The Scientific Method

6 Main Steps The series of steps that scientists use to answer questions and solve problems. You may use all of the steps or just some of the steps. The goal of the scientific method is to come up with reliable answers and solutions.

#1 Make an observation Look at the world around you and NOTICE something! Then, ask a QUESTION about what you see: What Why How When

#2 Form a Hypothesis Educated answer Testable. Stated in an IF – THEN format Example: How does acid rain affect plant growth? IF a plant encounters acid rain, THEN it will grow at a slower rate than a plant that encounters unaffected water.

#3 Test your Hypothesis Experiment Observe Record Data VERY CONTROLLED

#4 Analyze the results Decide if your hypothesis was correct or incorrect

#5 Draw Conclusions Hypothesis correct? move on Hypothesis incorrect? Try again. Ask more questions, check and change the experiment.

#6 Communicate Results Share your findings! Science builds more science Scientists love to prove each other wrong or confirm findings.

Scientific Method in Action The Scientific Method is not a straight line of steps. It contains loops which may be repeated over and over while others may be deleted and not necessary. In science, it is ok to be WRONG, a good experiment answers questions and finds answers- it may lead to other questions that need to be answered.

Scientific Law A statement that describes what scientists expect to happen EVERY time under a particular set of conditions. Example: Law of gravity …what goes up will come down…(happens every time)

Scientific Theory A well-tested idea that explains and connects a wide range of observations. Can be changed because of new evidence Example: My theory is that everyone in this class will get an A+ on their first test

Parts of a Science Experiment

Question Question= Observation! It must be specifically measureable and testable

Hypothesis Educated answer to the question Measurable IF-THEN Statement

Independent/Manipulated Dependent/Responding Variables 3 Types of Variables Control Independent/Manipulated Dependent/Responding

Control/Constant Variable Stays the same in every step Improves reliability – allows for a “fair test” Have as many as possible Example: You have two plants that are both in the same pot, with the same amount of soil, the same amount of seeds and have the same amount of water. You place one in front of the window and the other in a closet. After two weeks you measure to see the growth of each of the plants.

Independent/Manipulated Variable What are we changing or watching differently? x-axis on a graph. Example: You have two plants that are both in the same pot, with the same amount of soil, the same amount of seeds and have the same amount of water. You place one in front of the window and the other in a closet. After two weeks you measure to see the growth of each of the plants.

Dependent/responding variable What are we looking for? What are the results? What happened? What can we measure? affected by the change in the independent variable y-axis on a graph. Example: You have two plants that are both in the same pot, with the same amount of soil, the same amount of seeds and have the same amount of water. You place one in front of the window and the other in a closet. After two weeks you measure to see the growth of each of the plants.

Results There are many different ways to organize the data into your results Bar Graph Data Table Line Graph Circle Graph

VARIABLE PRACTICE W/S

Bar Graphs A bar graph displays discrete data in separate columns. Advantages Visually strong Can easily compare two or three data sets Disadvantages Graph categories can be reordered to emphasize certain effects

Line Graph A line graph plots continuous data as points and then joins them with a line. Multiple data sets can be graphed together, but a key must be used. Independent variable on the x-axis Dependent variable on the y-axis Advantages Can compare multiple continuous data sets easily Interim data can be inferred from graph line Disadvantages Use only with continuous data

Pie chart A pie chart displays data as a percentage of the whole. Each pie section should have a label and percentage. Advantages Visually appealing Shows percent of total for each category Disadvantages No exact numerical data Hard to compare 2 data sets "Other" category can be a problem Best for 3 to 7 categories

Observations and Data Qualitative data: description of results of experiment. Tell what it looks like. The solution boiled. Quantitative data: numerical data collected during the experiment. (May be expressed in a table and graph.) The temperature of the solution was 112° F.

Paper Airplane Experiment Question Hypothesis Controls Independent Variable Dependent Variable Results: Which type of graph? Graph title X-axis Y-axis Labels