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

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

(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

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

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

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 dm3 = 1 L

Density Mass/volume Ratio that compares mass of an object to its

volume g/cm3 or g/mL

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 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