Chapter 1 – Intro to Science Section 1 – The Nature of Science

What do you think of when you hear the term “scientist” What do you think of when you hear the term “scientist”? Maybe you imagine a guy in a lab coat, or a person holding up tests tubes of strange substances. Scientist don’t all fit the general stereotype, but all scientists do perform the same types of tasks. Scientists try to describe and explain the universe using basic rules and laws. Scientists use the scientific method in order to do this. Math also plays a huge role in science. Every field of science uses math in some way!

Section 2 – The Way Science Works

The Scientific Method begins with an observation The Scientific Method begins with an observation. A scientist may see something happen, then wonder about WHY that event happened. The next step is the hypothesis. A hypothesis is a “guess” about why something happens. After a hypothesis is made, it needs to be tested. Scientists experiment to test hypotheses. After the experiment is complete, a conclusion about the hypothesis can be made. The conclusion does not always agree with the hypothesis. When this happens, the scientist must come up with a new hypothesis and repeat the process..

An easy way to remember the scientific process is the acronym “OHEC”. O – Observation H – Hypothesis E – Experiment C – Conclusion Scientists are constantly using the scientific process to test new theories.

Understanding Graphs We use graphs in our everyday lives. They are a quick way to show a lot of information. Weather data, sports statistics, population, and voter response are only a few things that graphs can be used to show.

There are 3 basic types of graphs: Line, Circle or Pie, and Bar. Each type of graph has an advantage to showing certain kinds of data. Line graphs are used to show a constant change. Line graphs are placed on a grid with an X and Y axis. Time is often shown on the X axis, and the dependent variable (the thing you are measuring) is put on the Y axis.

Bar graphs are used for comparison. When you need to compare several similar types of data, a bar graph is best.

Circle graphs (or pie charts) are used to show the parts of a whole. Percents are shown on circle graphs, and all of the data on the graph will add up to 100%.

The SI units of measurement: Scientists rely on the SI system when they take measurements. This system is used by scientists around the world. SI stands for “system international”. Many of the SI units come from the metric system…a way of measuring things based on 10’s.

Here are the common units in the metric system: Length – meters. Volume – liters. Mass – grams. Time – seconds. The basic units of the metric system can be altered using prefixes. When a prefix is added to a basic unit, that unit becomes larger or smaller.

Here are the prefixes that are used with metric units, from smallest to largest. Milli (m) - .001 Centi (c) - .01 Deci (d) - .1 Standard Units – 1 (meter, gram, liter, etc) Deka (da) – 10 Hecto (h) – 100 Kilo (k) – 1000 For example, a kilometer is 1000 meters. A millimeter is .001 meters, a hectometer is 100 meters, and a centimeter is .01 meters.

Scientific Notation Many times, scientists have to work with numbers that are very big, or very small. Because of this, a way to rewrite very large or very small numbers was created. Definition: scientific notation – a method of expressing a quantity as a number times 10 to the appropriate power. The definition of scientific notation may sound confusing, but once you begin writing numbers in scientific notation, it will make more sense.

Examples of Scientific Notation: Look at the amount of numbers behind the 1 in the original number, then compare it to the exponent number above 10…they are the same! It may look easy with regular numbers, but what about more complicated numbers? Let’s try 380, 3,800, and 3,8000… 380 = 3.8 x 102 3,800 = 3.8 x 103 38,000 = 3.8 x 104 Easy stuff once you get the hang of it! Let’s try some examples (CPS).

Now lets look at very small numbers in scientific notation: Lets say you have the numbers .1, .01, and .001. How would they be expressed in scientific notation? The exponents become negative when dealing with decimal numbers. .1 = 1 x 10-1 .01 = 1 x 10-2 .001 = 1 x 10-3 The exponent is the number of 0s behind the decimal +1. So, in .1 there are no 0s, so the exponent is 1. (0 + 1)

Examples: .0009 = 9 x 10-4 .00056 = 5.6 x 10-4 .0941 = 9.41 x 10-2 EASY!