Tides

For Gymnastics class daily we have to cross bridge on river Tapi. Children are use to observe river and keen to notice water level goes up and down. Day after full moon day while passing from bridge Ash noticed water level was low. She asked why? I told her there are two tides everyday but on full moon day and new moon day you can see difference clearly in water level. Now, Why on full moon day and new moon day?

She was having knowledge about how day and night and how moon rotates around earth but not knowing how full moon and new moon occurs. Started experiment with globe and source of light. First experiment how day and night occurs by projecting her as Earth first and then using globe. Then using mirror as moon explains how full moon and new moon day occurs and how different phases of moon. Still her question was unanswered. And because it is difficult to explain her gravitational forces of sun and moon (though tried to explain with magnets), centrifugal force of earth and other reasons behind tides on full moon and new moon days. Answer in short ,because positions of sun and moon on these two particular days are so which causes tides. Though her curiosity half satisfied she was happy knowing something new about full moon and new moon day and enjoyed long discussion about how earth born and how life came into existence. Now we are going to take record of water level each day.