scientific method and si units updated
TRANSCRIPT
Scientific Method
Scientific Method
Systematic approach used in scientific studies
A logical approach to solving problems by observing and collecting data, formulating a hypothesis, testing a hypothesis, and formulating theories that are supported by data
Scientific Method• Process used by scientists (everyone/anyone) to
determine a solution.• “Method” means there is a consistent and reproducible
way of doing something
• If you need to determine a solution then you must havea problem.
Steps of the Scientific Method
1. Make observations and state the problem
2. Gather information about the problem
3. Form a hypothesis
• Not educated guess because use information from step 2
4. Design/conduct an experiment
5. Gather/analyze data• Data information from an experiment
• Hypothesis Suggested solution to the problem
6. Form conclusion based on data and determine whether hypothesis was correct or incorrect with support data
Steps of the Scientific Method
• Observation • Problem Statement • Hypothesis Statement • Experiment / Data Collection • Conclusion Statement
Steps of the Scientific Method
Types of Observation
Qualitative Data and observations (QL) Color, shape, odor, or other physical
characteristics Quantitative Data and observations
(QN) Numerical information such as
temperature, pressure, volume, the quantity of a chemical formed
Make Observations!
Qualitative Observations Color Smell Texture Shape Anything regarding the
Appearance
Quantitative Observations Length Volume Mass Temperature Speed Density Any type of measurement
(PS)
Variable What does variable mean? To change…
Variables Independent Variable (IV)
aka manipulated variable Only ONE!!! The one the INDividual (YOU) physically change/manipulate
Dependent Variable (DV) aka the responding variable Only ONE!!! The one that changes (or you hope will change) when you change the IV The one you are collecting data about/measuring
Constant Variables MANY of these All the things you want to keep the SAME (do NOT change)
Variables
You should be able to identify the IV and DV from your PS!!!!
Formula:
If…(state what will be done to the IV), then…(state what is predicted to happen to the DV)
CLASS WORKName That Variable!
Control (1):Constants(2) :
Independent (1): Dependent (1):Hypotheses (1):
1. An experiment that tests how quickly different temperatures will dissolve sugar cubes.
2. An experiment that explores how different colors of light impact plant growth.
3. How does the temperature of a chemical reaction change over time?
Experiment a planned way to test a hypothesis and find out
the answer to the problem statement. a way to collect data and determine the value of
the DV. compares the IV to the DV. can only test one DV at a time and change one
IV at a time
Experiment Variables Materials and Procedures Data and Results Section Include observations (QL and QN) Pictures/tables/graphs/calculations
Why Do We Use Graphs? Graphs help us visualize
numerical data. •There are several different
types of graphs: Bar graphs: compare multiple
objects Pie graphs: shows relationships
of parts to a whole Line graphs: show the
relationship between 2 variable
Types of Relationships (between variables)
Direct: as x increases y increases
Indirect: as x increases y decreases
Constant: as x increases y remains the same
A suggested solution to the problem Gathering
Problem
Conclusion Statement Do NOT use 1st person
Me, my, I, we, our, etc… VERY Objective
a summarization that presents the findings of the experiment, what the data shows, and states if the hypothesis was correct (supported) or incorrect (negated)
Restate PS Restate HYP Summarize M&P Analyze and explain data/results (tables, observations, pictures) State whether HYP was correct or not and EXPLAIN why Explain possible errors Explain ways to improve experiment/research Explain APPLICATION to biology and society
After we accept a hypothesis, experiment, and draw a conclusion… Many conclusions that support each other make
up a THEORY Explanation supported by many, many conclusions Many conclusions that support each other over a period
of time Atomic Theory Theory of Relativity CAN be DISPROVEN “The world is flat”
SCIENTIFIC LAW A relationship in nature that is supported by many, many
experiments No exceptions Law of Gravity
At least 3 trials..
Accuracy How close to a measured
value a measurement is capable of providing a
correct reading or measurement
'correct' A measurement is
accurate if it correctly reflects the size of the thing being measured.
Precision Ability to get the same
value more than once (regardless of it is the right value or not)
exact, as in performance, execution, or amount
repeatable, reliable, getting the same measurement each time
This is an accurate pattern, but not precise. The darts are not clustered, but their 'average' position is the center of the bull's eye.
This is a precise pattern, but not accurate. The darts are clustered together but did not hit the intended mark.
This is a randomlike pattern, neither precise nor accurate. The darts are not clustered together and are not near the bull's eye.
This pattern is both precise and accurate. The darts are tightly clustered and their average position is the center of the bull's eye.
SI Units
In science, we need to speak the same language
1795 French scientists develop metric system
1960 International committee meets to
update the system and names it the “Systeme Internationale d’Unites” aka SI
SI Base Units Seven SI base units Base unit
A defined unit in a system of measurement that is based on an object or event in the physical world
Tools of the Trade Mass Scale that measures GRAMS not POUNDS
Pounds are used to measure the force of gravity on your mass…we want to measure the amount of STUFF (Matter) in a thing
Temperature thermometer measures the kinetic energy (KE) /movement of particles
Faster moving particle=more (KE)=higher temp (HOT)
Slower moving particles=less (KE)=cooler temp (COLD)
Volume amount of space object takes up… ruler, measuring tape, etc to measure meters3 (l x w
x h) OR graduated cylinder to measure LITERS
Measure volume at the MENISCUS (curve or dip in the water)
SI Derived Units
Not all quantities can be measured with base units
More than one base unit can be used Speed limit is measure in….
MPH Miles per hour
Which is a combo of what base units? Length and time
Derived Units
Common derived units we will use Speed
Base unit of length and base unit of time Meters/second
Volume 3 base units of length
Length x length x length 1 cm3 = 1 mL
Density Mass/volume Ratio that compares mass of an object to its
volume g/cm3 or g/mL
Density Density=mass divided by the
volume D=m/V Gram/L or grams/m3
How do we figure out volume of odd shaped objects…say a paper clip?
Water Displacement What happens when you fill up the
bath tub to the rim and then get in?
Archimedes Principle Measure known amount of water in
graduated cylinder and record VOLUME (mL)
This is initial volume (Vi) Drop in odd shaped object (paper clip) Record the NEW volume of water
This is final vlume (Vf) Subtract Vi from Vf to get volume of
object (Vo) Vo = Vf- Vi
Get the mass of the paper clip form the scale
Plug the mass (g) and volume (L) into density formula to figure out the density of the paper clip
Class Work!
Suppose a sample of aluminum is placed in a 25 mL- graduated cylinder containing 10.5 mL of water. The level of water rises to 13.5 mL. Mass is 25 g. What is the density of the aluminum sample?
What is the volume of a sample that has a mass of 150 g and a density of 5 g/mL?
Prefixes Used with SI units
Kids Hate Doing Math Dittos Christmas Morning
King Henry Died Monday Drinking
Chocolate Milk
Temperature
SI unit? Kelvin
Our thermometers measure Celsius To convert from Celsius to Kelvin
0o C + 273 = 273 K To convert from Kelvin to Celsius
373 K - 273 = 100o C
Scientific Method Activity
Design an experiment Keep in mind…
Must be measurable Completed in class
Due today Paper with group members names Outline of experiment you will do
Get into groups
A. You noticed that paper airplanes made with different materials fly different.
B. You noticed that certain music helps some people memorize things faster.
C. You noticed that after exercising, students have a harder time remembering/recalling facts.
D. You are wondering if you can jump farther (horizontally ) the bigger running start you get.
E. You are wondering if the size of a tissue paper affects how fast it will reach the ground (velocity).
F. You are wondering if a ball will bounce higher if you drop it from a higher position.