Scientific Method

Problem or Question Research Hypothesis Procedure Observations Data Conclusion

Problem The problem is the QUESTION that you want answered. Ex: What paper towels absorb better? How often should you water the plant for the best growth? How many drops of water will fit on a penny? How many glasses of water would it take to fill up a tea pitcher?

Research To research a problem, you need to gather information. Information can come from: Online sources Books and other printed material Your brain Other people

_________ A possible explanation for observations that relate to a scientific question Must be testable by observation or experiment It is a Scientific “Guess” Example: I think that if I water the plant everyday, then it will grow taller than if I water it once a week.

You use all five of these to gather information Observation Uses all five senses Sight Hearing Touch Smell Taste You use all five of these to gather information

Data Observations and measurements recorded during an experiment

Trick to remember Variables: Factors that can CHANGE during an experiment 3 Types of Variables Controlling Independent Dependent Trick to remember Variables: DRY MIX

Controlled Variable The variable that stays the SAME 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 Variable The variable that the scientist CHANGES Manipulated variable 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 Variable The variable that the scientist Measures Responding variable 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.

Designing a Controlled Experiment A controlled experiment works with one variable at a time. If several variables were changed at the same time, the scientist would not know which variable was responsible for the observed results. A experiment is based on the comparison between a controlled group with an experimental group. These two groups are identical except for one factor. The controlled group serves as the comparison. It is the same as the experiment group, except that the one variable that is being tested is removed.

Example: In order to test the effectiveness of a new vaccine, 50 volunteers are selected and divided into two groups. One group will be the control group and the other will be the experimental group. Both groups are given a pill to take that is identical in size, shape, color and texture. Even though the volunteers are given identical looking pills, the control group will not actually receive the vaccine. Describe the control group.   Describe the experimental group. What variables are kept constant? What variable is being changed? This group will receive the vaccine. The size, shape, color, and texture of the pill. Whether or not the pill contains the vaccine.

There are two types of data: Quantitative data are: numbers and are obtained by counting or measuring. Qualitative data are: descriptions and involve characteristics that cannot be counted.

Recording and Analyzing Results 1. The data that has been collected must be organized and analyzed to determine whether the data are reliable. 2. Does the data support or not support the hypothesis?

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

Drawing Conclusions The evidence from the experiment is used to determine if the hypothesis is proven or disproven. Experiments must be repeated over and over. When repeated, the results should always be the same before a valid conclusion can be reached.

Compare Hypothesis to the Data How to begin…. Conclusion Compare Hypothesis to the Data How to begin…. According to my data, my hypothesis was right or wrong because…. I think this happened because….If I were to do this experiment again I would…..

Forming a Theory Theory: A theory may be formed after the hypothesis has been tested many times and is supported by much evidence. Theory: A broad and comprehensive statement of what is thought to be true. A theory is supported by considerable evidence.

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

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)