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Tim and Moby’s Experiment. Why did Tim and Moby want to set up an experiment? What were they testing? Throughout the experiment, what did each plant have or receive that was exactly the same? Throughout the experiment, what did each plant receive that was varied or different?.
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Tim and Moby’s Experiment. Why did Tim and Moby want to set up an experiment? What were they testing? Throughout the experiment, what did each plant have or receive that was exactly the same? Throughout the experiment, what did each plant receive that was varied or different?
Why couldn’t Moby and Tim have set up their experiment like this to test if watering a plant too much would cause it to die? A Flower A Cactus A Tree A weed Plant A Plant B Plant C Plant D Never watered Watered everyday Watered 3 times/week Watered once/week
A Controlled Experiment • Only tests one variable at a time (Variable= factor in an experiment) • Control– Sometimes called constants. What the scientist keeps constant • Most experiments have a control group. This group does not receive the manipulated variable. The control group is used as a standard of comparison. • What were Tim and Moby’s controls? Same type of plant, the same type of pot, the same amount of soil, the same amount of sunlight
A Controlled Experiment • Manipulated Variable- Sometimes called the independent variable. What the scientist deliberately changes (Should only have one – this is usually what is being tested) • What was Tim and Moby’s manipulated variable? The amount of water
A Controlled Experiment • Responding Variable – sometimes called the dependent variable. changes in response to the manipulated variable • What was Tim and Moby’s responding variable? Plant Growth
Redi’s Experiment on Spontaneous Generation Section 1-2 OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass gauze covering that keeps flies away from meat Manipulated Variables: Responding Variable: whether maggots appear Maggots appear No maggots appear Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. CONCLUSION: Go to Section:
E. Hypothesis: a possible explanation or answer to a scientific question • Experiments are performed to test a hypothesis F. Theory: a hypothesis that has been supported by many experiments