Truth is the way things are.
We base truth on a set of facts and our understanding of those facts. A good scientist must be ready to accept new facts as they are discovered and modify what is "true" in light of these facts. Even though science in school is usually taught in classes that are limited to a certain area, such as chemistry or physics, science is science, no matter what topic is involved. Science is being done whenever the scientific method is used.
Pure science is the gathering of information that adds to the body of human knowledge. Pure science is not directly concerned with the practicle use and application of the information.
Applied science, also known as technology, is the practicle use of scientific information.
The physical sciences are studies of matter and energy.
- Chemistry is the study of the structure and properties of matter.
- Physics is the study of the relationships between matter and energy.
The Scientific Method is an organized process of problem solving.
Planning An Experiment
Scientific theory - a generally accepted explanation of a concept or a broad explaination of a natural phenomena.
Example: The Big Bang Theory
Scientific law - a description of a natural phenomena that does not vary.
Example: The Law of Gravity
Can a scientific "truth" change? Just ask a Pluto
Science involves communication:
Everything scientists write is an argument, from a memo, to a journal publication, to a grant proposal--each is a document written to convince.
An ability to argue clearly and convincingly is essential. Today's professional, scientist or not, must have presentation skills of all types from writing, to speaking, to preparing effective electronic posters for meetings.
Lab Safety, everyone Is responsible!
Lack of pre-lab preparation is the main threat to safety in our lab. If you and your group are unprepared, you will be unsure of yourself, waste time, and have a good chance of making a mistake that leads to a problem.
When experiments are performed there are almost always some observations where questions like "how fast", "how far", or "how much" must be answered. The only way to answer these questions is through measuring.
Because of this, numbers in science will always have "units". These units are just as important as the numbers when communicating observations. Never write a number without its units.
A "standard" is something that is used as a comparison for measuring. Two things are important for any standard:
- A standard must be available for everyone to use when checking measurements.
- A standard should be something in nature that is the same all over the earth.
- A standard must never vary.
The International System of Measurement is the set of standards used in all sciences.
Unit Conversion Tables
SI Base Units
- Length - meter
- Mass - kilogram
- Temperature - oC
- Amount - mole
- Time - second
Derived Units are combinations of base units.
- Area - length squared
- Volume - length cubed
1 ml = 1 cm3
1 liter - 1 dm3
- Density - mass / volume
DH2O = 1 g/cm3
English System vs SI System
- mega - 1,000,000
- kilo - 1,000
- hecto - 100
- deca - 10
- base unit - 1
- deci - 0.1
- centi - 0.01
- milli - 0.001
- micro - 0.000001
- These "ballpark" relationships are close enough for every-day conversion.
- 1 yard ≅ 0.9 meter
- 1 mile ≅ 1.5 kilometer
- 1 inch ≅ 2.5 centimeter
- 1 pound ≅ 0.5 kilogram
- 1 quart ≅ 1 liter
Graphing makes trends in data easier to see.
Dimensional Analysis is the most important mathematical process in science.
Units in science are just as important as numbers. Dimensional analysis carries units through all calculations. Whatever mathematical operation is done with the numbers is also done with the units. When the final units match the desired units, the problem has been solved correctly.
Dimensional analysis is set up like this:
The key to dimensional analysis is the correct use of conversion factors to change one unit to another. A conversion factor is a fraction whose numerator and denominator are the same quantity expressed in different units.
5 examples of conversion factors:
First sample problem - with one unit to convert.
Convert 1 year into seconds.
TIP: Cancel the units as you go. Once all units have been canceled except the desired units, pick up your calculator:
Second sample problem - with two units to convert.
- Beginning with the given number, multiply all numbers across the top from left to right.
- Without hitting the equal button, divide by all the numbers across the bottom from right to left.
- Finally, hit the equal button one time to get the final numerical answer.
Convert 65 miles per hour into meters per second.
(TIP: only one unit can be converted at a time.)