1. Unit 2: Scientific Understanding

2. I. Characteristics of Scientific Knowledge. a.Empirical evidence: this is data and observations that have been collected through the Scientific process. b.Logical reasoning: Scientists do their best to look logically at their data to reach a conclusion i. Two different reasoning’s 1. Objective reasoning: based on evidence 2. Subjective reasoning: based on opinion c. Pseudoscience : a set of beliefs that make us of science but the conclusions and predictions are not based in scientific evidence i. Example: Astrology

3. II. Models and Systems a.Model: representation of a process that cannot be observed directly b.System: group of parts that work together to carry out a function i. Input: the material or energy that goes into the system ii. Process: action or series of actions that happen within the system iii. Output: the material or energy that comes out of the system iv. Feedback: output that changes the system

4. II. Models and System Cont. v. Example: Eating an apple With your table partner, think about the system of eating and where these different parts of a system play in eating an apple. input? Process? Output? Feedback?

5. III. Theories and Laws a.A theory is a well-tested explanation with a wide range of observations and experimental results. b.A scientific law is a statement that explains what scientists expect to happen every time under particular conditions. i. Law of Gravity: What goes up must come down ii. Newton’s First Law: An object in motion will stay in motion and an object at rest will stay at rest unless met with an outside force.

6. III. Theories and Laws Cont. c. Theories can change over time i. As new evidence occurs, theories can change or evolve ii. As technology improves, our ability to observe the natural world improves, which can change the theories.

7. IV. Scientific Laws to know a.Newton’s First Law of Motion: An object at rest will remain at rest unless acted on by an outside force. An object in motion will remain in motion unless acted upon by an outside force. b.Newton’s Second Law of Motion: Acceleration is produced when a force acts on a mass. (force = mass x acceleration) c.Newton’s Third Law of Motion: For every action there is an equal and opposite re-action. d.First Law of Thermodynamics: Energy cannot be created or destroyed e.Second Law of Thermodynamics: Heat can only go to objects that are cooler

8. Warm Up #3 1. If my car is going at an acceleration rate of 23.6 m/s and I know the mass of my car is 134 grams. What is the force that is being applied to my car? 2. If I know that to move a rock you must exert 13 Newton’s of force to accelerate the rock at a rate of 1.6 m/s, what is the mass of this rock? 3. If a pulley has a 15.4 g box hanging from it and the pulley is exerting a force of 7 Newton’s, what is the box’s acceleration as it is moving up the pulley system? 4. The candle warmer in the picture is an example of a simple system. What is the Input, process, and output of this system?