1. Scientific Method Observe Experiment Research Draw Conclusions
Form a Hypothesis
Test a hypothesis

2. Scientific Method

3. Observe
Observation- the process of obtaining information by using your senses (sight, touch, taste, hearing, and smell) Science is all about observing our natural world and trying to figure out why things happen and learn to predict what things may happen in the future. Once an observation is made, the next step is to form a hypothesis. (The first scientific observations were made in China Thousands of years ago)

4. Hypothesis
Hypothesis- an idea or explanation based on observations and research, must be able to be tested by performing experiments.
Example: Houseplants given a large amount of sunlight will grow faster than plants given a smaller amount of sunlight.

5. Designing an Experiment
Scientific experiments must be well documented so they can be reproduced and reviewed by peers
most experiments test one independent variable
Independent variable- a factor being deliberately manipulated
Dependent variable- the factor that changes as a result of the manipulation.
This is what will be measured
This “depends” on the independent variable
Control Group- a run in the experiment in which no manipulations are made to the independent variable, this will serve as the baseline to compare all other runs to. (normal level of sunlight)
(in a controlled experiment) all other factors in an experiment should be identical to ensure that the changes of the dependent variable are due to the manipulation of the independent variable.
Experimental Group- runs in the experiment in the independent variable has been manipulated
(the more repetitions you have of any experimental group can make your findings more meaningful

6. Designing an Experiment
Examples:
Independent variable- The amount of sunlight the house plants receive
Dependent variable- how the plants respond to the different amounts of sunlight
Height, mass, etc
Control group- run with natural amount of sunlight to compare the runs with more and less sunlight to
All runs should have plants of the same species, the same amount of water, same kind of soil, etc.
Experimental groups-runs with lights to increase the light, and runs with shades to decrease the amount of light

7. Measurements and Analysis
To draw conclusions measurements from your experiment must be analyzed
The “International System of Units”(SI) is used when taking measurements in a scientific experiment so the data can be analyzed by scientists all over the world
These units are all based on units of 10- metric system

8. SI Units
Length
Mass
Volume
Time
Temperature

9. SI Units Length (kg) kilograms Mass (L) liters Volume (s) seconds Time
(K) kelvins
Temperature
(m) meters

10. Converting SI Abbreviation prefix value Scientific notation E exa
1,000,000,000,000,000,000
10^18 P
peta
1,000,000,000,000,000
10^15 T
tera
1,000,000,000,000
10^12 G
giga
1,000,000,000
10^9 M
mega
1,000,000
10^6 k
kilo
1,000
10^3 h
hecto
100
10^2 da
deka 10
10^1
Unit (meter)
N/A 1
10^0 d
deci
0.1
10^-1 c
centi
0.01
10^-2 m
milli
0.001
10^-3 μ
micro
0.000,001
10^-6 n
nano
0.000,000,001
10^-9 p
pico
0.000,000,000,001 f
femto
0.000,000,000,000,001
10^-15 a
atto
0.000,000,000,000,000,001
10^-18
Converting SI

11. Scientific Notation
Science often deals with really small or really large numbers so in order to make them more manageable we use scientific notation
Example:
Earth’s distance to the sun is146,000,000km or 1.46x10^8km
Length of a red blood cell is m or 6x10^-6m

12. Graphs and charts
Graphs and charts can be used to help visualize and interpret data
Common graphs
Pie chart
Scatterplot
Bar graphs

13. Pie Chart A circle divided into portions representing a whole
This type of chart is good for showing percentage or proportion data

14. Scatter Plot/ Line Graph
Good for showing data over time

15. Bar Graph
Good for showing data over time or comparing categories of data

16. Accuracy vs. Precision
Accuracy- how close a measurement is to the true value
Precision- exactness of a measurement
A measurement in millimeters is more precise than a measurement in centimeters.

17. Significant Figures
Any digit that carries meaning in regards to the precision of your measurement
0.052
370.
10.0
37,000

18. Significant Figures
Any digit that carries meaning in regards to the precision of your measurement
37,

19. Error
Error- The amount of imprecision or variation in a set of measurements
Percent error- how far off the measurement is from the accepted value
PE=((accepted-experimental)/accepted)X100
Confidence interval- the percent of measurements in an experiment that fall within a range of measurements
The average ear of corn in a field is 23cm and 90% of the ears are within 3cm of the average
The average length of corn is 23cm+- 3cm with 90% confidence

20. Drawing Conclusions After many experiments a conclusion can be made
If the results match what was suspected in your hypothesis, then it supports your hypothesis *does not prove
If your results do not match your expectations then your hypothesis is not supported and further experiments can be ran and the hypothesis may be altered.
It is not a failed experiment if your hypothesis is not supported

21. Models
In nature it is nearly impossible to have a controlled experiment so models are used
model- description, representation, or imitation of an object, system, process, or concept

22. Types of Models
Physical Models- three dimensional models that can be touched
Graphical models- two deminsional models such as charts and maps
Conceptual models- model that represents how a system is organized or how it works
Mathematical models- mathematical equations that represents the was a system or process works
Computer models- computer programs that represent simple processes or complex systems where variables can be manipulated and the outcomes can be predicted.

23. Acceptance of Scientific Ideas
Results of an experiment must pass a peer review (panel of experts of the field) to be published.
Once findings have been replicated several times and not been contradicted they may become a theory
Theory- explanation that is consistent with all existing tests and observations