How To Soar in PSLE - BTPS Way!!
Interact with complex questions / graphs / pictures to pick up valuable clues (don't highlight - just use your pen to underline words or scribble notes)
Start with Booklet A and do it meticulously with full focus - explore all 4 distractors before making final choice.
MANAGE your TIME - to score well, you need to try to finish ALL questions.
Specific answers = answers that are relevant to question.
When confused, choose any of the following strategies:
1. Ask, "What Science idea is being used in question?"
2. Pose other questions to clarify your thoughts
3. COMPARE to another set-up
4. COMPARE to a reverse situation
5. Connect to your knowledge in life (yes, you do have lots of prior / other knowledge)
6. Break down your answer in steps before crafting final answer.
Common problems with wrong answers:
*Answers are generic/vague and do not connect to that specific question
*Answers are not scientific and do not explain using Science ideas
*Answers do not make use of data provided when asked
*Answers did not make comparisons - use words like more/most etc..when asked
BTPS supports all P6 in achieving their PSLE GOALS!!
POST-IT notes - Science Magic
What enables Post It notes to stay up on any surface?
Explain how that helps to keep the note up.
(When in doubt, ask other questions that can help you clarify how to answer the question)
Science Around Me (SAM)
SAM is a Science journal that allows pupils to express themselves in their favourite ways about Science.
SAM is another great opportunity for pupils to THINK and TALK Science in a medium that is customised to their learning styles.
SAM allows teachers to informally assess understanding of the child and clarify misconceptions in their learning.
When Ice Changes into Water by Goh Chee Yan - 5G
Do you wonder whether the mass of ice changes when it melts into water. Try this out:
1. Put a few ice cubes into a plastic bag
2. Tie the mouth of the bag tightly
3. Weigh the bag of ice cubes (if there is condensation outside the bag, wipe it dry before weighing)
4. Place the bag in the sun
5. When ice has melted, wipe the outside of the bag dry (refer to step 3)
6. Weigh the bag
You will discover that the mass of the bag remains the same!
There is no change in mass when ice melts!!
22 comments:
I think its sticky surface helps it to stay up in any surface. I think it is the same principle as the velcro we have on our shoes. It secures and stays there.
Ong Yan Quan 6F
there is this sticky thing at the back of it...its like glue...but the sticky surface would eventually wear off
nadiah
6faith
I think it is the sticky surface that helps it . But i think it can stay there of a bit of help from friction too ,because think that the sticky thing cannot withstand too much of the gravitational force , and friction will be there to help.
liping~6G
i think that the sticky surface helps it to stick to any surface.But friction can also help it to stay there as Post-it notes cannot withstand so much gravitonal force.But the sticky surface would still wear off.
Jerome 6F
Post it notes has some sort of glue that will keep the note on a surface. I also realise that the glue is not really durable because it depends on the surface it is being place on and the condition. Uneven surfaces might cause it to fall as lesser surface of the post it note (the part with glue) touches the surface, hence causing lesser friction between the note and the wall as friction plays a part. I believe friction plays the main role of this question because by putting glue meaning increasing friction between the wall and the note so that it will overcome the gravity acting on it. To answer the question - Why will the glue wear off? I think that dust is everywhere, when you stick the post it note on the surface of something, the part with glue will collect dust, thus covering parts of the glue, enabling it to wear off. I think post it note also have a very special glue because when you stick it on a paper, a week later, when you take it off, it will not tear or do any harm to your paper, whereas scotch tape will. Thus, post it note is good for reminders but not good at writting important notes.
+ZoEn+ ~6 G~
In order for me to explain this question, I need to take you on a little history tour... In 1968, Dr. Spencer Silver, a scientist at 3M in the United States, with the help of Jesse Kops, a fellow scientist, accidentally developed a "low-tack", reusable pressure sensitive adhesive. For five years, Silver promoted his invention within 3M, both informally and through seminars, but without much success. In 1974, a colleague of his, Art Fry, who had attended one of Silver's seminars, came up with the idea of using the adhesive to anchor his bookmark in his hymnbook. This development of a reusable and not strong glue actually allow us to stick it. It is not use everywhere though, certain rough surface or very smooth surfaces wont allow it to be stuck. (By the way, it is almost impossible for you to remove the glue from the paper!)
Sources: Wikipedia, the free encyclopedia
Questions: Notes stay up surface, what science concept? Difference between using glue? Why no leave marks or residue?
The notes will stay up because of its unique feature, a re-adherable strip of adhesive on the back. Damn, this question is very hard! Thinking!YES!! Normal glue or white glue have a mixture of ingredients (typically polymers) dissolved in a solvent.So when the solvent evaporates when you glue it on, the glue hardens. Thus normal glue will leave a mark when you take it off as the glue is already harden. The stick glue is something like contact adhesive. They need to be pushed together, thus when they are pushed together, the bond forms very quickly.
The Post it notes are pressure-senstive adhesive, they are very similar to blu-tack which works in almost the ssame way. Both have a low vapour pressure thus gravity has lesser chance to wear it off.
Friction is important too, thus Post it notes have a long surface area so friction can overcome gravity. They placed the glue all over the surface area and the glue is actually very thin as it is being burnt and heated before placing them in. But when a strong wind blow, the notes may wear off.Surface factors such as smoothness, surface energy, removal of contaminants, etc. are also important to proper bonding.
They are also now being computerised. So much for 1 Q, I am going to die what about the rest???
Marcus Chioh
The main reason that Post-it notes can stay up on any surface is probably due to the sticky surface located at the back of the note. It is another form of glue, but not the normal type, as they can be removed for a few times whereas the normal glue cannot do that. However, the glue is not durable after a while and I noticed that sometimes it will turn a bit black. It might be a kind of glue that looks like a gel though.
The frictional force between the Post-it notes and the wall may have helped the notes as they cannot overcome the gravitational force when it is placed at a very high place. But I guess the frictional force is sometimes not strong enough to keep the Post-it notes up when there is a big wind blowing towards its direction. It will wear off a few weeks later, so it is best to just write reminders on them. We might save paper if we keep using Post-it notes (have no idea whether that is true but that is my opinion).
Si Jia
6 Grace
I think that the post it surfaces have glue stuck to them but it wears off soon after we use it for some time. For improvements:we can attach some kind of tag onto the sticky portion so that it can retain its stickiness for some time and then remove it if we want to use it.
S.L.Keerthanna 6charity
There's a small layer of glue that is on the back of the Post-It note. This helps it to stay on the surface.
When the glue come into contact with the surface, there will be friction, preventing it to fall off. Besides that, the layer of glue also help secure it enough so that the gravitational force will not overcome the glue and cause the post-it note to fall off the surface.
sorry! the comment above is mine...
Chen Zung
6 Grace
The sticky surface of the other end of the Post It note enables the note to remain on the surface. There is also friction between the wall and the note which helps prevent the note from succumbing to the gravitational force of the Earth.
However, the sticky side would not last long as the wall,no matter how clean it is, would always have some dust particles on it. Thus, the dust particles on the wall would stick onto the surface of the sticky side and cover it. Over a long period of time, the sicky side would lose its "stickiness" and fall down from the wall.
~Nicholas King(6C)
There is a layer of glue on a part of the post it note. The glue is not the same as the normal glue we use everyday. Because we can paste and peel off the post it note, thus the glue used is different. As compared to the normal glue, once pasted, sometimes, it can hardly be peeled off. Even so, it would leave behind a mark.
We know friction can be both harmful and useful to us humans. Here, friction is used as a useful thing. When the glue is pasted onto a surface, there is more friction between the surface and the note. If we compare it when there is no glue, the paper will only stay there for a while, and soon be blown away because there is not much friction between the note and the surface. The sticky part is actually a little bit uneven, unlike the part without glue, so the amount of friction will increase, thus sticking.
Sometimes we see that after a while, the note does not stick as well anymore. But why? It is actually because after using it for a lot of times and being stuck onto many different surfaces, it has collected dust. The dust has 'covered' up the sticky part, so that is why we will see some parts black or grey.
Wu Xinyi 6Grace
It is the sticky area at the back of the post it note and that sticky are is like a layer of glue but the sticky area would eventually wear off. I think there is a sticky area because the note cannot withstand too much gravity so the sticky area is there to create friction.
Rachel Ngo[6G]
uhhh...glue? Maybe the glue increases friction between the surface and the note so much that even gravitational force cant pull it down? Timothy 6G
It is the sticky surface at the back of the Post-It-Notes that helps to remain on the wall or any other surface. The Post-It-Note may not be able to stick on surfaces that are smooth or wet, like water.Thus, I think that the Post-It-Note can stick on the wall because of friction. Other than friction, the sticky surface is like glue, so, anything that lies on the sticky surface, will not be able to remove unless we remove the sticky surface too. On the wall, there is dust particles everywhere, so, as time pass by, dust collect and will soon drop off the surface. On very smooth surfaces, but not wet, like glass, it can still stick onto it. I would rather think that the Post-It-Note is somehow like the Blu.Tack. When we apply force on the other side of the sticky surface to make it stick on glass, this is where friction comes in. The sticky surface not only acts as a glue, I think that it somehow increases friction between the sticky surface and the glass, enabling it to stick on the smooth surface of the glass for a longer time. Also, if placed on an uneven surface, it will drop off quicker than compared to when placed on an flat surface, as, when stuck onto and uneven surface, the surface area of the sticky surface is lesser than when stuck onto a flat surface. So, the Post-It-Note depends on the sticky surface that acts like a glue and increases friction between the surface and itself.
6Grace-Yilin
i dont agree with yan quan. the velcro we have on our shoes is not sticky . further more , the 'hairs' on both side of the velcro . the sticky surface ,from the post it notes,when taken away after stuck on the wall, and done for a few times,it is not as sticky as before. so it is not REALLY secure and stays there.the post it notes, i agree is able to stick on the wall by its sticky surface, acting like a glue.
Ong Yan Ting 6g
The typ of glue used is strong but not too strong and it also helps to increase the friction but not too much, thus the post-it note can be used again and again.
-benjamin
-6 grace
Normal glue is hard while post it glue is soft and weak.So if the glue is hard,it is lack of flexiblity and therefore it cannot be pulled of easily so even if it is pulled out it will leave a mark on the surfce.It won't leave a mark only when pulled out of the surface when the glue has not harden which also means the glue is still flexible and can be pulled out. likewise the glue used for the post it note has not harden/dried so it is flexible and is able to be tore of easily without leaving a mark, but if the glue is not harden, how can it not get stuck on to our hands? I think because the glue used is very weak unlike the normal glue and it does not dry off easily.
Friction between the surface and the post it is also very important it heips the hold the note up while the glue helps it to stick on and tear off.The friction have to overcome the gravitational potential energy that also means the paper have to be very light and the glue have to be able to increase the friction between the surface and the post it.so may be the glue on the post it note have small particles that are not as sticky as the normal glue's particle so it increases friction and is not as sticky as the normal glue
Ruyan 6grace
In 1986 Dr. Spencer Silver came up with a unusual adhesive.It formed itself into tiny spheres with a diameter of a paper fiber.These spheres would not dissolve and could not be melted and each of them were very sticky.It is because they had made intermittent contact,they did not stick strongly when coated on tape backings.At that time this invention was thought to be very interesting but useless.
In 1974 Art Fry applied the possibilities of this adhesive that would't stay stuck to the problem he was having with his hymnbook.He have a odd habit of fluttering out between services Minnesota (a member of St.Paul)scrambling for his place during his second services.A inspiration struck this frustrated Minnesota.Could the 'unglue' be the answer?When a strip of paper was paste on the object and will be able to stay in place yet it can still be removed easily without harming the pages?Fry's temporarily bookmarks proved ananswer to his prayers.The bookmarks funtion as well as what Minnesota hoped.However these glue does not stick well on rough surfaces.I believe that friction also help to contribute to help it remain stuck to the object as glue increases friction between the surface of the object.
juanpang
I read that the inventor for the post-it notes accidentally created a weak glue that was too weak to hold things together but realised that when applied to one side of a paper it was able to stick on a hard surface that was not too smooth nor rough.However,when used for too long,the glue eventually loses its stickiness and come off.
Did you know that post-it notes in the past were all yellow but now they have taken on many different colours.
Amazingly this invention with such a flaw has taken off in the world.
Celine 6C
I think the sticky surface,which I think is like double sided tape,helps it to stay up.
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