scientific method and the controlled experiment. scientific method: the steps scientist use in an...

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Scientific Method and the Controlled Experiment

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Page 1: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

Scientific Methodand the

Controlled Experiment

Page 2: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

Scientific Method: the steps scientist use in an

investigation Observation Question Hypothesis Experiment Data analysis Conclusion Communication

Page 3: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

The Steps do not have to go in a certain order.

Follow the arrows on the diagram.

Notice different ways the process can take place.

Page 4: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

An Observation is something you notice with your senses.

Page 5: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

An Example of an Observation:

Every time my dog eats grass, he throws up.

Page 6: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

Curious people have questions about their observation. Does the grass make the dog throw up? Or maybe the dog feels sick and the grass

makes him feel better. If I ate grass would it make me throw up? How does grass make a dog throw up? Why does the dog eat grass, if it makes

him throw up?

Page 7: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

Hypothesis: a possible answer to a question Example of a

Hypothesis: It is possible that

dogs eat grass because they need some green plants in their diet.

Page 8: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

A good hypothesis can be tested with an experiment In a controlled

experiment, one factor is changed to observe the effect on another factor while all other factors are kept constant.

Page 9: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

An Example of a Controlled Experiment: Ten dogs of the same breed and age are fed

the same amount of dog food each day. Five of the dogs eat dog food containing

vegetables and the other five eat dog food that is made of meat only.

All dogs are allowed outside in the grass for the same length of time each day.

All dogs are observed to see if they eat grass.

Page 10: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

A variable is a factor that may change in an experiment.

There are two variables in a controlled experiment:

The independent variable

And the dependent variable

Page 11: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

The independent variable is changed on purpose by the scientist. What is the

independent variable in the dog food experiment?

Vegetables in the dog food was the factor that was different in the two groups of dogs.

Page 12: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

The Dependent Variable is measured or observed by the scientist to see if it was affected by the experiment. What was the

dependent variable in the dog food experiment?

Eating grass was measured or observed by the scientist to see if there was an affect on this behavior.

Page 13: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

The constants in the experiment are kept the same so only one variable could affect the results of the experiment.

Can you list the constants in the dog food experiment?

Breed of the dog Age of dog Amount of dog food Amount of time in

the grass

Page 14: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

To infer, is to draw a conclusion based on the results of the experiment.

The results of the experiment are analyzed.

The hypothesis is either accepted or rejected.

Then a conclusion can be made.

Page 15: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

If there was no difference in the grass eating habits of the two groups of dog….

The hypothesis would be rejected and

the scientist might infer that a dog’s diet does not affect grass eating.

Page 16: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

If the dogs that were on a diet that included vegetables ate less grass than the other dogs……. The hypothesis

would be accepted. The scientist might

infer that dogs eat grass because they need some plant material in their diet.

Page 17: Scientific Method and the Controlled Experiment. Scientific Method: the steps scientist use in an investigation Observation Question Hypothesis Experiment

Communication

Scientists share their findings with each other by publishing papers that describe their work.