COT-3-REFRACTOMETER-1.ppt AGRI-FISHERY ARTS

COT- AGRI-FISHERY ARTS ( AQUACULTURE)

1. CLASSROOM RULES RAISE HAND IF YOU WANT TO SPEAK LISTEN TO THE TEACHER/CLASSMATE WHEN THEY ARE TALKING. PARTICIPATE DURING YOUR ACTIVITY. DO NOT MAKE UNECESSARY NOISE.

2. WATER PARAMETERS Dissolve Oxygen pH Turbidity Temperature Salinity

3. PARTS AND ITS FUNCTION OF SALINITY HAND HELD REFRACTOMETER

4. OBJECTIVES: Define a refractometer; Identify parts of a refractometer and its functions. show the manipulation of the refractometer correctly.

5. Refractometer – is a devise use to measure salt content in pond water. Hand Held Salinity Refractometer is an instrument designed easily to measure the salt content of the water. In Shrimp grow-out operation or production Refractometer is very important used in daily monitoring of salinity needed by cultured species.

6. Parts of the Refractometer and its Function 2. 3. 4. 5. 6.

7. Parts/Function Prism – place for water sample Daylight Diffuser Cover- to cover water sample Calibration Screw/Calibration Screw Cap- adjustable screw to read test sample Rubber Grip – rubber handle to prevent from sliding Eyepiece - look through the scale of the sampled water Focus Adjustment – to adjust the focus until scale can be seen clearly

8. Parts of the Refractometer and its Function A traditional handheld refractometer consists of a measuring Prism that you place a few drops of the liquid to be examined on with a Daylight Diffuser Cover to cover the sample. It has an Eye piece that you look through as you hold the Rubber Grip up to a light source to obtain a reading. Calibration screw- There is an adjustable screw behind the stage. This moves the bimetallic strip and so   allows the refractometer to be correctly calibrated before it is used to test a sample. Focus adjustment - can be adjust the focus by twist- ing the eyepiece until the scale can be seen clearly.

9. PROCEDURE HOW TO USE THE REFRACTOMETER ADJUSTMENT OF SCALE The calibration of the refractometer is done through placing two to three drops of distilled water on the prism before closing the cover plate and start reading. If the refractometer reads zero, the calibration screw should be turned the scale until it reads '0'and hence the calibration is complete. INSTRUCTION FOR USE Open the daylight plate and apply one or two drops of a sample solutions onto the prism surface. Close the daylight plate gently. Then the sample solution spreads like a thin film in between the daylight plate and the prism. Hold the hand refractometer with a hand facing the daylight plate upward, direct it toward the light and observe the field of view through the eyepiece. When the field of view is not clear, adjust it by turning the cross stripe portion of the eyepiece either clockwise or counterclockwise. The upper field of the view appears in blue and the lower field of view appears in white. Read the scale across the scale. The read value is the Salinity %of the seawater

10. EVALUATION DIRECTION: Identify the different parts of the refractometer and its function. 5. ________ 2. ________ 1 . ________ 3 . ________ 4 . ________ 6 . ________

11. ASSIGNMENT Draw and level parts of a Secchi Disk ?