"Parse Tree" <parsetree at hotmail.com> wrote:
>Item G11:
>The water level in a small aquarium reaches up to a mark A. After a large
>ice cube is dropped into the water, the cube floats and the water level
>rises to a new mark B. What will happen to the water level as the ice melts?
>Explain your reasoning.
>>I am actually curious as to what the answer to this question is. Will the
>volume of ice, which is greater than that of water offset the parts of the
>ice that are above water?
Go to
http://timss.bc.edu/timss1995i/Items.html
and you can download the test items yourself, with answers. You can also
find the other grade levels' items, and elsewhere on the site you can find
the 1999 testing results, as well as the preliminary information on the 2001
reading literacy comparison (the results have not yet been released, but the
methodology has).
http://timss.bc.edu/timss1995i/data_almanacs_95.html
has the detailed results by question and by country that I have been citing
in response to the nincompoop.
-----------------------------------
On G11, only Germany, Norway, and Slovenia had more than 25% of the kids get
that one entirely correct.
HOWEVER 28.1% of the Americans got partially correct codings (10, 11, and 19,
below, most of them coded 10), for a total of 33.3% that got the answer
partially or completely right, whether or not they explained it correctly.
This was comparable to Germany and Norway (around 35%) and ahead of Slovenia
and all of the other countries.
The coding key below explains the correct answer, BTW.
>Correct Response
>20 Same level. Response refers to the fact that the volume (or mass) of the water
>displaced by the ice is equal to the volume (or mass) of the water produced when
>the ice is melted (Archimedes' principle).
>Example: Level is the same because the ice displaces the same volume of
>water as when it melts.
>29 Other acceptable responses.
>Partial Response
>10 Same level. Incomplete or incorrect explanation.
>Examples: a) Ice and water has the same mass.
>b) Ice has less density than water.
>11 Same level. No explanation.
>19 Other partially correct responses.
>Incorrect Response
>70 Rising level, with or without explanation.
>71 Sinking level. The water has smaller volume/greater density/"molecules are
>closer together" than the ice OR the ice has greater volume/smaller
>density/"molecules are further apart" than the water.
>72 Sinking level. Because ice contains air.
>73 Sinking level. As the ice melts the mass decreases (or disappears).
>74 Sinking level. With other or without explanation.
>79 Other unacceptable responses.
>Nonresponse
>90 Crossed-out/erased, illegible, or impossible to interpret.
>99 BLANK
lojbab
