Presentation on theme: "5/9/11 Have out research ?s, answers and citations Objectives: 1.Determine the independent, dependent and control variables in an experiment. 2.Create."— Presentation transcript:
5/9/11 Have out research ?s, answers and citations Objectives: 1.Determine the independent, dependent and control variables in an experiment. 2.Create an informed, quantitative hypothesis for an experiment. Catalyst: 1. From the following hypotheses, determine the independent, dependent and a control variable. A. Flowers given more sunlight will grow taller. B. Tide cleans better than Gain. C. Whiter teeth makes people more attractive. 2. What does it mean for a variable to be quantitative? 3. In which of the experiments above were the dependent variables quantitative?
Science Fair Timeline This week (5/9-5/13): – Today (5/9): Determine variables and hypothesis – Tomorrow (5/10): Determine materials and procedure – 5/11: Create data table and plan type of graph for data – 5/12 & 5/13 return to acid and base-continue s.f. on own Next Week (5/16-5/20) – 5/16 & 5/17 In-class lab time – 5/18 data analysis and reflection – 5/19 & 5/20 Computer data analysis and graphing 5/23-5/27 – 5/23 & 5/24 PowerPoint creation (must be completed 5/24) – 5/25-5/27 PowerPoint presentations to class 5/31: School Science Fair for winners
5/10/11 Have out list of variables and hypothesis Objective: Write a detailed experimental procedure. Catalyst: What are key features of a well written experimental procedure? Homework: Complete material list and experimental procedures
What Makes a Good Experimental Procedure? Use this as a checklist! Includes a detailed list of materials Includes a description of all groups Includes a step-by-step, numbered list of procedures Describes how to change the independent variable Explains how to measure the dependent variable Describes how to keep control variables constant Specifies how many times you will repeat the experiment (at least 3) The ultimate test: Someone else can complete the experiment based on the procedure
A Good Materials List Is Very Specific A Bad Materials List 500 ml of de-ionized water Water Stopwatch with 0.1 sec accuracy Clock AA alkaline batteryBattery
Testing which toothpaste works better Get some people and have them try Crest and Aquafresh. See which works better. Whats wrong? – Materials not listed – Not detailed – Groups not described – Not step-by step – Does not describe how IV varies – Does not describe how DV measured – Does not mentions controls or how they are kept constant – Does not specify repetitions – No one could replicate this experiment
Better procedures List materials – Materials: Crest Pro-Health Whitening Gel Toothpaste - Fresh Clean Mint, Aquafresh White & Shine toothpaste, 10 Aquafresh Direct Toothbrushes, distilled water, egg timer Describe Groups/repetitions 1.Selected 10 Uplift High School Students. 2.Measure teeth whiteness using a standardized color scale, ranging from one to 10. 3.Pair students according to initial whiteness of teeth.
Describe how IV changes 2. Randomly assign one member of each pair was to use Crest or Aquafresh toothpaste for one week Describe controls 3. Instruct participants to brush 3 times a day for exactly 2 minutes using the aquafresh direct toothbrush, at 7:00 am, 12:00 pm and 7:00 pm. Describe how DV is measured 4. Re-measure tooth whiteness of each participant using the standardized scale. 5. Subtract before tooth whiteness from after tooth whiteness to determine increase in tooth whiteness.