Ch. 1 & 2 The Nature of Science & Measurement

1. Ch. 1 & 2 The Nature of Science & Measurement • What is Science? Ask yourself this question. • Asking a question >>> One explanation >>> New information • Scientific Theories – attempt to explain a pattern observed repeatedly. The must be supported by facts. • Scientific Laws – rule defined over time. Must be observed repeatedly and accepted by science as being fact.

2. Branches of Science • Earth Science – physics, chemistry & life science on Earth or space • Chemistry – concepts of matter • Physics – matter & energy in motion • Life Science or Biology – study of organisms

3. Scientific Method – Fig. 8 pg. 12 • Question a. Hypothesis (define) b. variables – difference between dependent and independent. Talk about later c. Develop a plan – list your steps. 2. Test a. Set up a control and experimental group. b. conduct experiment & record data. 3. Analyze a. develop a chart, graph, or table. b. compare data with hypothesis - Is it supported or refuted 4. Conclude a. Re-evaluate hypothesis b. Explain your theory based on observations and data.

4. Experiments – a way to investigate the question • Testing the variables or factors of experiment • Types of variables • Independent – variable that is changed in an experiment • Dependent – variable that is changes due to the experiment usually caused by the result of the independent variable. • Constants – variables that aren’t changed or don’t change during the experiment. They remain the same.

5. Precision and Accuracy • Precision – how close is the measurements to each other. • Accuracy – how close is the measurements to the actual or accepted value. • Take a look at pg. 46 on precision vs. accuracy with a target.

6. Significant Digits – number of digits that truly reflects the precision of a number • Rules • Digits other than zero are always significant. • Final zeros after a decimal point (23.4300) are significant. • Zeros between any other digits (608.032) are significant. • Initial zeros (0.045) are NOT significant. • Zeros in a whole number (54,300) may or not be significant. It depends if one shows the decimal point (54,300.0) YES.

7. Rules of Rounding Measurements • Basic rule of five; round numbers down if less than five and round numbers up if five or greater. • Examples: Round the following number to the nearest tenth place • 69.36 7.45 10.378 184.134 • Digits to the right of the digit being rounded to a deleted if they are also to the right of a decimal. If they are to the left of a decimal, they are changed to zeros. • Examples:

8. SI Units – The International System • A system that is used by all the scientific world as a standard measuring system. Except U.S. • It is a basic system of tens: KHDMDCM • Tables 1 and 2 on pg. 50

9. Measurements • Length – A distance between to points • Weight – gravitational pull (w=mxg) • Mass – amount of matter in an object • Area – (3.14)r2 • Volume –HxLxW • Density – d=m/v • Time – seconds • Temperature – K

10. Drawings, Tables, & Graphs – a method to illustrate details of scientific information • Drawings – must detailed illustration of data; it shows the picture which can show layers, depth, color, multiple dimensions. • Tables – away to display info. in either rows and/or columns to make it easier to read. • Graphs – used to collect, organize, and summarize data.

11. Types of Graphs: • Line Graphs – shows the relationship between two variables; both variables must number data on x and y axis. X-axis which is the horizontal axis and Y-axis which is the vertical axis. • Bar Graphs – uses rectangular blocks (bars) to show the relationships among variables. One variable must be a variable while the other variable does not need to be. • Circle or Pie Graphs – shows the relationship by fractions or percentage with in a circle.