Tutor Niedino: Pri Science Questions and Concepts

[atutor2001]

elkniwt:

Hi,


Qn just says germination. I really think teacher should not mark her wrong. dd felt that she is being wronged for being specific. [Like to ask the teachers in the forum, is it wrong to write oxygen?]

I agree that writing air is good enough, but the reason teacher gives her for marking it wrong is that carbon dioxide is also needed for germination... ??

I am/was not a teacher. However, if question only mentioned \"germination\", then your dd's answer is definitely correct. In fact oxygen is a more accurate answer than air because oxygen is that particular element inside \"air\" that is needed for germination.

If we put air as the answer, the assumption made is that it is normal air with oxygen content of about 20% (acceptable in primary school). If the air that the seeds were exposed to has very very low % of oxygen, (say high up in Mount Everest) the seeds may not germinate.

PS
Ask the teacher whether will the seed germinate if placed under 100% oxygen with warmth and water. If the answer is NO, then the teacher is correct in marking your dd's answer as wrong. However, we would then we need to clarify with MOE.

I have abstracted the info below on seed germination under 100% oxygen from http://www.amjbot.org/cgi/content/full/89/3/410:

\"The germination of giant foxtail seed in pure O2 was 87 ± 15% (Figs. 2 and 3). The time to germination was shorter (1 d) at all O2 concentrations greater than that of air (20%). Seed germination and time to germination did not decrease as O2 decreased from 20 to 10%.\"

[Joy]

DELETED

[atutor2001]

Joy:

May I ask, when we write Plant has a fixed cell wall, awarded full marks.

What about Plant has a rigid cell wal?Is it deduct half mark?

Thanks


Rgds
Joy

In my opinion \"rigid\" should be the correct word - not fixed. I will give zero mark for \"fixed\" as the meaning is totally different from rigid. But the wall cannot be spelled as \"wal\" - otherwise no mark as wall is the other key word.

Try googling for \"rigid cell wall\" and \"fixed cell wall\" you will find how the word \"fixed\" is used in relation to cell wall.

[Tang]

Joy:

May I ask, when we write Plant has a fixed cell wall, awarded full marks.

What about Plant has a rigid cell wal?Is it deduct half mark?

Thanks


Rgds
Joy

Hi,

Why is there a need to describe the cell wall?

I will just answer as follows:

Plants have cell walls.

or

Plants have cell walls that give them regular shape.

[Leanne]

I got a reply from her teacher:


In Science, the specific meanings of the words is important.
Different adjectives means different things in Science.
According to Longman, the word rigid means \"stiff, not moving or bending\" - a movement.
However, we are looking for the inability of the cell to change shape - because it has been fixed by the cell wall.

atutor2001:

Joy:

May I ask, when we write Plant has a fixed cell wall, awarded full marks.
What about Plant has a rigid cell wal?Is it deduct half mark?

Thanks


Rgds
Joy

In my opinion \"rigid\" should be the correct word - not fixed. I will give zero mark for \"fixed\" as the meaning is totally different from rigid. But the wall cannot be spelled as \"wal\" - otherwise no mark as wall is the other key word.

Try googling for \"rigid cell wall\" and \"fixed cell wall\" you will find how the word \"fixed\" is used in relation to cell wall.

[Leanne]

delted

]

[Full.010894Cream]

Tang:

Hi,


Why is there a need to describe the cell wall?

I will just answer as follows:

Plants have cell walls.

or

Plants have cell walls that give them regular shape.

Thinking the same thing here...is it necessary to give additional info/description? What is the context of the qn?

[Leanne]

state the function of the cell wall.

Full.Cream:

Tang:

Hi,

Why is there a need to describe the cell wall?

I will just answer as follows:

Plants have cell walls.

or

Plants have cell walls that give them regular shape.

Thinking the same thing here...is it necessary to give additional info/description? What is the context of the qn?

[Tang]

Leanne:

state the function of the cell wall.

Full.Cream:

[quote=\"Tang\"] Hi,

Why is there a need to describe the cell wall?

I will just answer as follows:

Plants have cell walls.

or

Plants have cell walls that give them regular shape.

Thinking the same thing here...is it necessary to give additional info/description? What is the context of the qn?

[/quote]
Hi,

The cell wall gives the plant a regular shape.

or

The cell wall gives the plant a good shape.

[Full.010894Cream]

think my boy was taught not to use ‘regular’ in description as it is too subjective.