Science begins with observation An observation is a
�Science begins with observation �An observation is a fact that is collected with the senses �An inference is a conclusion based on observations
Make 1 observation about this picture: ___________ Make 1 inference about this picture: ____________
�The scientific method involves a series of steps used to investigate a scientific problem. �PROBLEM �HYPOTHESIS �EXPERIMENT �DATA �CONCLUSION http: //www. mghs. sa. edu. au/Internet/Faculties/Science/Year 8/Pics/scientific. Method. gif
�To determine… �A question or problem that can be solved through experimentation § flickr. com Ex. To determine the effect of sunlight on plant growth.
�A hypothesis is a statement that expresses the expected answer to the problem. �Must be measureable. �If… then… statement § If plants receive 12 hours of sunlight, then they will grow the tallest.
� If you use anti bacterial hand cleanser, then there will be _____ bacteria. � If you exercise, then your heart rate will ________. � If carbon dioxide is present, then plants will grow ______. (*Hint: do not use better) Johnny wants to test the effect of different brands of dog food on allergy symptoms. He wants to see if no grain food will reduce the amount his dog itches. Write a hypothesis: ___________________________________
• Control group �The group without the tested factor �The control is exposed to the same conditions as the experimental group (constants) �The control serves as the standard for comparison �Placebo: • Experimental group �The group with the tested factor
Control No sunlight 4 hours 1 hour 5 hours 2 hours 6 hours 3 hours 7 hours
ü Tests the effect of a single variable Independent variable – the factor that “I” am testing Ex. ____________ • Dependent variable – the data collected as a result of the experiment. Ex. ________ • “The Effect of the independent on the dependent. ” Constants - Factors that are kept the same in both groups Ex. _________________
ü Large sample size ü Repeated with same results ü Peer Reviewed
�Collect and analyze results �Must be quantitative (measurable) �Organized in graphs, tables, and charts
Title the table: “ The Effect of X on Y. ” Column headings include the independent and dependent variables Column headings need to indicate units of measurement Sunlight Exposure (hours) 0 1 2 3 4 5 6 7 8 Plant Height (cm) 0. 0 0. 2 0. 5 2. 4 3. 7 5. 9 7. 2 8. 5 9. 2
10 9 Plant Height (cm) 8 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 Average Sunlight Exposure (hours) 7 8
� Graphs must have a title � Label each axis and include units � Number axis with equal increments Ex. 0 2 4 6 8 Ex. 0. 25. 5 � Spread out the graph (use more than half) � Independent variable on the x axis � Dependent variable on the y axis *Use a pencil for graphs
� What �As � Did was the effect of x on y? sunlight increases, the plant height increases. you support your hypothesis? � What can you infer from the data?
�An explanation supported from experimentation �Can be modified with new information
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