With these measurment,we can say that the Ph in the outside artificial puddle grow faster than the
ph in the inside artificial puddle.

The other measurement show that the temperature is also higher outside than inside.

-a higher temperature make micro-organism more active,an accelerate the decomposition of the lettuce.Thus,the Ph grow faster with the higher temperature.

-a higher temperature also make evaporation faster. The amount of water reduce,but the amount of acid stay the same,so the acid concentration grow up,and so the ph.

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Microscopy
How to use microscope ?

-Turn the nosepiece objective turret to choose the best objective lens.
Your microscope slide should be prepared with a coverslip or cover glass over the specimen. This will help to protect the objectives lenses if they touch the slide.

Now look throught the eyepiece and adjust the light and the diaphragm for the greatest amount of light.

Move the microscope slide around to put the image in the center of the field of view and readjust the light for the clearest image.

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How to mesure Turbidity ?

Turbidity is a mesure of  how much light is being absorbed by the water.

For intance:
if turbidity  is equal to 100 % , it means that no light can go through the water ; and if turbidity is equal to 0 % , the water is completely transparent.

We mesured the turbidity at two wavelengths :
– at 550 nm, when light is absorbed by detritus
– at 460 nm, when light is absorbed by clorophyll

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To take the temperature of our artificial puddle, we use a thermometer with a tip. We switch on the thermometer and we put the tip into the stagnant water. We wait for the stabilization of the temperature. Then we can read the number shown on the screen.

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pH is  the  measurement of the acidity or the alkalinity in the solution. If you want to take pH measurement, you must have a pH-meter and you must keep the sensor in a bottle of a KCl saturated solution to protect it.
Before using it, you must clean the sensor with deionized water before drying it.
You must put the sensor in a solution of pH=4, then in a solution of pH=7 to calibrate the pH-meter and having the right settings.
Finally, you have to put the sensor in the stagnant water and wait for the reading to stabilized to have your data.

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To mimic puddles, we placed a few pieces of lettuce in two crystallizers filled with water (pH= 7). It also could have been done using  grass. We placed one  crystallizer inside the biology laboratory and the other one outside, exposed to sunlight.

After 3 days, there were enough living organisms for us to begin the study (physical and biological mesurements)

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