Q&A - PSLE Science

[Gumbokins]

Hi ps help. Many tks and God Bless:)

A marble was pushed with the same amount of force across four different types of surfaces, A, B, C and D. The table below shows the distance travelled by the marble before it came to a stop.

Surface A B C D

Distance 66 21 35 54
Travelled
(Cm)

Which one of the following sets of surfaces best matches the distances recorded above?

A B C D
(1) Aluminium Wood Glass Carpet
(2) Glass Carpet Wood Aluminum
(3) Carpet Glass Aluminum Wood
(4) Wood Aluminum Carpet Glass

Might be (2) because glass have the smoothest surface, so it will travel further and the Carpet have the roughest surface, so it will travel the least. "The smoother the surface, the further it will travel, the rougher the surface, the less further it will travel."

If there are other answers, please post. I am not very sure of the answer if I am right.

(2) is the best option, although I'm not sure a child would know which is the smoothest between wood, glass and aluminium

[Gumbokins]

Ps help. Many tks and God Bless:)

1) Mr Lim measured the initial length of the spring. Then he placed a 50g, 100g and 150g weight individually in the pan and measured the length of stretched spring and recorded the readings in the table as shown below.

Weight (g) Length of stretched spring (cm)
50 9
100 11
150 13

What is the initial length of the spring?

(1) 2cm
(2) 7cm
(3) 9cm
(4) 13cm

(2) May conducted an experiment with the flowers in the garden. She wanted to find out if a flower can develop into a fruit when a certain part of a flower is removed. She used the same type of flower for her experiment.

Flower X: Style is removed
Flower Y: Anthers are removed
Flower Z: Petals are removed

May then dusted pollen grains from the same type of flower over Flowers X, Y and Z. She observed them for two weeks. Which of the flowers are most likely to produce fruits after two weeks?

(1) Flowers X and Y
(2) Flowers Y and Z
(3) Flowers X and Z
(4) None of the flowers

1) assuming the stretch is proportional to the force, it is a 2 cm increase for every 50g so original length of spring is 7 cm

2) if the style is removed, pollination cannot take place (it is attached to the stigma). Flowers Y and Z can be pollinated -> fertilized -> fruit

[SOS mum]

Hi, ps help. Many tks and God Bless:)

Jane viewed two cells under a powerful microscope and recorded her observations in the table below.

Cell Parts Cell A Cell B

Cell wall Present Absent
ell membrane Present Present
Cytoplasm Present Present
Nucleus Present Absent
Chloroplasts Absent Absent

Which of the following are possible deductions from her observations?

(1) Cell A And Cell B are plants cells
(2) Cell A is a cheek cell but Cell B is a yeast cell
(3) Cell A is a root cell but Cell B is a red blood cell
() Cell A is a bacterial cell but Cell B is a white blood cell

Ans: 3

Option (1) and (2) can be eliminated because of cell walls
Option (4) because bacteria do not have nucleus

Thank you very much, Gumbokins

[SOS mum]

Hi ps help. Many tks and God Bless:)

A marble was pushed with the same amount of force across four different types of surfaces, A, B, C and D. The table below shows the distance travelled by the marble before it came to a stop.

Surface A B C D

Distance 66 21 35 54
Travelled
(Cm)

Which one of the following sets of surfaces best matches the distances recorded above?

A B C D
(1) Aluminium Wood Glass Carpet
(2) Glass Carpet Wood Aluminum
(3) Carpet Glass Aluminum Wood
(4) Wood Aluminum Carpet Glass

Might be (2) because glass have the smoothest surface, so it will travel further and the Carpet have the roughest surface, so it will travel the least. "The smoother the surface, the further it will travel, the rougher the surface, the less further it will travel."

If there are other answers, please post. I am not very sure of the answer if I am right.

(2) is the best option, although I'm not sure a child would know which is the smoothest between wood, glass and aluminium

Thank you very much, Gumbokins.

[SOS mum]

Ps help. Many tks and God Bless:)

1) Mr Lim measured the initial length of the spring. Then he placed a 50g, 100g and 150g weight individually in the pan and measured the length of stretched spring and recorded the readings in the table as shown below.

Weight (g) Length of stretched spring (cm)
50 9
100 11
150 13

What is the initial length of the spring?

(1) 2cm
(2) 7cm
(3) 9cm
(4) 13cm

(2) May conducted an experiment with the flowers in the garden. She wanted to find out if a flower can develop into a fruit when a certain part of a flower is removed. She used the same type of flower for her experiment.

Flower X: Style is removed
Flower Y: Anthers are removed
Flower Z: Petals are removed

May then dusted pollen grains from the same type of flower over Flowers X, Y and Z. She observed them for two weeks. Which of the flowers are most likely to produce fruits after two weeks?

(1) Flowers X and Y
(2) Flowers Y and Z
(3) Flowers X and Z
(4) None of the flowers

1) assuming the stretch is proportional to the force, it is a 2 cm increase for every 50g so original length of spring is 7 cm

2) if the style is removed, pollination cannot take place (it is attached to the stigma). Flowers Y and Z can be pollinated -> fertilized -> fruit

Thank you very much, Gumbokins.

[paperprata]

Hi all, appreciate any help for this:

Iodine question -- when iodine(to test for starch) is applied onto a leaf with green and purple colours, will the iodine react to both green and purple parts or only green part? The purple part also contains chlorophyll thus can make food and produce starch right?


Thanks!!

[Gumbokins]

Paperprata,

If the assumption is the purple parts also contain chlorophyll (it does, just more purple than green), then yes, starch will be present. Usually when testing for starch, the leaf will be decolourized.

[Crazyberry]

Pls help. Tq.

Aaron was boiling some water in a pot when he observed some white mist above the pot of boiling water. Which part of the water cycle is the white mist most similar to?

Clouds -> Rain -> water bodies -> water vapour ?

[Gumbokins]

Pls help. Tq.

Aaron was boiling some water in a pot when he observed some white mist above the pot of boiling water. Which part of the water cycle is the white mist most similar to?

Clouds -> Rain -> water bodies -> water vapour ?

mist consists of tiny water droplets (steam that condensed when it loses heat to the cooler surroundings). It is water in the liquid state, so clouds / rain / water bodies are possible. But both mist and clouds are the result of condensation. Best answer is "clouds".

[Crazyberry]

Tq Gumbokins I understand now.Appreciate it very much