Chemistry H Unit 1

What is the scientific method?

a series of logical, iterative steps designed to test ideas and answer questions based on evidence

step 1 of the scientific method

recognize a problem / establish objective

step 2 of the scientific method

observe

• draw on past experiences

• review prior research

• note accidental discoveries

step 3 of the scientific method

create a hypothesis

What is a hypothesis?

educated guess that implies cause-effect relationship

e.g., “If a plant is given more sunlight, then it will grow taller than a plant given less sunlight.”

step 4 of the scientific method

experimenting / testing

• conduct controlled experiments

• collect measurements and data

step 5 of the scientific method

theorizing

• conclusions drawn

• generalizations made

• models formed to predict behaviors

note: hypothesis modification, retesting, or a change in test design may occur before theorizing

What is a scientific law?

describes how something in nature will behave under certain conditions, but not why

• statement of consistent, observable pattern

e.g., Law of Gravity describes how an apple falls but not why gravity exists

What is a scientific theory?

detailed explanation for why something in nature happens; well-supported explanation for range of observations

e.g., Theory of Evolution explains how and why different species have changed over time, based on evidence from fossils, genetics, and more

note: theories are not facts.

• when new evidence shows an old theory is incorrect, it is replaced with a new theory that better explains the information