PSLE 2012 - Science

[sammifan]

BeContented:

kiasu学生:

[quote=\"BeContented\"]DS also say different from usual. Section A - ok. Section B - tough.

Face dun look very optimistic, dun even want to say much

All he remembered was
'Adult frog live on land & tadpoles in water. State 2 advantages for it'.
:yikes:

Hi BeContented, just did ppr, the 2 advantages is that:
1: they do not have to compete for water, food and space.
2: when the frog habitate is destroyeed, the tadpole r not living in the same habitat as frog and thus will survive 2 grow into frgs, ensuring continuity of their own kind.

im p6 too!!
i put
no need to compete for food.
young will not be eaten by adult. So right??

You the GOOD !! :rahrah:
Told my son & he went 'oh yah!! Why din I think of that (2)!
So I guess it's really applying what one knows. Not something kids dun know, just can't link.
Thanks very much.[/quote]

[Ontheballmother]

Haneyi:

Ontheballmother:

One more qn - pl help. Something like that - cant recall actual qn.

What is the diff between mammals and birds?
A) bird has wings
B) there are body covering

Tks in advance.

Hello,
I put body covering as the answer.

Birds -> Feathers
Mammals -> Fur / hair

Hope this helps. ^^

Thanks! My ds too :imcool:

[Ares23]

Newton’s first law states that a body at rest will remain at rest and a boy in constant uniform motion in a straight line will remain in a constant uniform motion in a straight unless a net force acts on the body. In this case, friction is the resistive force. Thus, if the box is stationary, even if there is a push, that means there is no net force acting on the body as f=ma due to friction.

[sammifan]

hi. i put that too!! correct?? n u said "U THE GOOD’’ to the person who said compete for food?

[sammifan]

thesjarox:

vaidyanathan padmini:

How about friction question from McQ.....

My dd's answer is only C as friction opposes motion...
Only the box in c is moving so it should have friction

Confirmed with teacher-A,B and C.
Friction also acts on stationary objects. That's why forces have to overcome the friction before being able to move the object. Also, if there were no friction acting on an object,the object would glide across the surface, like ice, and would never stop.
Thus, A is also correct.

no trust me only b n c r correct.. BUT IT WAS STILL FLAT ON THE SURFACE

[sammifan]

can i ask?

which of da following conclusions r correct?
did u put more stomata found on under or upper side of the leaves?

[Fun fun]

Stomata found underside of leave

[fantasy1]

Hi


If u chked the website for friction, it is stated that friction also acts on objects that are not moving

[verykiasumummy]

sammifan:

can i ask?

which of da following conclusions r correct?
did u put more stomata found on under or upper side of the leaves?

hello sammifan,

whether there are more stomata on the upper or under side of leaves, it depends if they are land plants or aquatic plants..

land plants have upper surface facing the sun, so they have more stomata on the underside so that they would not be losing too much water.

aquatic plants (floating or partially submerged plants) have more stomata on the upper side because their underside of leaves are in contact with water, hence it makes gases exchange more efficient when more stomata are located on the upper side of the leaves..

[verykiasumummy]

btw, u should post ur question in the relevant thread instead of creating a new thread… this saves time on the admin side as they will need to move it over for u…