Scientific method & Experimental Design GRADE 8 Science

Nareefa N. Bacchus Science September 6th, 2017 OBJECTIVE: To understand the scientific Method and Experimental Design

SCIENTIFIC METHOD The Scientific Method is a systematic way of obtaining and understanding answers to questions we may have. Steps to the Scientific Method: Observation and Research (Which leads to a Question). Hypothesis- This is a testable explanation for a question you may have. It shows the relationship between the cause and effect, and it follows the ”if…then” pattern. Experiment and Gathering of information Analyzing and Interpreting the information Conclusion (Either “Accepting” or Rejecting the Hypothesis).

SILLY WAY TO REMEMBER THE STEPS OF THE SCIENTIFIC METHOD: Owen Has Every AstonMartin Car Observation Hypothesis Experiment Analyze Conclusion

EXPERIMENTAL DESIGN Experimental design and the scientific method are intertwined. In order to have a well designed experiment, you must have a dependent variable, and independent variable, and a control.

Independent Variable The independent variable must be measureable. The independent variable is also referred to as the EXPERIMENTAL VARIABLE. In an experiment, an independent variable is a variable that either changes on its own, or you purposely change it. The experimenter can manipulate or change this variable.

Dependent Variable The dependent variable must be measureable. Changes in the independent variable may cause the dependent variable to change. Typically what the experimenter is looking for.

The goal of an experimental investigation is to determine how changes in an INDEPENDENT VARIABLE affects the DEPENDENT VARIABLE.

CONTROL In experiments there are usually two groups: 1. Testing Group 2. Control Group The testing group is the group on which things are done to  By definition, the control in an experiment is a sample that remains the same throughout the experiment and is not affected by the independent variable. https://www.youtube.com/watch?v=D3ZB2RTylR4

Why is it important for scientists to follow the Scientific Method when conducting experiments? It is important for scientists to follow the Scientific Method so that they are not bias. When Scientists create a hypothesis, they may sway the experiment to give them the result they desire based on their own personal ideals, morals, and belief. However, the scientific method is a system to minimize biases.

Why is it important for scientists to share their findings? Scientists communicate about their work because it allows for collaboration and replication of experiments. If I do an experiment or a survey in my area and someone else does the same elsewhere, if our results confirm each others', then we can use that as further support. If they contradict each other, then looking for reasons why can help further explain the phenomenon. 

Why is it important to repeat experiments? It is important to repeat experiment so as to prevent inaccurate data. For example, lets assume you are doing an experiment, but you got distracted and you made a mistake, but you don’t realize it. Then, the information you get form that experiment would be incorrect. Therefore, it is important to repeat experiments multiple times just in case you made mistakes the first time.

How does Science and Technology influence our life? Science and technology influence our lives in many different ways. Everything around us has been created or at least influenced by science and technology in some way. Below are a few of the things in which technology and science influence out day-to-day lives. 1. Medicine 2. Transport: Think of supercars, Formula 1, etc. Science and technology constantly influence each other. 3. Nature

Scientific Measurements Review and understand the Scientific Measurements on Page 17 of your textbook.

QUESTION 1: A gardener performs an experiment growing three types of plants in equal amounts of soil. Three different types of plants are used. Each plant is 10 centimeters tall at the beginning of the experiment. The three plants are given 4 milliliters of water every day for 20 days. The results of the experiment are shown on the graph.

Question 1: Which Plant was the tallest at the end of the 20 day period? Other than at the beginning of the experiment, on what day were plant 2 and plant 3 the same height? Which plant grew at the slowest rate from day 0 to day 5? During which time interval did plant 1 become taller than plant 3? The gardener repeated the experiment using identical conditions. Plant 1 grew the fastest. Suggest one change to the experimental design that would help the gardener decide which plant really grows fastest.

QUESTION 2 A student goes skateboarding a few times a week. The student notices that she can go faster while skating on some level surfaces than on others. She hypothesizes that speed has something to do with the surface she is skating on. The student wants to design an experiment to test this hypothesis.

Question 2: Identify the independent (manipulated) variable in the experiment. Identify the dependent (responding) variable in the experiment. Identify two factors that will need to be held constant in the experiment.

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THE END For Now…Lol Until I see you next Period.