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Experiment : Testing for the Presence of Living Organisms in the Soil
Name: Class:
School: Date:

Results

Test Tube

Observation
Control  
A  
B  
C  
D  

Conclusion

Had the bromothymol blue in the control tube changed colour? Explain your answer.



What is this tube used for?



Compare any colour changes for the other four tubes.



What do these results indicate to you about the numbers of living organisms in the different soil samples?



Can you think of an explanation for this?