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Scientific Methods Steps scientists use to answer questions and solve problems.

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Presentation on theme: "Scientific Methods Steps scientists use to answer questions and solve problems."— Presentation transcript:


2 Scientific Methods Steps scientists use to answer questions and solve problems

3 Solving a Problem Ask Question (Problem) Gather Information State Hypothesis Design Experiment Make Observations Collect and Analyze Data Form Conclusions Retest (validate)

4 Solving a Problem

5 Ask a Question  How does fertilizer affect the growth rate of plants?  scientists notice something in their natural world  Example: Does fertilizer make plants grow taller?

6 Make Observations  Gathered using the 5 senses  Record what happens during the experiment in your lab notebook  Use black or blue ink  The information you write down is called data  Example: My neighbors’ plants are taller than my plants. He uses fertilizer and I do not.

7 State a Hypothesis  A suggested solution to the problem  Must be testable  Sometimes written as If…Then statement  Predicts an outcome  Example: If plants are grown using fertilizer, then they will grow taller.

8 Design an Experiment  A procedure to test the hypothesis  set up an experiment testing different amounts of fertilizer on plants & measuring the growth (height) of the plants  must contain variables and controls  may have many controlled factors  can only change one variable

9 Design an Experiment  Controls  factors that are kept constant  not being tested!  examples: amount of water, type of soil, amount of sunlight, type of fertilizer  act as a standard of comparison  should not effect the outcome of the experiment

10 Design an Experiment  Variables  2 types  1- dependent variable  what you measure in the experiment  unpredictable change: we don’t know how it will change until we do the experiment  graph on Y-axis height of plants  2- independent variable  manipulated variable  predictable change: it only changes because we chose how it would change  the more trials… the better  graph on X-axis amount of fertilizer The effect of _____________ on _____________ INDEPENDENT DEPENDENT The effect of _____________ on _____________ Amount of Fertilizer Height of Plants

11 Collect and Analyze Data  May be organized into charts, graphs, tables  2 types of data  Quantitative  Expressed mathematically  numbers  Qualitative  Descriptive nature  words, feelings

12 Analyze Data  What does your data show  Graphs  line graphs  graphing data that shows continuous change  bar graphs (or histograms)  graphing data that is in disconnected groups How’s a critter to choose?

13 Examples of experiments  What’s the favorite drink of students?  we set up an experiment surveying students and asking which is their favorite drink :  dependent variable (Y-axis)?  number of students  independent variable (X-axis)?  type of drink The effect of _____________ on _____________ Type of Drink How many students chose it

14 Which drink do you like best? type of drink number of students 1 2 3 4 5 6 CokePepsiwaterteaGatorade 0 drinknumber Coke1 Pepsi1 Water4 Iced tea4 Gatorade3 Red Bull? RB Bar graph!

15 How does elevation affect temperature? elevation temperature 5 10 15 20 25 30 05001000150020002500 0 elevation (feet above sea level) temp. (°C) 030 50025 100020 150015 200010 25005 1200 ft? 1818 Line graph! 1200

16 Form Conclusions  Answer to the hypothesis based on the data obtained during the experiment  Check for bias  In order to verify the results, experiments must be  Retested  valid!  Communicate results  Scientists publish work in journals

17 Any Questions??

18 Examples of experiments  How does exercise affect heart rate of 10th grade student?  we set up an experiment testing different lengths of time of exercise (minutes) on the heart rate of students:  dependent variable (Y-axis)?  heart rate  independent variable (X-axis)?  minutes of exercise The effect of _____________ on _____________ Exercise Heart Rate

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