The Scientific Method A Way to Solve a Problem

What is the Scientific Method? It is the steps someone takes to identify a question, develop a hypothesis, design and carry out steps or procedures to test the hypothesis, and document observations and findings to share with someone else. In other words, it’s a way to solve a problem.

The steps of the Scientific Method are: State the problem Gather Information Form a Hypothesis Test the Hypothesis Record and Analyze Data State the Conclusion Repeat the Work

Mnemonic sentence Forming a sentence by using the first letter from a list of terms in assisting or intended to assist memory

Mnemonic sentence

Scientist have to take the time to think logically when they are investigating a question or problem. They break things down into many steps that make sense.

Scientists develop a question, gather information and form a hypothesis.

What is a Hypothesis? A Hypothesis is a possible answer to a question A Hypothesis is a proposed solution to the problem. A Hypothesis is your best guess based on research. A Hypothesis must be testable.

Forming a Hypothesis A Hypothesis is based upon information and observations that can be tested. Hypothesis are often stated as if-and-then statements. A hypothesis needs to be testable. A Hypothesis can be proven false, but can never be proven absolutely true. This allows other people the ability to verify the results, and leaves the chance to find better explanations as our understanding grows. If plants are fertilized, then they will grow taller

The next step scientists take is to create and conduct an experiment to test their hypothesis.

Testing the Hypothesis In order to test a hypothesis, you must perform an experiment. In any experiment, it is important to keep everything the same except for the item you are testing. Two groups are usually tested.

Experimental & Controlled Group The Experimental group gets the item that is being tested. The test group. Test only ONE condition at a time, everything else same as control. The Controlled group – used as a standard for comparison. Gets everything that the experimental group received except the tested item. All controlled experiments must have a control. Controlled group Experimental group

Independent Variable What the investigator manipulates, the particular treatment or condition the investigator is most interested in the effects of. The item that is being tested. The independent variable will always be in the experimental group The effects of steroids

Dependent Variable (Data) What is measured or observed, the “data” collected in the experiment. Any changes in this variable depend on the change made to the independent variable. There are two types of data: Quantitative- of, relating to, or involving the measurement of quantity or amount, (can be expressed as a number) Qualitative- relating to or involving comparisons based on qualities  (descriptive)

Dependent Variable (Data) In the steroid experiment 25 rats were given anabolic steroids and 25 were given a placebo, the number of aggressive encounters were recorded for each group. What are the: control and experimental group. The independent and dependent variables

Independent Variable Steroids Dependent Variable Aggressive Behavior No Drug (placebo) Independent Variable Steroids Dependent Variable Aggressive Behavior

A key to experiments is observing what happens and writing it down. Gathering information or data and documenting it so it is readable and makes sense to others is really important.

Record and Analyzing Data in Experiments Collect Data. Choose a graph or chart that best fits your experiment. Graph may be a bar graph, line graph or pie chart.

Purpose of Using Graphs or Chart To show and compare changes. To show and compare relationships. To Bring facts to life

Advantages of Using graphs Quick way for the audience to visualize what you are saying. Emphasizes main point. Proves a point, they can see and hear it. More interesting than just talk or print.

Disadvantages Time consuming to make. (Not true if you use technology available now) Technical ( audience knowledge to interpret or understand). Costly- depending on the medium used (poster board, transfer letters, color prints, size, etc).

A Bar Graph Called a Histogram. Numerical dimensions are shown in bars or varying lengths. Shows comparisons. Multiple comparisons are possible. Two items being compared do not need to affect each other. A fast way to show big differences.

A Line Graph Line graphs can be used to show how something changes over time Shows the relationship between two variables . Shows the effect of an independent variable on the dependent variable. Shows how things rise and fall in a line graph

Understanding Axis on a line graph The variables being compared go on two axis of the graph. The independent variable always goes on the horizontal axis, called the x-axis. The dependent variable always goes on the vertical axis, the y-axis.

X Axis vs Y Axis Usually, the x-axis has numbers for the time period .                                                             Usually, the x-axis has numbers for the time period y-axis has numbers for what is being measured.

Labeling Axis & Recording Data

A Pie Chart Shows percentages effectively. Shows how a part relates to the whole. Easy to grasp. Label larger portions in the circle, smaller outside with leader lines.

Once a scientist completes an experiment, they often repeat it to see if they get the same findings and results. This is really what we call verification, or checking things out to make sure everything was valid and will happen again and again.

Scientists share their experiments and findings with others. Because they share their experiments and findings, scientists can learn from each other and often use someone else’s experiences to help them with what they are studying or doing.

Creating Graphs Use the data on each trial from the number of pill bugs and construct a line graph. Use the data on the total number of pill bugs and construct a bar graph. Use the data on the average number of pill bugs and construct a pie chart.