2 Systematic Approach Six Steps State the problem/question Gather information on the problemForm a hypothesisIf…then…because…Perform experimentsRecord and analyze dataState Conclusion
3 State the Problem/Questions Develop a clear statement defining the problemMake sure your problem is narrowed/specific enough
4 Gather Information Write down all information you already know Do research in books on the topic you are investigatingAsk experts on the subject you are researchingIf you find an answer to your problem/question you do not need to move on
5 Form a HypothesisSuggest a possible solution to your questionMay be right or wrongShould be based on the researchShould be in the correct format:If (independent variable), then (dependent variable, because (what you will change)
6 Perform ExperimentsDevelop a test to prove or disprove your hypothesisMust be run multiple timesMust have only 1 independent variable (the factor being testedMust include 2 setupsExperimental setupControl setup
7 Experimental SetupPart of the experiment containing the independent variableIndependent variable – part of the experiment you are changingMust have only 1 independent variable to ensure the results are accurateExample:Plant with dirt, water, sunlight, 25oC and fertilizer (this is the independent variable if you are testing the effects of fertilizer)
8 Control SetupSetup exactly the same as the experimental setup, except it does not include the variableExample:Plant with same amount of dirt, same kind of dirt, same water, same temperature, and same sunlight, DOES NOT have any fertilizer
9 Variables Independent Variable Dependent Variable 1 thing you are testing1 thing you change between experimentsi.e. amount of fertilizer, brand of fertilizer or amount of waterDependent VariableThing that changes because of the independent variableYou do not controli.e. Number of leaves on the plant, height the plant grows, amount of fruit it produces
10 Record and Analyze Data Recording DataAny observations and measurementsMust write every observation downMust be consistent in when you are checking your experiments and recording the resultsCan be recorded as tables or chartsAnalyzing DataMust be looked at to determine patternsCan make into graphsMust Complete all necessary mathematical calculationsAnswer any questions from the lab
11 Observations Qualitative Observations Quantitative Observations Observations describing the experimenti.e. Color, smell, touch, taste, lookQuantitative ObservationsObservations with numerical values and unitsi.e. Height in cm, length in m, number of leaves
12 State a Conclusion Paragraph (minimum of 5 sentences) Decide if you hypothesis is correct or incorrectState what proved or disproved your hypothesisUse data in your descriptionState errors you may have madeState future tests to be run
13 Writing HypothesesA hypothesis is a tentative statement that proposes a possible explanation to some phenomenon or event. A useful hypothesis is a testable statement which may include a prediction.
14 When Are Hypotheses Used? The key word is testable. That is, you will perform a test of how two variables might be related. This is when you are doing a real experiment. You are testing variables.Any laboratory procedure you follow without a hypothesis is really not an experiment. It is just an exercise or demonstration of what is already known.
15 How Are Hypotheses Written? Chocolate may cause pimples.Salt in soil may affect plant growth.Plant growth may be affected by the color of the light.Bacterial growth may be affected by temperature.All of these are not examples of hypotheses because they use the tentative word "may“. Using the word may does not suggest how you would go about proving it.If we say "Trees will change color when it gets cold“ we are making a prediction. Or if we write, "Ultraviolet light causes skin cancer" could be a conclusion.One way to prevent making such easy mistakes is to formalize the form of the hypothesis.
16 Notice that these statements contain the words, if and then. Formalized Hypotheses example:If skin cancer is related to ultraviolet light , then people with a high exposure to UV light will have a higher frequency of skin cancer.If leaf color change is related to temperature , then exposing plants to low temperatures will result in changes in leaf color.Notice that these statements contain the words, if and then.If you always ask yourself that if one thing is related to another, then you should be able to test it.
17 Formalized hypotheses contain variables. 3 TYPES OF VARIABLES1. Independent (Manipulated) Variable2. Dependent (Responding) Variable3. Controlled VariableThe independent variable is the one you, the "scientist" control and the dependent variable is the one that you observe and/or measure the results.
18 INDEPENDENT (MANIPULATED) VARIABLE • The variable that can be changedduring an experiment• The variable that may cause achange in the dependent variable
19 DEPENDENT (RESPONDING) VARIABLE •The factor that is being measuredin an experiment•The variable that may changebecause of the independent variable
20 CONTROL VARIABLE(CONSTANT) •Variable that stays the same duringan experiment•Variable that is controlled by thescientist•Variable that is not allowed tochange
21 Daily Assignment:Rewrite the first four hypotheses using the formalized style.Single underline the dependent variable and double underline the independent variable in the If clause of each hypothesis. When you are done, write one more original hypothesis of your own using this form.
22 Independent Variable- Red Dependent Variable – Blue Control- Green Chocolate my cause pimples.2. Salt in soil may affect plant growth.3. Plant growth may be affected by the color of the light.4. Bacterial growth may be affected by temperature.If 5 ounces of chocolate is eaten for three straight days, then pimples will appear.If
23 Independent Variable- Red Dependent Variable – Blue Control- Green Chocolate my cause pimples.2. Salt in soil may affect plant growth.3. Plant growth may be affected by the color of the light.4. Bacterial growth may be affected by temperature.If 5 ounces of chocolate is eaten three days in a row, then pimples will appear.If 2 cups of salt is added to the soil, then the plant will not grow.