Parts of an Experiment (Activity)

Parts of an Experiment (Activity)

​Parts of an Experiment

​After posing questions, scientists use further observations to make inferences, or logical interpretations based on what is already known. Inference can lead to a hypothesis that can be tested in ways that support or reject it. 

​​Whenever possible ...

a hypothesis should be tested by an experiment in which only one variable is changed.

• All other variables should be kept unchanged, or controlled. This type of experiment is called a controlled experiment.

• It is important to control variables because if several variables are changed in the experiment, you can’t tell which variable is responsible for any results they observe.

Poll

A zoologist wants to know if feeding mice a vitamin supplement will make them grow larger. She feeds 50 mice their regular food, and she feeds 50 other mice food with vitamins. She measures the weight of the mice at the start and end of the experiment.

• Dependent Variable

  Type of Food

• Dependent Variable

  Weight of Mouse

Poll

A zoologist wants to know if feeding mice a vitamin supplement will make them grow larger. She feeds 50 mice their regular food, and she feeds 50 other mice food with vitamins. She measures the weight of the mice at the start and end of the experiment.

• Independent Variable

  Type of Food

• Independent Variable

  Weight of Mouse

Poll

A botanist is curious to know if a carnivorous plant grows better with a diet of live flies or dead flies. The plant normally eats live flies. He puts three plants in a terrarium with live flies, and he puts three other plants in a terrarium and feeds the plants dead flies by hand. He measures the plants at the start and end of the experiment.

• Dependent Variable

  Condition of the flies (live or dead)

• Dependent Variable

  Weight of the plant at the end of the experiment

Poll

A botanist is curious to know if a carnivorous plant grows better with a diet of live flies or dead flies. The plant normally eats live flies. He puts three plants in a terrarium with live flies, and he puts three other plants in a terrarium and feeds the plants dead flies by hand. He measures the plants at the start and end of the experiment.

• Independent Variable

  Condition of the flies (live or dead)

• Independent Variable

  Weight of the plant at the end of the experiment

Poll

A student is interested in the effect of the temperature of water in her aquarium on the activity level of her fish. She divides her aquarium water and fish into three aquariums, one which is maintained at room temperature (about 21.5°C), one of which is heated to 28°C, and one of which is 13°C.  At 6 p.m. each day she watches the fish for half an hour and records her observations about their activity.

• Dependent Variable

  Temperature in the aquarium

• Dependent Variable

  Level of fish activity

Poll

A student is interested in the effect of the temperature of water in her aquarium on the activity level of her fish. She divides her aquarium water and fish into three aquariums, one which is maintained at room temperature (about 21.5°C), one of which is heated to 28°C, and one of which is 13°C.  At 6 p.m. each day she watches the fish for half an hour and records her observations about their activity.

• Independent Variable

  Temperature in the aquarium

• independent VariableVariable

  Level of fish activity

​Now complete the follow up activity...

​Post to google classroom for a grade