis
5. Analyze the Results
6. Draw a Conclusion & Communicate Results 3

4. The Scientific
Inquiry Process
4

5. 1. Identify the Problem/Question
Careful observations lead to questions
• Scientific questions must be precise and
answered through observation, measurement,
testing, or analysis of research.
– Bad question: How big is a watermelon?
– Good question: What is the mass of the average
watermelon?
Scientific Question Template:
“What is the effect of the IV on the DV?” 5

6. Limitations of Science
There are 5 categories of questions that science
cannot answer because they are not testable.
Science can’t answer questions about:
1. values
2. aesthetics
3. morality
4. religion
5. supernatural 6

7. 2. Collect Background Information
• Scientists look for research that has already
been done on their topic to determine if they
are duplicating a past experiment, building on
a previous experiment, or doing something
new.
• You can gather the existing facts and ideas
from books, journals, etc. that provide insight
regarding your problem/question.
7

8. 3. Form a Hypothesis
• A hypothesis is a prediction about the
relationship between variables that can be
tested.
• Four important characteristics of a hypothesis
– it is testable, falsifiable, easily measured, and
usually written as an if/then statement.
Hypothesis Template:
“If I (increase/decrease/change) the _______,
then the _______ will (increase/
decrease/stay the same).”
IV
DV
8

9. Writing Hypotheses
Practice Scenario:
A student wants to see if the amount of sunlight
affects the growth cycle of a pansy. The student
places one pansy on a window sill (natural light)
and another in a lit closet (artificial light).
ANSWER: If I increase the amount of sunlight,
then the pansy will grow taller.
9

10. 10

11. 4. Test the Hypothesis
Scientists keep a detailed, written record of what
they do during an experiment, which allows
other scientists to review the work and repeat
the experiment.
• An experiment is a repeatable procedure that
is used to test a hypothesis.
– The procedure is a step-by-step plan that
indicates how materials are used and what
will be done. It will also identify variables,
groups, sample size and number of trials.11

12. Variables
• The independent variable (IV) is the factor
that is purposefully changed in an experiment.
• The dependent variable (DV) is the factor that
is measured in an experiment (your results).
• A constant is any factor that remains fixed in
an experiment because it could influence the
results.
12

13. Identifying Variables
Practice Scenario
A student wants to see if the amount of sunlight
affects the growth cycle of a pansy. The student
places one pansy on a window sill (natural light)
and another in a lit closet (artificial light).
IV- amount of sunlight
DV- growth
Constants- soil, pot, amount of water… 13

14. “Fair” Test
• An experiment must be carefully designed to
isolate and test a single variable at a time. This
is the only way that the experiment is
considered a “fair” test.
Evaluate the experiment below for “Fair” Test:
14

15. Groups
• The control group is the group used for
comparison that does not receive the factor
being tested (the IV).
• The experimental group is the group receiving
the factor being tested. There can be more
than one experimental group in an experiment.
15

16. Sample Size & Number of Trials
• The sample size (N) is the number of
subjects/objects involved in the experiment.
• Scientists normally conduct multiple trials, in
which they repeat an experiment following the
same steps. This allows them to check the
results for accuracy.
16

17. Reliability & Validity
Scientists want their experiments to be reliable
and valid.
• Reliability is the repeatability of the
experiment.
• Validity is the extent to which the
experimental results can be generalized to
other settings or situations.
Reliability and validity can be increased by
increasing sample size and number of trials. 17

18. 5. Analyze the Results
• All information (data) gathered during an
experiment needs to be interpreted to
determine its meaning.
• Scientists evaluate the value/significance of
the data, and check to see if there are any
patterns/relationships amongst the variables.
• Data comes in many forms – notes, graphs or
tables, measurements, and calculations.
• Data is categorized as qualitative or
quantitative. 18

19. Qualitative vs Quantitative
Qualitative Data
Information expressed
using words that describe
the characteristics of the
subject, usually observed
using the five senses.
• Described in words.
• Can be observed but not
measured.
• Examples: color, texture,
smell, taste, appearance,
etc.
Quantitative Data
Information expressed in
numbers, usually measured
using scientific tools.
• Described in numbers.
• Can be observed and
measured.
• Examples: length, height,
area, volume, weight, speed,
time, temperature, humidity,
sound level, cost,
membership number,
age, etc.
19

20. Qualitative Data
• robust aroma
• frothy appearance
• strong taste
• glass cup
Quantitative Data
• 12 ounces of latte
• 1500F serving temperature
• 7 inch tall serving cup
• cost $4.95
20

21. Graphing Quantitative Data
Graphs are used to show patterns and relationships
between variables.
STEPS FOR GRAPHING
• Title: statement of relationship between the two
variables, e.g., DV vs IV
• Use a consistent scale on both axes, utilize space
• Label axes, include unit of measure
• DV is plotted on the vertical (y) axis
• IV is usually plotted on the horizontal (x) axis
• Plot data correctly and draw line-of-best-fit 21

22. Types of Graphs
• Bar Graph: bars are used to
show the magnitude of the data;
used for comparison of multiple
objects that can stand alone.
• Line Graph: lines are used to
show the relationship between
variables (change over time);
used for showing trends and
predictions.
• Pie Graph: wedges are used to
show data as parts of a whole. 22

23. 6. Draw a Conclusion &
Communicate Results
• Based on the analysis of the data, conclude whether
or not the results support the hypothesis. A
conclusion is a decision or claim based on
investigation and evidence.
• The conclusion indicates the relationship between
the IV and the DV (it is an explanation of what the
results show).
Conclusion Template:
“The hypothesis was (accepted/rejected)
because ...” 23

24. 24