extras

Independent variable: 

-the length of time the water will be exposed to sunlight

Dependent variable:

-the amount of bacteria the water contains 

Controlled variable: 

-the amount of water in each zip blog bag

-the day of the experiment

-the water source that the water was taken from

Limitations:(from discussion)

-do not have an exact reading

-the climate in different countries differ-the result would not be the same as other countries
-the amount of sunlight on the day of the experiment