1. First, you have to collect different samples of water from different watercourses.
2. Half-fill plastic bottles to using water samples from streams and close them well.
3. Shake the closed bottle for approximately 1/2 minute. Then open a bottle and smell at once.
4. Determine the intensity of smell with Ball’s odour intensity scale. Try to also determine the type of smell.
|BALL||INTENSITY OF ODOR||DESCRIPTION|
|1||very weak||odor is detected only by professional|
|2||weak||odor is detected if we are warned|
|3||perceptible||odor is easily detected|
|4||distinct, prominent||odor draws attention|
|5||very strong||odor drives away|