INTRODUCTION TO SCIENCE & THE
SCIENTIFIC METHOD How to do an experiment
What is Science? The goal of science is to investigate and understand the natural world, to explain events, and to use those explanations to make useful predictions.
Science is an organized way of using evidence to learn about the natural world.
What is scientific inquiry?
Process scientists use to study the world and develop explanations based on evidence.
How is science done? Scientists collect and organize information in a careful, orderly way, looking for patterns and connections between events.
Scientists propose evidence that can be tested by examining evidence.
Scientists make an observation by using their senses to gather information.
Qualitative Quantitative Observations A description Tells how many
Color Texture yellow balloon Size blue sky puffy cloud Tells how many Total amount Length Mass objects 2 stars temp: 1500 C
What do scientists do? Scientists use the scientific method which is a series of steps used to solve a problem or answer a question.
What Are Scientific Methods?
Order of the steps can vary- not always the same *Can use all steps or just some- it depends on the investigation! *Steps can be repeated
Scientific Method Steps
The problem Form a hypothesis Design a controlled experiment Procedure Collect and record data Analyze the data State your conclusion
The Problem Start with a problem that can be solved scientifically.
What makes a boat float? The problem is always written as a question. Why? How? What? How would you find the density of an object? The problem is measurable. Research What do you know? What do you need?
A scientific explanation, an educated guess, or an answer to a question
Based on prior knowledge or observations that can be tested in an experiment Written in the form If …. then …. because If a boat can float then its density is less than water because it does not sink. Form a hypothesis
Prediction vs Hypothesis
Predictions ARE NOT hypotheses! A hypothesis explains what did happen. A prediction is made before you test a hypothesis. *It is what you think will happen *It states a cause and effect When predictions are shown to be true, the hypothesis is supported.
Testing the Hypothesis
Can test a hypothesis by doing an experiment Factor anything in an experiment that can influence the outcome
Design a controlled experiment
The factors in an experiment that can be changed are called variables. Some example of variables would be : changing the temperature, the amount of light present, time, concentration of solutions used. 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.
between a controlled group with an experimental group.
An experiment is based on the comparison between a controlled group with an experimental group. These two groups are identical except for one factor. The control group serves as the comparison. It is the same as the experiment group, except that the one variable that is being tested is removed. The experimental group shows the effect of the variable that is being tested.
Describe the control group. Describe the experimental group.
PRACTICE 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.
The factor being tested
Identify the variables The factor being tested
Independent & Dependent
The changes that occur because of the experiment It can be observed and measured Is the data that is collected Comes after “then” in the hypothesis What is being tested or changed Only have ONE Comes after “If” in the hypothesis Control – the standard to which the outcome of the test is compared.
Procedure Make a plan. Test the hypothesis by changing one variable.
Collect materials and tools. Follow directions. Gather information through observation, making measurements.
Collect and record data
Use senses to make any observations Collect measurable information Record information on a data table Does the data support or not support the hypothesis? Collect and record data
IMPORTANT REMINDER!! Repeat, repeat, repeat!
*The more times an experiment is done, the more data there is to support or disprove the hypothesis
Interpret or explain the data with graphs or pictures
Analyze the data Interpret or explain the data with graphs or pictures
Conclusion A logical answer that addresses the original problem, analyzes the data and determines whether or not the data supports the hypothesis. Experiments must be repeated over and over. When repeated, the results should always be the same before a valid conclusion can be reached.
Practice Problem Paper airplanes
Practice Problem The problem
Some paper airplanes fly farther than others. What type of paper makes the best airplane?
Practice Problem The problem
Some paper airplanes fly farther than others. What type of paper makes the best airplane? Form a hypothesis If a paper airplane is made using construction paper then it will not travel so far because construction paper has more mass.
IDENTIFY THE VARIABLES
Practice Problem The problem Some paper airplanes fly farther than others. What type of paper makes the best airplane? FORM A HYPOTHESIS If a paper airplane is made using construction paper then it will not travel so far because construction paper has more mass. IDENTIFY THE VARIABLES Independent: construction paper Dependent: distance plane traveled Control: force thrown
QUESTIONS What is the importance of the control?
What is the difference between the independent and the dependent variables in an experiment? What is the importance of the control?
QUESTIONS Why is it so important that a scientist accurately describes the procedure used in the experiment? In a “controlled experiment”, why must all of the variables, except one, be kept constant throughout the experiment?
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