The document describes the scientific method and key concepts in science. It discusses the following: - The scientific method involves systematic observation, experimentation, formulation and testing of hypotheses. - Common graphs used in science include straight lines, hyperbolas, parabolas which show relationships between variables. - The International System of Units (SI) provides standard units for measurement. Conversion factors are used to convert between units. - Scientific notation and rounding are techniques used to simplify large or small numbers with many significant figures.

1. THE SCIENTIST
METHOD 3º ESO
SERGIO SALOBREÑA
LUCENA
FUENGIROLA

2. THE SCIENTIST METHOD
•THE SCIENTIFIC METHOD IS A PROCEDURE THAT HAS
CHARACTERIZED SCIENCE SINCE THE XVII CENTURY, WHICH
CONSISTS OF SYSTEMATIC OBSERVATION, MEASUREMENT,
EXPERIMENTATION, FORMULATION OF HYPOTHESIS,
ANALYSIS OF HYPOTHESIS AND MODIFICATION OF
HYPOTHESES. THIS METHOD ALWAYS FOLLOWS THE SAME
PHASES:
1. FIND A PROBLEM: AFTER OBSERVING NATURE APPEAR
THE QUESTION : WHY SOMETHING HAPPENS?. EXAMPLE:
WHY DOES LIGHTNING APPEAR IN HEAVEN?

3. THE SCIENTIST METHOD
2. FORMULATION OF THE HYPOTHESIS: IT IS THE POSSIBLE
ANSWER TO THE PREVIOUS QUESTION. EXAMPLE: THE
LIGHTNINGS ARE AN ELECTRIC SHOCK THAT HAPPENS
NATURALLY IN A STORM.
3. CHECKING THE HYPOTHESIS:
A)PLAN AN EXPERIMENT WITH WHICH YOU CAN CHECK IF
YOUR HYPOTHESIS IS CERTAIN: FOR EXAMPLE, YOU PLACE A
LIGHTING ROD JOINED TO AN ELECTRIC METER AND
OBSERVE THAT EFFECTIVELY, WHEN A RAY REACHES THE
OBJECT IT IS MEASURED A LARGE ELECTRICAL DISCHARGE.

4. THE SCIENTIST METHOD
B. OBTAINING AND ANALYZING DATA: AFTER MEASURING THE
ELECTRICAL DISCHARGES RECORDED IN A STORM NIGHT,
WE ORGANIZE THE DATA IN A TABLE AND OBSERVE IF THE
DATA OBTAINED ARE THE EXPECTED ACCORDING TO OUR
HYPOTHESIS.
4. EXTRACTION OF CONCLUSIONS: YOU OBSERVE THAT YOUR
HYPOTHESIS IS TRUE, EVERYTIME THAT ANY RAY
REACHES THE LIGHTING ROD YOU REGISTER AN
ELECTRIC DISCHARGE.
5. COMMUNICATION OF RESULTS: YOU MAKE A REPORT IN
WHICH IT REFLECTS THE DEVELOPMENT OF YOUR
INVESTIGATION AND YOUR RESULTS, AND EXPLAINS IT IN
THE COLLEGE AND ANY SCIENCE MAGAZINE.

5. THE SCIENTIST METHOD
DATA TABLES AND GRAPHICS ARE USED FOR THE INTERPRETATION OF DATA.
FROM A GRAPHIC, WE CAN PREDICT THE VALUES THAT ARE LOCATED
AMONG THE STUDENTS VALUES, THAT IS TO INTERPOLATE, AND PREDICT
THE VALUES THAT ARE LOCATED OUTSIDE THE STUDENTS VALUES OR
EXTRAPOLATE. THE FORM OF THE LINE SHOWS THE RELATIONSHIP
BETWEEN THE VARIABLES.

6. THE MOST USUAL GRAPHICS
1. STRAIGHT LINE PASSING THROUGH THE ORIGIN: IT INDICATES THAT WHEN
THE VARIABLE X INCREASES, SO DOES THE VARIABLE Y. THIS RELATION
IS EXPRESSED BY THE FOLLOWING EQUATION: Y=aX. a IS A CONSTANT,
WHICH INDICATES HOW MUCH GROWS Y WITH RESPECT TO X. IF a=2, THE
DEPENDENT VARIABLE (Y) WILL GROW TWICE AS MUCH AS THE
INDEPENDENT VARIABLE (X).

7. THE MOST USUAL GRAPHICS
2. STRAIGHT LINE THAT DOES NOT PASS THROUGH THE ORIGIN: IT
INDICATES THAT WHEN THE VARIABLE X INCREASES, SO DOES THE
VARIABLE Y, BUT WE ADD b, WHICH IS THE POINT WHERE THE LINE CUTS
THE Y-AXIS. Y= aX+b.

8. THE MOST USUAL GRAPHICS
3. HYPERBOLA: A HYPERBOLA SHOWS THAT THE DEPENDENT VARIABLE (Y)
DECREASES WHEN THE INDEPENDENT VARIABLE (X) INCREASES. THEY
ARE SAID TO BE INVERSELY PROPORTIONAL. THE RELATION BETWEEN
THEM IS A CONSTANT (K) WHICH INDICATES HOW MUCH ONE DECREASES
AS THE OTHER INCREASES. THE EQUATION THAT CHARACTERIZES IT IS:

9. THE MOST USUAL GRAPHICS
4. PARABOLA: THIS GRAPH SHOWS THAT THE DEPENDENT VARIABLE (Y)
INCREASES GREATLY WHEN THE INDEPENDENT VARIABLE (X) INCREASES.
THIS IS BECAUSE Y VARIES WITH THE SQUARE OF X, SO THAT AS X HAS A
SMALL INCREASE, Y TRIGGERS ITS VALUE. Y=aX2.

10. FORMULATION OF LAWS AND THEORIES
•. A LAW IS A HYPOTHESIS CONFIRMED BY MULTIPLE EXPERIMENTS. CAN BE
EXPRESSED THROUGH AN EQUATION OR AS A PRINCIPLE.
• THEORIES ARE BUILT TO MAKE RELIABLE PREDICTIONS ON EVEN EVOLVING
PHENOMENA.
• THE MODELS SERVE TO EXPLAIN THE PHENOMENA IN A SIMPLIFIED
MANNER. USUALLY, THEY HAVE AN EDUCATIONAL PURPOSE.

11. MAGNITUDES AND UNITS
ALL OF THOSE PROPERTIES OF THE BODIES THAT WE CAN MEASURE ARE
MAGNITUDES.
TO MEASURE A MAGNITUDE IS TO COMPARE IT WITH ANOTHER QUANTITY
THAT WE USE AS A REFERENCE AND THAT WE CALL UNITY. FOR EXAMPLE,
THE UNITY KILOGRAM IS THE WEIGHT OF A PLATINUM AND IRIDIUM CYLINDER
THAT IS KEPT IN THE OFFICE OF WEIGHTS AND MEASURES OF PARIS.
WHEN WE SAY THAT DAVID'S BACKPACK HAS A WEIGHT OF 3 Kg, IT MEANS
THAT IT CONTAINS 3 TIMES THE WEIGHT UNIT: THE KILO. THE MEASURE IS 3
AND THE UNIT THE KILOGRAM (Kg).
TO MEASURE MAGNITUDES, MEASURING INSTRUMENTS, SUCH AS THE
METRIC TAPE, THE BALANCE, THE THERMOMETER OR THE PLUVIOMETER,
ARE USED.

12. THE INTERNATIONAL SYSTEM OF UNITS
IN 1960, THE INTERNATIONAL SYSTEM OF UNITS (SI) WAS ESTABLISHED.
CONSISTS OF 7 FUNDAMENTAL BASIC MAGNITUDES, WHICH CAN BE
MEASURED DIRECTLY, AND FROM WHICH OTHER DERIVATIVE MAGNITUDES
ARE OBTAINED. FOR EXAMPLE, FROM THE LENGTH AND THE TIME CAN BE
ACHIEVED THE SPEED DERIVED MAGNITUDE.

13. CONVERSION FACTORS
TO TRANSFORM UNITS IN OTHERS WE WILL USE THE CONVERSION FACTORS.
A CONVERSION FACTOR IS A FRACTION WHO EXPRESSING THE
EQUIVALENCE BETWEEN TWO UNITS.
1kg
▬
1000 g
IF WE WANT TO PASS 3000 Km TO THE INTERNATIONAL SYSTEM
1. WE ARE LOOKING FOR EQUIVALENCE BETWEEN Km and m (SI). 1Km = 1000
m 1000m
▬▬
1Km
2. WE MULTIPLY THE MEASURE BY THE CONVERSION FACTOR :
3000 Km x 1000 m
▬▬ = 3000000 m
1 Km

14. CONVERSION FACTORS
TO OPERATE WITH CONVERSION FACTORS IN DERIVATIVE MAGNITUDES LIKE SPEED, WE WILL DO IT IN
THE FOLLOWING FORM:
EXPRESS IN SI UNITS 80 Km/h
1. WE KNOW THAT THE UNIT OF THE INTERNATIONAL SYSTEM FOR SPEED IS m / s. SO WE WILL NEED 2
CONVERSION FACTORS, ONE THAT RELATES Km with m AND ANOTHER THAT RELATES h with s.
2. WE CREATE OUR CONVERSION FACTORS:
WE ALWAYS CREATE OUR CONVERSION FACTORS SO THAT THEY OPPOSE THE AMOUNT THAT WE
HAVE TO CONVERT. OBSERVE Km IS IN THE NUMERATOR SO THAT IN THE CONVERSION FACTOR
WE WILL SITUATE IT IN THE DENOMINATOR; AND HOUR IS IN THE DENOMINATOR SO THAT IN THE
CONVERSION FACTOR WE WILL SET IT IN THE NUMBERER. IN THAT WAY THE REPEATED UNITS
CANCELS AND YOU OBTAIN WHAT YOU WANTED: m / s.
3. WE OPERATE AS IN THE PREVIOUS EXAMPLE:
Km
m
1
1000
s
h
3600
1
sm
s
m
s
h
mK
m
h
mK
/22,22
3600
80000
3600
1
1
100080


15. SCIENTIFIC NOTATION
IT IS USED TO AVOID WORKING WITH LARGE NUMBERS. IT IS TO EXPRESS THE NUMBERS
AS POTENTIALS OF 10.
STEP 1: WE WILL WRITE THE NUMBER WITH A SINGLE WHOLE DIFFERENT NUMBER OF 0
IN FRONT OF THE COMA. FOR THAT WE MOVE THE COMA:
A) 7856.1 ---- 7.8561 B) -0.005612 ----- -5,612
STEP 2: WE MULTIPLY THE AMOUNT FOR A POTENTIAL OF 10.
A) 7.8561 X 10 B) -5.612 X 10
STEP 3: THE EXPONENT OF 10 WILL BE EQUAL TO THE NUMBER OF POSITIONS THAT WE
HAVE MOVED THE COMA.
A) 7,8561 X 103 B) -5,612 X 103
STEP 4: IF WE HAVE MOVED THE COMA TO THE LEFT THE EXPONENT WILL BE POSITIVE,
AND IF WE HAVE MOVED IT TO THE RIGHT IT WILL BE NEGATIVE.
A) 7,8561B X 103 B) -5,612 X 10-3

16. ROUNDING
IT IS USED WHEN A RESULT HAS MANY DECIMAL FIGURES. WE WILL ROUND
THE DECIMAL NUMBER THAT TELLS US THE PROBLEM, AND IF IT DOES NOT
INDICATE ANYTHING WE WILL ROUND TO THE SECOND DECIMAL NUMBER.
STEP 1: WE TAKE THE DECIMAL FIGURES THAT THE PROBLEM INDICATES OR
WE ROUND TO THE CENTURIES:
A) 0,5432 B) 567,895 C) 1347,73654429
STEP 2: IF THE FOLLOWING NUMBER IS 5 OR MORE, WE WILL INCREASE ONE
UNIT THE LAST NUMBER IN RED. IF IT IS LESS THAN 5, WE LEAVE IT THE
SAME. IN BOTH CASES WE DESPISE ALL THE OTHER DECIMALS.
A) 0.54 B) 567.90 C) 1347.74