Metrics Review Units = Base (Meters, Liters, and Grams) Symbols = g, L, m, mL, km Prefixes = kilo, hecto, deka, deci, centi, & milli What do the prefixes mean? Kilo = 1000 (thousand) - Deci = .1 (tenths) Hecto = 100 (hundred) -Centi = .01 (hundredths) Deka = 10 (ten) -Milli = .001 (thousandths)

Warm Up What is a model? Name several types of models. What models have you used?

What is a Model? Representation of object or system. Explains how something works or describes its structure. Makes predictions or explains observations.

Skeleton (what is a limitation of a skeletal model?) Physical Models Toy car Skeleton (what is a limitation of a skeletal model?)

Made up of numbers Equations Other forms of data Punnett Squares Mathematical Models Made up of numbers Equations Other forms of data Punnett Squares

Conceptual Models Represent systems or ideas Compares familiar things with unfamiliar things Comparisons help explain unfamiliar things (classification)

Benefits of Models Represents things that are very small or very large Represents things that are complicated or no longer exist Dinosaurs

Scientific Theories Scientific Theories Scientific Laws An explanation that ties together many related facts, related facts, observations, and tested hypotheses. Conceptual model Helps to organize scientific thinking Widely accepted Evolution Summary of experimental results and observations. What will happen in a specific situation. Newton’s Laws of Physics http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/80007.htm

Let’s Review http://my.hrw.com/sh2/sh07_10/student/flash/virtual_investigations/hst/liv/hst_liv_vi.html

Scientists Belong to a World Community Scientists interact with society War, weapons Famine, greater food production Disease, cure

Society Affects Scientific Research Technology Computer Internet Space Science Iron Man Cars Cell Phones Benefits/Risks

Society’s Values Shape Scientific Ethics What are ethics A system which deals with the distinction between right and wrong. These rules help protect scientists, themselves, society, and the natural world. Give me an example Investigate Ethics Informed Consent

Variables Independent Dependent Manipulated What was changed Cause Testing how salt affects the freezing temperature of water. Change the amount of salt used. Responding How did it respond to the change? Effect The temperature at which the water freezes depends on the amount of salt used. http://www.worsleyschool.net/science/files/saltandfreezing/ofwater.html

Controls Experimental Group Control Group Testing the effect of a new fertilizer Plant seeds are different so we are going to plant a number of seeds in pots that contain the new fertilizer. Each seed becomes a trial A set of trials with the same value of the independent variable. How do we know if the new fertilizer works? Use a control for comparison. Add the currently used fertilizer to some pots, then put seeds in them. The control and experimental group are treated equally except for the fertilizer. Any changes is because of the fertilizer used.