Thinking Like a Scientist

Objectives

Describe how Lavoisier transformed chemistry

Identify the steps in the scientific method Explain why collaboration and

communication are important in science

Important Vocabulary Scientific method Observation Hypothesis Experiment Manipulated variable Responding variable Theory Scientific law

Origins of Alchemy Alchemy: was the study of matter that came

before chemistry It rose from many different regions of the ancient

world and was practiced as early as 400 B.C. It had two sides: practical & mystical Practical alchemy focused on developing

techniques for working with metals, glass, & dyes

Mystical alchemy focused on concepts like turning lead into gold

Alchemy’s impact Ultimately, alchemists developed the

tools and techniques for working with chemicals

Alchemists developed processes for separating mixtures and purifying chemicals

They designed equipment such as: beakers, flasks, tongs, funnels, and the mortar & pestle

An Experimental Approach to Science

By the 1500’s alchemy was a thing of the past and science flourished

In the 1600’s, the Royal Society of London for the Promotion of Natural Knowledge, the first scientific organization, was formed

They met to discuss scientific topics and conduct experiments

The society’s aim was to encourage scientists to base their conclusions about the natural world on experimental evidence

Antoine-Laurent Lavoisier

Famous chemist of the 1700’s in France

He helped to transform chemistry from a science of observation to a science of measurement

He designed a balance to measure mass to the nearest 0.005 gram

He also through experimentation proved how things burn

As brilliant as he was, it did not save him from the revolutionary guillotine

The Scientific Method Is a logical systematic approach to the

solution of a scientific problem Steps in the scientific method:

Making observations Forming a hypothesis Testing a hypothesis Drawing conclusions Communicating results

They Might be Giants: Scientific Method Song

Monty Python demos the scientific method Big Bang Theory: Scientific Method

Making Observations Requires using your senses to obtain

information This information can then lead to a question

to be answered For example, while on vacation in Alaska

you observed the aurora borealis This leads you to ask “What causes the

different colors of light?”

Testing Hypotheses Using our previous example, we proposed that

the different colors of light are due to different gases.

Coming up with a possible explanation for an observation is called a hypothesis

The procedure for testing a hypothesis is called an experiment

When we design an experiment, we have to deal with variables, or factors that change

What could we do for an experiment to test our hypothesis?

Manipulated Variable vs. Responding Variable

Manipulated Is the variable you

change in an experiment

Also called the independent variable

What would our manipulated variable be?

Responding Is the variable you

observe during the experiment

Also called the dependent variable

What would our responding variable be?

Developing Theories Once a hypothesis meets the test of repeated

experimentation, it may become a theory A theory is a well tested explanation for a

broad set of observations For example: chemistry’s focus is the

fundamental structure of matter theory Theories allow us to predict the behavior of

matter or visualize processes that we can not see

Theories can change and can be disproved

Scientific Laws A scientific law is a concise statement

that summarizes the results of many observations and experiments

For example: we will discuss the gas laws A law doesn’t try to explain the relationship

it describes A theory is required for an explanation

Collaboration & Communication

Collaboration Is the joining of

scientists, usually from different areas of expertise to solve a problem

It is a practical choice since no one is an expert in everything

However, it isn’t always a smooth process

Communication Is essential for sharing

scientific ideas with other scientists as well as the public

The methods have changed with the development of technology

However, scientist still publish their work in scientific journals