Tutor Niedino: Pri Science Questions and Concepts
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Vanilla Cake:
Hi Vanilla,Hi Niedino,
Please assist to solve the following P6 Science questions:
Q1
A farmer found out that this fruit trees were infested by aphids. He wanted to use natural predator to remove the the aphids. He did a test by putting 20 predators & 100 aphids into a cage on day 1. After 5 days, he observed that the no. of predators became 15 & aphids became 98. Why did the predator decrease after 5 days?
Q2
Kelly put a leaf from a plant into a container of water. She told her friends that air bubbles would emerge from the leaf. However, when she tried, there were no bubbles coming out from the leaf. Give 2 reasons for the negative observation.
Q3
Billy carried out an experiment with 20 mealworms. The mealworms were placed in the middle of a tray. 4 types of food are placed at the corners of the tray. Billy observed that the mealworms moved towards the food. After 2 hours, he observed the following :
Fish -> 9 mealsworms
Dragonfruit -> 4 mealworms
Bread crumbs -> 2 mealworms
Tomato -> 5 mealworms
What was the aim of Billy's experiment?
Why did Billy place the mealworms in the middle of the tray at the start of the experiment?
Q4
Tim cut a leaf stalk of a water hyacinth plant in a basin of water.
a) What will he observe in the basin of water after cutting the leaf stalk of the water hyacinth?
b) Explain how the answer mentioned in part (a) helps the water hyacinth to adapt to its environment?
Q5
Peter was looking at some tadpoles in a jar.He observed that tadpoles do not look like frogs and concluded tadpoles do not inherit any characteristics from their parents.
(a)Was Peter's conclusion correct?
(b)Explain your answer in (a).
Q6
All living organisms use oxygen and give out carbon dioxide during life processes. Give a reason why there is still enough oxygen for all life on the Earth.
Thanks in advance
Sorry for the late reply. I'll try to answer the questions but the answers have to be seen in context to the questions (there might be graphs, diagrams etc ...) What's most important is to answer the questions using the concepts learnt in your child's lessons.
Q1: The aphids might not be the prey of the natural predator / the natural predator might not be able to survive on that particular fruit tree due to a change in habitat.
Q2: The leaf might have been dead for some time, hence it did not photosynthesize.
Q3: The aim of the experiment was to find out what type of food did the mealworms prefer. The reason for putting the mealworms in the middle is to ensure a fair test, so that all the mealworms start at the same point.
Q4: He would observe bubbles of air coming out of the water hyacinth stem. This helps the water hyacinth to float on water and get sunlight to make its own food.
Q5: Peter is wrong, as tadpoles go through a stage of change in which they will acquire characteristics that will resemble their parents.
Q6: There is still enough oxygen as plants produce oxygen during the process of photosynthesis, thus allowing for the renewal of oxygen in the atmosphere.
Hope these answers helps. -
starlight1968sg:
Hi, you can use the process of photosynthesis as the basic concept to help you understand this.Insecticides are sprayed onto the plant. They entered the soil and get absorbed by the plant. The insecticides are found in the xylem-water carrying tubes.
Insects eat the sugar (food) made by the leaves of the plant. This sugar is found in the phloem.
How do the insecticides kill the insects?
Thanks.
Carbon dioxide + Sunlight + Water => Sugar + Oxygen
Where does the water come from? The xylem of course. So this is how the insecticide kills the insect, after the contaminated water is used by the plant to make food, which the insect consumes and dies. -
Niedino:
For Q1, can't the predators share a predator prey relationship amongst themselves? Maybe I'm wrong, but just wondering.
Hi Vanilla,Vanilla Cake:
Hi Niedino,
Please assist to solve the following P6 Science questions:
Q1
A farmer found out that this fruit trees were infested by aphids. He wanted to use natural predator to remove the the aphids. He did a test by putting 20 predators & 100 aphids into a cage on day 1. After 5 days, he observed that the no. of predators became 15 & aphids became 98. Why did the predator decrease after 5 days?
Q2
Kelly put a leaf from a plant into a container of water. She told her friends that air bubbles would emerge from the leaf. However, when she tried, there were no bubbles coming out from the leaf. Give 2 reasons for the negative observation.
Q3
Billy carried out an experiment with 20 mealworms. The mealworms were placed in the middle of a tray. 4 types of food are placed at the corners of the tray. Billy observed that the mealworms moved towards the food. After 2 hours, he observed the following :
Fish -> 9 mealsworms
Dragonfruit -> 4 mealworms
Bread crumbs -> 2 mealworms
Tomato -> 5 mealworms
What was the aim of Billy's experiment?
Why did Billy place the mealworms in the middle of the tray at the start of the experiment?
Q4
Tim cut a leaf stalk of a water hyacinth plant in a basin of water.
a) What will he observe in the basin of water after cutting the leaf stalk of the water hyacinth?
b) Explain how the answer mentioned in part (a) helps the water hyacinth to adapt to its environment?
Q5
Peter was looking at some tadpoles in a jar.He observed that tadpoles do not look like frogs and concluded tadpoles do not inherit any characteristics from their parents.
(a)Was Peter's conclusion correct?
(b)Explain your answer in (a).
Q6
All living organisms use oxygen and give out carbon dioxide during life processes. Give a reason why there is still enough oxygen for all life on the Earth.
Thanks in advance
Sorry for the late reply. I'll try to answer the questions but the answers have to be seen in context to the questions (there might be graphs, diagrams etc ...) What's most important is to answer the questions using the concepts learnt in your child's lessons.
Q1: The aphids might not be the prey of the natural predator / the natural predator might not be able to survive on that particular fruit tree due to a change in habitat.
Q2: The leaf might have been dead for some time, hence it did not photosynthesize.
Q3: The aim of the experiment was to find out what type of food did the mealworms prefer. The reason for putting the mealworms in the middle is to ensure a fair test, so that all the mealworms start at the same point.
Q4: He would observe bubbles of air coming out of the water hyacinth stem. This helps the water hyacinth to float on water and get sunlight to make its own food.
Q5: Peter is wrong, as tadpoles go through a stage of change in which they will acquire characteristics that will resemble their parents.
Q6: There is still enough oxygen as plants produce oxygen during the process of photosynthesis, thus allowing for the renewal of oxygen in the atmosphere.
Hope these answers helps.
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MdmKS:
Hi MdmKS,
Vanilla Cake and all, any good assessment or test papers which meet the needs of above test type (3)?Vanilla Cake:
Hi atutor2001,
Thks for your helpful replies.
This year's PSLE 2010 Science will be an interesting one to watch:
(1) 20% contention reduction.
(2) OE questions reduced from 16 to 14.
(3) Process skills are made explicit:
(a) Inferring (Generating - draw inferences)
(b) Predicting (Generating - making predictions)
(c) Generating possibilities (Generating - suggest ideas)
(d) Formualting hypothesis (Generating - construct a hypothesis)
and my younger sister will be the 2nd batch of PSLE students to take this revised PSLE Science in 2011.
Pls refer to my mum's posted http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=11079&postdays=0&postorder=asc&start=10 plus doing past years Science papers from other schools. -
Hi all,i was wondering if using mindmaps for revision for science or point form better?Or there are other ways better than these two?
Between,for science questions,there'll be lines for writing answers right? Does many lines means need longer answer? What about only one line? Does it means it only need a few words as answer?
:thankyou: -
Hi Niedino,
Thks for your replies and I have some queries.Vanilla Cake:
Q1
A farmer found out that this fruit trees were infested by aphids. He wanted to use natural predator to remove the the aphids. He did a test by putting 20 predators & 100 aphids into a cage on day 1. After 5 days, he observed that the no. of predators became 15 & aphids became 98. Why did the predator decrease after 5 days?Niedino:
If the aphids are not the preys of the natural predators, why did the farmers carry out the test with the natural predators?Q1: The aphids might not be the prey of the natural predator / the natural predator might not be able to survive on that particular fruit tree due to a change in habitat.
Vanilla Cake:
Q2
Kelly put a leaf from a plant into a container of water. She told her friends that air bubbles would emerge from the leaf. However, when she tried, there were no bubbles coming out from the leaf. Give 2 reasons for the negative observation.Niedino:
The question asks for two reasons, not one.If the leaf is dead, why was it used for the experiment?Q2: The leaf might have been dead for some time, hence it did not photosynthesize.
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Niedino:
Hi Niedino,
Hi, you can use the process of photosynthesis as the basic concept to help you understand this.starlight1968sg:
Insecticides are sprayed onto the plant. They entered the soil and get absorbed by the plant. The insecticides are found in the xylem-water carrying tubes.
Insects eat the sugar (food) made by the leaves of the plant. This sugar is found in the phloem.
How do the insecticides kill the insects?
Thanks.
Carbon dioxide + Sunlight + Water => Sugar + Oxygen
Where does the water come from? The xylem of course. So this is how the insecticide kills the insect, after the contaminated water is used by the plant to make food, which the insect consumes and dies.
Pls help to clarify:
When the insect eat the leaves, how does it know it is eating the food carrying tubes only and not the water carrying tubes?The food and water carrying tubes are the transport system, how does the insect differentiate them? -
[quote]When the insect eat the leaves, how does it know it is eating the food carrying tubes only and not the water carrying tubes?The food and water carrying tubes are the transport system, how does the insect differentiate them?[/quote]
Photosynthesis is carried out on the leaves (that's where chlorophyll is). So the leaves would have water, using this formula :
Carbon dioxide + Sunlight + Water => Sugar + Oxygen.
Food carrying tubes flow downwards, I mean the nutrients.
Water carrying tubes flow upwards, I mean the water. -
Hi everyone
Am new to the forum and trying to learn as much as I can to help my ds.
I have been trying to understand into the details of this simple equation and hope someone can help to get it right.thanks
Carbon dioxide + Sunlight + Water => Sugar + Oxygen.
LHS is for photosynthesis to take place, RIGHT hand side as in sugar, can someone pls explain how starch and sugar link into this?thanks alot.
May I aslo check, for science new syllubus, is spine etc included for the psle?caroline3sg:
Photosynthesis is carried out on the leaves (that's where chlorophyll is). So the leaves would have water, using this formula :[quote]When the insect eat the leaves, how does it know it is eating the food carrying tubes only and not the water carrying tubes?The food and water carrying tubes are the transport system, how does the insect differentiate them?
Carbon dioxide + Sunlight + Water => Sugar + Oxygen.
Food carrying tubes flow downwards, I mean the nutrients.
Water carrying tubes flow upwards, I mean the water.[/quote] -
Hi MOE H, Leanne & Vanilla,
Just to clarify, the emphasis on Primary Science is on process skills, especially with the content reduction in the new syllabus. Hence, it is important to teach your children to identify the types of thinking needed. For a list of thinking processes, you may refer to the Science
syllabus.
From the questions you have posted Vanilla, I assume that your child has difficulty with inference and deductive questions. Here's the thinking that should be going on in your child's mind when attempting the question.
E.g. Why did the predators decrease more than the aphids? Perhaps they are not the predators of aphids. Perhaps the habitat is not suitable for them. (MOE H, they might be eating each other so it's not impossible)
E.g Why did the leaf not have bubbles? Perhaps the stomata is blocked? The leaf might have been plucked sometime ago and cannot photosynthesize.
E.g what makes the insecticide work? The water is contaminated so how does that get into the food?
Inferring is basically a series of intelligent
guesses based on the knowledge given in the question.
Leanne, the equation is very simple and there are no molecular quantities, it's just to prepare the pupils
Hope this helps
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