Can air, water and soil be exhausted by human activities ?

Can ground water get polluted by sewage? How?

Can water be made to boil without heating?

In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature?

Take two concal flasks and paint one white and other black.Fill both with water. Place the conical flasks in direct sunlight for half an hour to one hour. Touch the conical flasks . Which one is hotter ? You could also measure the temperature of the water in the two conical flasks with a thermometer. Can you think of ways in which this finding could be used in your daily life ?