Pei Hwa Presbyterian Primary
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IJJ:
I ever read from a text before that air does enter into water w/o pump. But, the solubility of O2 is low in water. For an aquarium, I think pump is used to filter, and pump in more oxygen to supply the fishes. :lol:
Yes, the concentration of dissolved oxygen in the water will vary so there is a need of an air pump or an aerator to maintain the oxygen level in the water. I am no fish rearing expert though. This is what I read and understood. -
E3:
The fish that my dds brought home from the Pasir Ris Farm can survive without an airpump for weeks. I think they died one by one due to neglect.
How oxygen is dissolved requires in-depth scientific explanation which might need the expertise of a Scientist. However, oxygen in the water comes largely from the atmosphere. Faster moving water absorbed more oxygen compared to still water.Jennifer:
Wld someone pls enlighten me how can air enters into the stagnant water in setup A?
[quote]I was told I needed an air pump for our fish tank, else the oxygen in the water is not replenish and the fishes will die. Was I tricked by the shopowner?
[quote]I am always under the impression that fish will swim near the water surface to gasp for air when there is insufficient oxygen in the water (again told by someone).[/quote]Fish do not \"gasp\" for air unless their gills are damaged. They only take in dissolved oxygen in the water.
[quote]but knowing how fishes in water take in oxygen via their mouth n passing the water through their gills, how do the fishes then breathe near water surface?[/quote]My assumption, they swam near the water surface because the movement they created at the surface will cause more oxygen to be dissolved into the water so they can take in the dissolved oxygen near the surface.[/quote]Hm, very much enlightened now. :thankyou: -
IJJ:
Personally, for this particularly question, I do not think that the comparison word is the key here. I felt the scientific knowledge of the lack of dissolved oxygen due to the oil blockage on the water surface that led the guppy's unfortunate ending is what was being tested on.I think when they ask such question, they are looking for comparison..'lesser', 'hotter', 'shorter' are comparison. Or lor lor so so like mine to state how one differs from the other. I hope I am right.
Usually, the comparison questions are from interpretation of graphs or deduction from a table. Pertaining to this guppy question, we can create a graph showing the decremental effect of the dissolved oxygen level in the water over time for Setup B, thus if a question is asked about the graph, we can answer in such a way:
The longer the time, the lesser is the level of dissolved oxygen in the water. OR
The level of dissolved oxygen decreased over time.
Both acceptable.
Actually, this question might lead to another question on water pollution...but that's another story lah.
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Happy Mama:
I am swamped :imdrowning: at what has 'transpired' between you gals/guys here..... :salute: :salute:
Hahaha! I was just pulling their legs la. There's no way I can have the skin of a 16-year old at this age!! :lol: :lol: :lol:
No wonder so many GMs / KGMs, and so many mouths to 'dou-jui here, dou-jui there'.....
Btw.......so I can see few pple here also growing taller suddenly .....no wonder I can see you better laa.... :laugh: :laugh: -
Funx3:
Go Go all the way :ugogirl:
But I want her to Continue Her Normal CCA,
(She still Attend Gym Training on Thu, Fri, Sat and Calligraphy and Chinese Dance Class on Sun prior to CA1 Week)
Want to See How Much She \"RETAINS\" from her T's Class in School ....
Then Got More things to Feedback to T on Fri -ma!
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IJJ:
So lor-suo pays off during exams :rahrah:
\"On the other hand, set up A allows oxygen entering into the water continuously. As a result, guppy in set up B is likely to die before guppy in setup A.\"
Lor-so. -
from an article:
When school officials from across the world come here to learn why Singapore’s students score so well on international science and math tests, it doesn’t take them long to discover the secret – a national obsession with education.
It even shows up on its dollar bills. While US and Latin American currencies portray images of national independence heroes, Singapore’s 2-dollar bill – the most widely circulated since there is no smaller denomination – shows students in a classroom listening to a professor, with a university in the background. Underneath, there is just one word, “Education.”......
---after i read this, then i check $2 bill carefully to see ...really have a word \"education\" . -
Hi, my child who is currently in pri 5 is getting bands 2 and 3s for his subjects he even failed his higher chinese is this bad?
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angtzeming:
Hi, my child who is currently in pri 5 is getting bands 2 and 3s for his subjects he even failed his higher chinese is this bad?
Hi Hi, welcome! Yup, its common. But I tink their results will pick up in SA1. -
he has
50+for math
70+for science
60+for english
60+for chinese
40+for higher chinese…
is this really bad?
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