Physics and Chemistry

[beligu]

why sometimes full moon not appear at cloudless night and why in some months and not others?

why filtration to seperate sand and salt show salt not seperated?

 

 

 

[swansont]

The cycle/phase of the moon isn't tied to whether there are clouds.

[TonyMcC]

why filtration to seperate sand and salt show salt not seperated?

 

The very first experiment I did in school physics was separating salt from sand. We added enough warm water to completely dissolve the salt. we then filtered out the salt solution and then heated the solution until all the water had evaporated. It worked quite well although the wet sand would have been left a bit salty and the dry salt wasn't pristine - presumably because a little very fine sand got through the filter paper. I felt the experiment was successful and so I don't understand your question.

Edited September 17, 2011 by TonyMcC

[rktpro]

why sometimes full moon not appear at cloudless night and why in some months and not others?

why filtration to seperate sand and salt show salt not seperated?

 

 

 

A full moon is often thought of as an event of a full night's duration.

This is somewhat misleading, as the Moon seen from Earth is continuously becoming larger or smaller (though much too slowly to notice with the naked eye). Its absolute maximum size occurs at the moment expansion has stopped, and when graphed, its tangent slope is zero. For any given location, about half of these absolute maximum full moons will be potentially visible, as the other half occur during the day, when the full moon is below the horizon. [Wikipedia]

 

Salt is not separated simple because it gets dissolved in water and its molecules become more small, smaller than the pores on the filter paper and therefore, they pass.