 |
|
|
|
|
|
|
|
 |
|
||||||
 |
 |
 |
|
||||
 |
 |
 |
 |
 |
|
||
 |
|
||||||
 |
 |
 |
 |
|
|||
 |
|
||||||
 |
|
||||||
|
|
|
|
 |
 |
|
|
 |
|
||
 |
 |
|
|
 |
|
||
 |
|
||
 |
|
||
 |
|
||
 |
|
||
 |
 |
|
|
 |
|
||
 |
|
||
 |
|
||
 |
|
||
 |
|
||
 |
 |
 |
|
 |
|
||
 |
|
||
 |
|
||
Joseph Priestley's experiment1 Draw a diagram that shows you how Priestley set up his first experiment.
Priestley's second experimentIn another experiment, Priestley burned a candle in a sealed jar. He then placed a plant in the jar which contained air with no oxygen. The plant survived. Then Priestley placed a mouse in the jar that had the plant in it. The mouse did not suffocate. 2 What are the important points from the passage above?
3 Draw a diagram to show the information in the passage called 'Experiment 2'.
Comparing Priestley's experimentsHow were Priestley's experiments similar? How were they different? Complete the following table to compare them. 4 For each experiment, put a tick beside each statement that is true and a cross beside each statement that is not true.
A, B and C are all things that Priestley did in his experiments. They are steps in his method. D is what happened. It is part of his results. To learn something new from Experiment 2, you need to compare it with Experiment 1. There is only one thing that Priestley did differently in his two experiments. This is called a fair test, or a controlled experiment. It means that you can see the effect on the results of changing, or varying, one thing. Controlled experiments are very important in science. Priestley's experimentsThe results could depend on a change made by the candle so he burned the candle in both experiments. The results could depend on putting the mouse into the jar so he did this in both experiments. Making these variables the same in both experiment is called controlling them, or making them constant. The only variable that was different was using the plant. It is the only thing that changed that could have altered the results. And the results did change. The plant made the difference between the mouse living and dying. 5 Together, do Experiment 1 and Experiment 2 make a controlled experiment? Why or why not?
6 What variable is Priestley testing in his experiments?
7 Can you think of a variable in Priestley's experiments that does not need to be controlled because it would not alter his results? What is it?
|
|||||||||||||||||||||||||||||||||||||||||
 |
Lesson 7 - Photosynthesis |
||||||||||||||||||||||||||||||||||||||||
