2 What is the scientific method? It is a way in which scientists answer and solve problemsThe steps to solve a problem or question
3 Steps of the scientific method 1. State problem or question to be solved or answered2. Form a hypothesis3. Experiment to test hypothesis4. Collect data from experiment and observations5. Form a conclusion6. Communicate ideas and results
4 Use observations to form a question you would like to investigate You can use your senses to gather information._______________ observationYou can use tools to gather information called measurements_______________observationTools make accurate observations.Often you are asking a question about the relationship between thingsExample: The position of the light source and the size of the shadowQualitativeQuantitative
5 HypothesisA possible explanation that needs to be tested“If…….., then………. will happen.Form a hypothesis about the position of the light source on the object and the length of the object’s shadow.Hypotheses are NOT facts! Instead it is a possible way to answer a question.Many trials are needed before a hypothesis can be accepted as true.If the light source gets closer to the object, then the objects’ shadow will get…
6 Experiment When you carry out procedures to test your hypothesis Experiments begin by first examining all the variablesVariables are factors that can change in an experimentCan you name a few variables that could change in an experiment?Experiments should be designed so only one variable is changed!There are two types of variables: Independent variable and dependent variable
7 Independent Variable The variable that is changed in an experiment Example: Susan sets up an experiment to test whether the position of the light impacts the length of the shadow. In order to test this, she shines the light on a cereal box from six different positions. At each position, she measures the length of shadow the cereal box casts. What would be the independent variable? (Hint what is Susan changing?)The position of the light
8 Dependent VariableThe variable that is expected to change because of the independent variable.Example: Think about Susan’s experiment to test whether the position of the light impacts the length of the shadow. She shown the light on a cereal box from six different positions, and at each position, she measured the length of shadow the cereal box casts. What is the Dependent variable? (Hint: what is changing because of Susan’s independent variable?)The length of the shadow
9 Identify the Dependent and Independent Variables. Students conduct an experiment to test if studying leads to higher tests scores. What would be the independent variable (the thing that changes)? What would be the dependent variable (What is changing because of the independent variable)?Independent Variable: Time spent studyingDependent Variable: Test score
10 Identify the Independent and dependent variable A scientist conducts an experiment to test the theory that a vitamin could extend a person’s life-expectancyWhat would be the independent variable?What would be the dependent variable?Independent Variable: Taking VitaminsDependent Variable: Life-expectancy (How long you live)
11 Identify the independent and dependent variables. Students experiment to see how different amounts of sunlight impact how much plants grow.What would be the independent variable?What would be the dependent variable?Independent Variable: Amount of sunlightDependent Variable: Plant growth
12 Control Group and Experimental Group A control group is a group in a scientific experiment where no variables are changed.It is used to compare results against the a group where a variable is changed called an experimental group.Example- A student is testing to see if plants will grow without sunlight.Which would be the experimental group and which would be the control group?ExperimentalControl
13 What makes a good experiment: Control groupOne independent variableTesting the hypothesis many times (many trials)
14 Collecting and Interpreting Data Make observations and record them into a data table.Data tables can be for both quantitative and qualitative observations.Make a data table that would describe some qualitative observations of different types of rocksMake a data table that would describe some quantitative observations of different types of rocks.Graphs are useful way to view quantitative data because they reveal trends or patterns
18 Drawing ConclusionsAfter scientists interpret their data (with the help of a graph usually), they draw a conclusion about their hypothesis.Conclusions state whether or not the data supports the hypothesisMy hypothesis was correct because….My hypothesis was incorrect because…Should be supported by observations!!!
19 CommunicatingSharing ideas and conclusions about your experiment with others through writing and speakingScientists share the design of an experiment as well so others can repeat the experiment to check the resultsCommunicating information about discoveries often leads to new questions, new hypotheses, and new investigations.
20 Model Represents an object or system in science. Example: Globe of Earth
21 TheoryA well tested explanation for many observations and experimental results.Well tested and widely accepted by scientists.Example: Atomic theory- all substances are composed of tiny particles called atoms. This theory explains many observations: why water freezes or boils at certain temperature, and why water can dissolve many other materials
22 LawA statement that describes what scientists expect to happen every time under a particular set of conditionsExample- Law of Gravity “What goes up must come down.”A scientific law describes an observed pattern in nature without attempting to explain it.