Q&A - PSLE Science

[Studious Alien]

Ready2WORK:

balu_priya:

Please help.


1)which one of the following statements Best describes a characteristic of living things?
1.living things cannot survive in the absent air.

Living things may have the ability to give birth to young ones.alive
Living things move from place to place in search of food.
Living things can live in the presence of large amount of water.



2.two ice cubes were stacked and a pushing force exerted from the top. After one minute , both ice cubes could be lifted off the surface by just
Holding the top of ice cube.

The process that resulted in the ice cubes 'sticking'together is/are ...........
1.melting
2.freezing
3.melting and freezing
4.evaporation and freezing

Q1) 1
Animals and plants cannot live in the absence of air, so Option 1 is correct. Option 2 only applies to mammals, not all living things. Option 3 only applies to animals, which can move from place of place by themselves. Lastly, Option 4 only applies to aquatic animals and plants. Therefore, answer is 1 as it best describes living things.
Q2) 3
The ice cubes melted, turning into liquid state, then due to it losing heat to the ice cubes, it froze again, joining the two ice cubes together. So answer is 3.

I do not understand your explanation for Q2.What is the 'it' in the first line? Please explain in a more detailed way. Thanks.

Regards,
Studious Alien

[verykiasumummy]

Studious Alien:

Ready2WORK:

[quote=\"balu_priya\"]Please help.


1)which one of the following statements Best describes a characteristic of living things?
1.living things cannot survive in the absent air.

Living things may have the ability to give birth to young ones.alive
Living things move from place to place in search of food.
Living things can live in the presence of large amount of water.



2.two ice cubes were stacked and a pushing force exerted from the top. After one minute , both ice cubes could be lifted off the surface by just
Holding the top of ice cube.

The process that resulted in the ice cubes 'sticking'together is/are ...........
1.melting
2.freezing
3.melting and freezing
4.evaporation and freezing

Q1) 1
Animals and plants cannot live in the absence of air, so Option 1 is correct. Option 2 only applies to mammals, not all living things. Option 3 only applies to animals, which can move from place of place by themselves. Lastly, Option 4 only applies to aquatic animals and plants. Therefore, answer is 1 as it best describes living things.
Q2) 3
The ice cubes melted, turning into liquid state, then due to it losing heat to the ice cubes, it froze again, joining the two ice cubes together. So answer is 3.

I do not understand your explanation for Q2.What is the 'it' in the first line? Please explain in a more detailed way. Thanks.

Regards,
Studious Alien[/quote]maybe i can help.

both the ice cubes melted at their contact surfaces, hence changes its state to liquid. due to some of the liquid on the surface of both ice cubes losing heat to the ice cubes again, it changes its state back to solid, hence joining the two ice cubes together.

[verykiasumummy]

pecalis:

Fertilisation occurs when the nucleus of sperm fuses with the nucleus of egg. Child's answer is correct, not just fusing (or fusion?) of sperm and egg but the fusing of both nuclei.

This is my understanding from my son's Sc notes.

yes u are right, dunno what i was thinking just now.. but my ds did mention something like \"the combination of the nuclei from both parents contains characteristics...\" and the teacher mark it wrong. i couldnt rmb the exact reason that the teacher gave, but my ds was taught to just say, \"the egg cell from mother and sperm cell from father fuse during fertilisation and pass their characteristics to their offspring.\"

hope it helps.

[Studious Alien]

verykiasumummy:

maybe i can help.

both the ice cubes melted at their contact surfaces, hence changes its state to liquid. due to some of the liquid on the surface of both ice cubes losing heat to the ice cubes again, it changes its state back to solid, hence joining the two ice cubes together.

Thank you very much verykiasumummy.

[verykiasumummy]

Studious Alien:

verykiasumummy:

maybe i can help.

both the ice cubes melted at their contact surfaces, hence changes its state to liquid. due to some of the liquid on the surface of both ice cubes losing heat to the ice cubes again, it changes its state back to solid, hence joining the two ice cubes together.

Thank you very much verykiasumummy.

no thks... was just trying to help...

[NY1969]

Can someone ans this question in a scientific way:-


A metal rod is partially is submerged into an ice water. After sometimes, why is the other end of the rod becomes cool also?

[G Tan]

NY1969:

Can someone ans this question in a scientific way:-


A metal rod is partially is submerged into an ice water. After sometimes, why is the other end of the rod becomes cool also?

question is not clear.. what you mean by the othr end?

[ruohoo97]

NY1969:

Can someone ans this question in a scientific way:-


A metal rod is partially is submerged into an ice water. After sometimes, why is the other end of the rod becomes cool also?

Because metal is good conductor of heat. It transmits heat more quickly so you will feel the other end getting cold too. Note here, the feeling of cold reflects the difference of temperature.

[NY1969]

Thanks. So the answer shld be…as metal is a good conductor of heat, the metal rod loses heat quickly to the surroundings and hence the other end of rod will be cooled eventually. Is this explanation ok?

[verykiasumummy]

NY1969:

Can someone ans this question in a scientific way:-


A metal rod is partially is submerged into an ice water. After sometimes, why is the other end of the rod becomes cool also?

Metal is a good conductor of heat, so the part that is submerged will lose its heat to the ice water quickly. And since heat travels from a hotter place to a colder place, the other end of the metal will also lose heat to the ice, causing it to be cold eventually.