## pavankumartgpk 2 years ago I am just not able to understand this ice in the water question.If an ice cube is floating on water,when it melts apparently the water level stays the same.But doesn't the volume decrease?Because when ice melts it doesn't completely cover the hole it created since it doesnt give as much water as water is denser.

1. UnkleRhaukus

can you phrase that as a question

2. pavankumartgpk

Why does water level stay the same when the ice cube floating in water melts?

3. Mashy

aha interesting question!!!.. let me answer it this way i ll use drawing!

4. UnkleRhaukus

|dw:1357977517632:dw|

5. pavankumartgpk

Okay but now when the submerged part melts the water we get from that doesnt completely cover the volume right?

6. Mashy

|dw:1357977591413:dw| in the two drawings.. the extra water volume is equivalent to how much MASS is.. cause density remains the same.. fine when ice floats.. the bouyant force is exactly equal to the weight of the ice... and the bouyant force = weight of water displaced.. hence the shaded portion of water has the same mass as the ice.. volume =- mass(ice)/density(water) when the ice melts... it becomes water... but it has the same mass as it was when it was ice.. (it has to be.. mass can't disappear when things change state).. hence the volume of that portion (shaded in 3rd diagram) = mass(ice)/density(water) ... (why density of water??.. cause now the ice has become water.. ).. hence you see in both cases the additional volume (shaded portion is the same)

7. Mashy

i put the negative sign by mistake! :-/

8. pavankumartgpk

Ok ill try to understand that.Sec

9. pavankumartgpk

Okay yeah,Got it thanx!

10. Mashy

lets see if you got it.. what would happen if ice was floating on MERCURY!? .. (which is way denser than water?).. after the ice would melt.. would the final level be more or less or same?

11. Mashy

And there are additional question i like you to think about?? what happens to the level of water.. when anchor from boat is throw into water?

12. pavankumartgpk

hmm lets see,now volume would increase.Because initially the volume would be lesser than after melting as volume of water after melting would be lesser than before.Correct?

13. pavankumartgpk

Sorry I meant density of water after melting would be lesser than mercury

14. Mashy

no that doesn't matter.. don't think about the fact that ice takes up less volume than water!!...

15. Mashy

but yes.. since density of water is lesser than mercury.. the level of water would be way way higher!!.. :)

16. pavankumartgpk

Yeah now when the anchor is thrown in water the water level would go down as it displaces more water when in boat right?

17. Mashy

precisely!!..

18. Mashy

i have nothing more to teach you *tears* :D

19. pavankumartgpk

:D Thanx a lot man.Was thinking over it for 2 hours.Finally got it

20. Mashy

no problem ;-)!