Tutor Niedino: Pri Science Questions and Concepts
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I was going through the topic of heat with my pupils when I realised that many pupils had the misconception that only certain things have heat, and \"cold\" things like ice cubes do not have heat. Here goes ... All things have heat energy, even dry ice and ice cubes. For an ice-cube the amount of heat energy, or degree of hotness can be measured by their temperature, which is 0 degrees celsius. Many pupils misunderstand this and think that cold objects have no heat energy, which is wrong.
So try it with your child and ask whether there's heat energy in an ice-cube. You can then develop this concept with them.
Hope it helps! -
Niedino:
If you say same substance ie blood, then I agreed. But the \"argument\" here is \"substances\" mentioned in the option B.
Hi,starlight1968sg:
Hi,
I need some help in
http://www.orlesson.org/orp/09Sc/2009-Sc-CA2-Nanyang.pdf Q24
Is the model ans correct in particular option B?
MTIA.
The answer should be (3). Option B is correct, as I assume the same substance mentioned here is blood.
OT here:
Thanks for pointing out about heat in all objects.
Another thing to clarify:
(1) blood in the artery (ie leaving the heart) is richer in oxygen but does not mean it has no carbon dioxide.
(2) the air we breathe out contains water vapour and more carbon dioxide but does not mean it has no oxygen.
Am I correct?
MTIA. -
starlight1968sg:
If you say same substance ie blood, then I agreed. But the \"argument\" here is \"substances\" mentioned in the option B.
Hi,Niedino:
[quote=\"starlight1968sg\"]Hi,
I need some help in
http://www.orlesson.org/orp/09Sc/2009-Sc-CA2-Nanyang.pdf Q24
Is the model ans correct in particular option B?
MTIA.
The answer should be (3). Option B is correct, as I assume the same substance mentioned here is blood.
OT here:
Thanks for pointing out about heat in all objects.
Another thing to clarify:
(1) blood in the artery (ie leaving the heart) is richer in oxygen but does not mean it has no carbon dioxide.
(2) the air we breathe out contains water vapour and more carbon dioxide but does not mean it has no oxygen.
Am I correct?
MTIA.[/quote]
Both are absolutely correct but there is something that I want to point out here.....
Arteries are NOT defined by the fact that they carry blood rich in oxygen and veins are NOT classified by the fact they contain large amounts of carbon dioxide.
They are actually classified based on the thickness of their walls. Arteries have thick walls while veins have thin walls. The reason behind is that arteries are blood vessels transporting blood leaving the heart while veins carry blood back to the heart. When the heart pumps, it pumps with great force so the artery walls have to be thick so that they do not burst under the high pressure of the blood flowing. Conversely, blood travelling in the veins have lost most of their momentum thus the vein walls do not have to be thick.
Generally, yes, arteries carry oxygen rich blood while veins transport carbon dioxide rich blood. However, there are 2 exceptions, one in each case. Blood pumped from the heart to the lungs is rich in carbon dioxide but still travels in an artery as it is leaving the heart. On the other hand, blood leaving the lungs to the heart is rich in oxygen but travels in a vein as it is returning to the heart.
Although it is not in the syllabus, I believe it is essential for us to take note of this. I have seen questions when they ask why is the artery wall thick. Of course, the chid's prior knowledge on forces would be sufficient to answer the question but some children, despite getting the right answer, may have second thoughts. Blood leaving the heart to the lungs is rich in carbon dioxide. According to their answer, it should be an artery but then again they think its carbon dioxide rich, a vein. As a result, some children change their answer to another ridiculous one and lose their marks. Having such external knowledge certainly give them an edge over others and they do not start panicking when they see a confusing question.
Hope I have not bored you to death. Please reply if this explanation is confusing. Sometimes my language gets in over my head and makes it difficult to comprehend the scientific concept behind.
-
MOE Hater:
Thanks so much for sharing esp on why arteries have thicker walls!Both are absolutely correct but there is something that I want to point out here.....
Arteries are NOT defined by the fact that they carry blood rich in oxygen and veins are NOT classified by the fact they contain large amounts of carbon dioxide.
They are actually classified based on the thickness of their walls. Arteries have thick walls while veins have thin walls. The reason behind is that arteries are blood vessels transporting blood leaving the heart while veins carry blood back to the heart. When the heart pumps, it pumps with great force so the artery walls have to be thick so that they do not burst under the high pressure of the blood flowing. Conversely, blood travelling in the veins have lost most of their momentum thus the vein walls do not have to be thick.
Generally, yes, arteries carry oxygen rich blood while veins transport carbon dioxide rich blood. However, there are 2 exceptions, one in each case. Blood pumped from the heart to the lungs is rich in carbon dioxide but still travels in an artery as it is leaving the heart. On the other hand, blood leaving the lungs to the heart is rich in oxygen but travels in a vein as it is returning to the heart.
Although it is not in the syllabus, I believe it is essential for us to take note of this. I have seen questions when they ask why is the artery wall thick. Of course, the chid's prior knowledge on forces would be sufficient to answer the question but some children, despite getting the right answer, may have second thoughts. Blood leaving the heart to the lungs is rich in carbon dioxide. According to their answer, it should be an artery but then again they think its carbon dioxide rich, a vein. As a result, some children change their answer to another ridiculous one and lose their marks. Having such external knowledge certainly give them an edge over others and they do not start panicking when they see a confusing question.
Hope I have not bored you to death. Please reply if this explanation is confusing. Sometimes my language gets in over my head and makes it difficult to comprehend the scientific concept behind.
Yes, I know about the pulmonary artery and pulmonary vein.
To make it more precise, arteries carrying blood from the heart to the rest of the body is richer in oxygen except pulmonary artery.
Back to the thickness of artery, vein and capillaries, why capillaries have the thinner walls than veins?
MTIA. -
starlight1968sg:
Wow, I've learnt alot as well. Thanks MOE Hater, and Starlight. In the primary syllabus, we teach that capillaries have the thinnest walls as they allow substances such as oxygen, digested food to pass through to other parts of the body. This is a simple explanation, as we have to understand that our pupils are only 11 years old when they learn this topic.
Thanks so much for sharing esp on why arteries have thicker walls!MOE Hater:
Both are absolutely correct but there is something that I want to point out here.....
Arteries are NOT defined by the fact that they carry blood rich in oxygen and veins are NOT classified by the fact they contain large amounts of carbon dioxide.
They are actually classified based on the thickness of their walls. Arteries have thick walls while veins have thin walls. The reason behind is that arteries are blood vessels transporting blood leaving the heart while veins carry blood back to the heart. When the heart pumps, it pumps with great force so the artery walls have to be thick so that they do not burst under the high pressure of the blood flowing. Conversely, blood travelling in the veins have lost most of their momentum thus the vein walls do not have to be thick.
Generally, yes, arteries carry oxygen rich blood while veins transport carbon dioxide rich blood. However, there are 2 exceptions, one in each case. Blood pumped from the heart to the lungs is rich in carbon dioxide but still travels in an artery as it is leaving the heart. On the other hand, blood leaving the lungs to the heart is rich in oxygen but travels in a vein as it is returning to the heart.
Although it is not in the syllabus, I believe it is essential for us to take note of this. I have seen questions when they ask why is the artery wall thick. Of course, the chid's prior knowledge on forces would be sufficient to answer the question but some children, despite getting the right answer, may have second thoughts. Blood leaving the heart to the lungs is rich in carbon dioxide. According to their answer, it should be an artery but then again they think its carbon dioxide rich, a vein. As a result, some children change their answer to another ridiculous one and lose their marks. Having such external knowledge certainly give them an edge over others and they do not start panicking when they see a confusing question.
Hope I have not bored you to death. Please reply if this explanation is confusing. Sometimes my language gets in over my head and makes it difficult to comprehend the scientific concept behind.
Yes, I know about the pulmonary artery and pulmonary vein.
To make it more precise, arteries carrying blood from the heart to the rest of the body is richer in oxygen except pulmonary artery.
Back to the thickness of artery, vein and capillaries, why capillaries have the thinner walls than veins?
MTIA. -
starlight1968sg:
the exchange of gases between the artery and the surrounding body tissues take place thru capillaries. The thin wall of the capillaries (cappilaries are just a single cell thick, i think) facilitates this.
Thanks so much for sharing esp on why arteries have thicker walls!
Yes, I know about the pulmonary artery and pulmonary vein.
To make it more precise, arteries carrying blood from the heart to the rest of the body is richer in oxygen except pulmonary artery.
Back to the thickness of artery, vein and capillaries, why capillaries have the thinner walls than veins?
MTIA. -
Sorry, I am kay pohing
Sun_2010:
the exchange of gases, nutrient/food; waste; water ... between the blood vessels and the surrounding body tissues take place thru capillaries. The thin wall of the capillaries (cappilaries are just a single cell thick, i think) facilitates this. -
Is water hyacinth a floating or partially-submerged plant? Different Science guidebook categorise them differently.
What about Cattail? It was indicated as partially-submerged plant in one of the guidebooks but my child says his tutor told him it should be totally-submerged.
Thanks -
leesf:
Cattail shd be partially submerged since the 'cattail' is above water.Is water hyacinth a floating or partially-submerged plant? Different Science guidebook categorise them differently.
What about Cattail? It was indicated as partially-submerged plant in one of the guidebooks but my child says his tutor told him it should be totally-submerged.
Thanks
As for water hyacinth, it shd be floating since it roots is not anchored to the bed of the pond/pool.
Juz my 2c -
Hi all,
Its been some time since I last posted. Here are some misconceptions on the digestive system that your child might have.
Gullet: This is an organ that contains quite a few misconceptions.
1. Is it an organ? Yes it is. Many pupils often think that it is just a tube, but it is an organ. It is a muscular tube that pushes food down.
2. There is no digestion in the gullet. True and False. The gullet does not produce digestive juices, so it does not digest food. But the food that goes down the gullet is mixed with saliva and hence, a little digestion does take place in the gullet.
3. The gullet and the windpipe are one and the same. False. The gullet and the windpipe are often seen in rudimentary diagrams as being in the same position, hence the misunderstanding. They are actually different tubes, and there is a flap that prevents food from entering the windpipe during swallowing.
Hope it helps. I'm thinking of setting up a blog for Science misconceptions and sharing as it does take a bit of time for me to do it on a forum. If I do, I'll post up a link here.
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