1. UNIT: Chemistry and Measurement
TOPIC: Chemistry and the Nature of Science
Objectives: Lesson 1 of 4
You will learn the importance of chemistry and the problem solving nature of Science
You will understand the scientific method and the steps involved
You will be able to distinguish between a scientific Hypothesis, Theory, and Law
You will become familiar with some basic terms and principles of lab investigation, such as dependent, independent, and control variables

2. Quickwrite In 1-2 sentences answer one of the questions below:
What sort of things come to mind when you think of Chemistry?
How do you think Chemistry has improved our lives?

3. The Importance of Chemistry
Everything around us is chemistry: The air we breathe, the coins in our pocket, the material that makes up our electronic devices, the medicine in our medicine cabinets
Look around, it’s all chemistry, or matter!
Studying Chemistry is important, it allows us to solve many of the worlds problems, everything from environmental issues to new medicines that treat cancer and other ailments
Chemistry is defined as the science that deals with the materials of the universe (matter) and the changes that these materials undergo

4. What is Chemistry?
The science that deals with the materials of the universe (matter) and the changes that these materials undergo

5. Chemistry and the Scientific Method
Science and Chemistry is about solving problems
To solve problems, scientists use something called the scientific method
The scientific method is a systematic process that utilizes a series of inquiry based steps and observations about or natural world

6. What is the scientific method?
A systematic process that utilizes a series of inquiry based steps, observations, and measurements about or natural world

7. Steps in the Scientific Method
State the problem and make qualitative or quantitative observations
Qualitative observations involve a physical description (the quarter is shiny or lustrous)
Quantitative observations involve a quantity or measurement (the quarter weighs 15.5 grams)
15.5 grams

8. Steps in the Scientific Method
Formulate a hypothesis; a hypothesis is an idea or explanation based on observations
Perform experiments; an experiment is something we do to test the hypothesis
The data/information we gather during the experiment allows us to decide whether to accept or reject our hypothesis
Iterate or repeat experiments to confirm results

9. What steps makeup the scientific method?
State the problem and make qualitative (physical) and quantitative (measurement) observations
Formulate a hypothesis, an idea based on observations
Perform experiments that produce data and information allowing you to either accept or reject your hypothesis
If necessary, repeat experiment to confirm results

10. Hypotheses, Theory and Law
Recall that a Hypothesis is an idea based on observations that has yet to be proven
Once a hypothesis has been confirmed through repeated experiments that consistently arrive at the same conclusion, we can begin to develop a scientific theory
A scientific theory is an idea(s) or explanation for some phenomenon that is based on and supported by evidence through observation, experimentation, and reasoning
It is different from a hypothesis in that it is supported with experimental evidence
Theories attempt to explain our natural world and can be further refined through additional experiments

11. Hypotheses, Theory and Law
A scientific law is a descriptive generalization about how some aspect of the natural world behaves under stated circumstances
It is a readily observable fact about something and is often confirmed true by a mathematical expression such as E = mc2
Both laws and theories are supported by experiments and empirical data
However, a law seeks to describe a natural action under a given set of conditions, and a theory explains how and why something happens

12. Hypotheses, Theory and Law
For example, consider the Ideal Gas Law, PV = nRT
This mathematical expression describes and makes generalizations about the behavior of gas molecules in our natural world under a given set of conditions
On the other hand, consider the Big Bang Theory, it seeks to explain the origin of our universe through ideas that have been supported through scientific research studies and evidence
Both a scientific theory and law are accepted to be true by the scientific community

13. In science, what is the difference between a Hypothesis, Theory and Law?
A hypothesis is an idea based on observations that has yet to be proven
A theory is an idea(s) or explanation for some phenomenon that is supported by evidence through observation, experimentation, and reasoning
A law is a descriptive generalization about how some aspect of the natural world behaves under stated conditions
Both a theory and a law are supported by experiments

14. Experimental Design
In every experiment we have what are called variables
Variables may change or not change at all
A variable is any factor or condition such as temperature, volume, or mass that can change or remain constant in an experiment
An experiment has 3 kinds of variables: independent, dependent, and controlled.

15. What is a Variable?
Any factor or condition such as temperature, volume, or mass that can change or remain constant in an experiment
3 types: independent, dependent, or control

16. Independent, Dependent and Control Variables
In an experiment we have what are called variables
The independent variable is the variable that you (the person doing the experiment) change or manipulate in the experiment for a desired outcome or effect
It may be temperature, pressure, or the amount of chemical available
The dependent variable is the variable that changes as a result of the independent variable; and is the variable being tested in an experiment
Control variables are variables that are kept constant to improve the accuracy of your experiment

17. Independent, Dependent and Control Variables
Let’s say you want compare the cleaning effectiveness of chemical brands X and Y on their ability to remove grass stains on clothing
In this experiment, there are many variables that could effect the outcome of your experiment, the amount of cleaning chemical, the size of the stain, the type of clothing
The independent variable, the variable you manipulated in this case would be the type of cleaning chemical (X or Y)
The dependent variable would be how well each stain was removed and eliminated from the clothing (it is dependent on the independent variable)
Controlled variables consisted of equal amounts of cleaner, same types of clothing, and the same stain size,
For accuracy, these control variables remained constant throughout the experiment X Y

18. What is the difference between an independent, dependent, and control variable?
The independent variable is the variable that is changed or manipulated in the experiment for a desired outcome
The dependent variable is the variable that changes as a result of the independent variable; it is the variable being tested in an experiment
Control variables are variables that are kept constant to improve the accuracy of your experiment

19. Summary (you can always write your own summary)
Explain the science of Chemistry in your own words
Condense the scientific method into one sentence
Make a Venn diagram relates scientific law and scientific theory
Design a your own simple experiment and identify any independent variables, dependent variables, and control variables
Law
Theory
Different
Same