Experimental Components

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Experiment to test hypothesis*overall question*

Control Experiment- This experiment includes what you are comparing to. You either remove the independent variable or test what you have always done in the past.

*At the end of this experiment you MEASURE the dependent variable which is the result.

Constants- Parts of the experiment that have to

be kept the same for both experiments.

Must include both experiments below

Independent Variable Experiment-This experiment includes the thing that you are curious about, what you are testing.

*At the end of this experiment you MEASURE the dependent variable which is the result.

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This experiment also includesThis experiment also includes

Let’s break it down……….

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I have identified a problem with my tomato plants this past summer. They are growing very small tomatoes. I am curious, if I give them plant food will they grow larger tomatoes?

Here is my hypothesis-If I use plant food in my tomtoe plants water they will grow tomtoes twice as big as the plants that received just plain water

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Identify variables, control and constants

Independent variable- what is being tested is_____________(this is what the experimenter is deciding to test)

Control- what you are comparing to is _______________

Dependent variable- what you measure or the result is the _________________ Constants- all other parts of your experiments that must be kept the same for both experiments. Some examples are ____________________________________

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Identify variables, control and constants

Independent variable- what is being tested is the plant food

Control- what you are comparing to is no plant food

Dependent variable- what you measure or the result is the weight of tomatoes Constants- all other parts of your experiments that must be the same for both experiments. Some examples are amount of sunlight, amount of water, type of tomato plant, and growth time

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Independent Variable Experiment-• 10 ml of plant food dissolvedin water every week

• Plant beefsteak tomato seeds

• Full sun for 8 hours a day

• Use water from hose every day for 1 minute

• Growing time 70 days

Control Variable Experiment-• Plant beefsteak tomato seeds

• Full sun for 8 hours a day

• Use water from hose every day for 1 minute

• Growing time 70 days

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You would then measure the weight of the tomatoes (dependent variable) from both plants.

You would compare the weight of the tomatoes from the plant that received plant food to the weight of tomatoes from plant that did not receive plant food. This data would help you form a conclusion whether plant food helps grow larger tomatoes.

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Practice example- A teacher has the following question. She wonders if students use a calendar on their cell phones to record their homework will the percentage of homework turned in on time increase? She designs an experiment.

What is the independent variable?

What is the dependent variable?

What is the control?

Name three constants in this experiment.