The Scientific Method Ms. Pettit

Step 1: Question Who? What? Where? Why? How? When? Sometimes called “The Problem”

Step 2: Hypothesis Prediction Educated guess Based on initial observations May be written as an If…then…: If the metal is combined with an acid then it will form a gas.

Step 3: Test the Hypothesis This involves DOING a CONTROLLED Experiment Gather Materials Design a detailed procedure Determine all the possible variables Be sure to include a control group Create data tables Make careful observations

Materials Equipment and Measuring WE OFTEN USE TOOLS WHY???

Writing a Procedure What are you going to do? List the Steps Pay attention to details like units Identify the Independent Variable, the Dependent Variable, the Control Group and the Constants

KEY COMPONENTS Independent Variable: The factor adjusted by the experimenter (one thing you are testing) Dependent Variable: The results of the one variable (what happened, measurements) Constants: The factors that are the same for all the lab set-ups (so only 1 thing is different) Control Group: Untreated group - comparison Experimental Group: Group that receives the variable, what you are testing happens to them

Make Observations What happened? Data “I saw” “I heard” Use tools Record units Put data in tables and charts

Step 4: Analyze the Results Graphs and statistics section of the lab Take the data and make it easy to understand in a picture Look for patterns and relationships

Step 5: Draw a Conclusion Results Hypothesis: Right or wrong? Question answered Create new hypothesis Improvements Repeat

Follow Up! Create Some way of reporting Presentations Display board Formal Report Posting to a website

LET’S PRACTICE Ask some questions that can be tested…

LET’S PRACTICE

An experiment was designed to test the effect of water with salt on rusting in iron. 100 pieces of iron were selected. Each piece of iron was the same size and mass. Each piece of iron was cleaned the same way prior to the experiment. 50 pieces of iron were placed in salt water for 2 weeks while the other 50 pieces of iron were placed in distilled water for 2 weeks. The water in both groups was the same temperature. The iron was checked for rust each day at the same time and in the same method. 1. water temperatureA. Constant 2. iron placed in distilled waterB. independent variable 3. salt added to the water in group 2C. dependent variable 4. iron piecesD. Control 5. appearance of rust* one answer above is used twice

LET’S PRACTICE