Difference between Mixture and Solution
http://www.princeton.edu/~pccm/outreach/scsp/mixturesandsolutions/background.htm
Notes for Physical Science
https://www.itschool.gov.in/pdf/std_IX/eng_medium/Physical_Science/Part_I/Unit_01.pdf
https://www.itschool.gov.in/pdf/std_IX/eng_medium/Physical_Science/Part_I/Unit_02.pdf
https://www.itschool.gov.in/pdf/std_IX/eng_medium/Physical_Science/Part_I/Unit_03.pdf
Wednesday, September 28, 2011
Sunday, October 25, 2009
Common Science Questions
Respiratory Systems
Q1) After playing basketball with his friends, Tom checked his breathing rate again. He found that his breathing rate was 20 breaths per minute. Why was his breathing rate higher?
The body needs more oxygen and hence, the breathing increases.
Q2) Jerry ran around the track for 20 minutes.(a) What would happen to his heartbeat after 20 minutes? (b)Why is this so?
a) His heartbeat rate increases.
b) His heartbeat increases so that the blood will be able to transport the required oxygen and food to the different parts of the body.
Q1) After playing basketball with his friends, Tom checked his breathing rate again. He found that his breathing rate was 20 breaths per minute. Why was his breathing rate higher?
The body needs more oxygen and hence, the breathing increases.
Q2) Jerry ran around the track for 20 minutes.(a) What would happen to his heartbeat after 20 minutes? (b)Why is this so?
a) His heartbeat rate increases.
b) His heartbeat increases so that the blood will be able to transport the required oxygen and food to the different parts of the body.
Science Concept and Key Words
To ensure that you can get full mark for your science questions, first determine the concept the question is asking and answers it with the required key words.
Eg (abstracted from Road to PSLE: science blog)
A supplier transports ice blocks from a factory to a market. The ice cubes are covered with thick cloth. What is the main reason for covering the ice blocks with thick cloth? Explain
Main reason -
To prevent the ice blocks from gaining heat. [1/2 the full mark]
Explain - The thick cloth is a poor conductor of heat. [1/2 the full mark]
Ans: The thick cloth is a poor conductor of heat. It prevents the ice blocks from gaining heat (from the atmosphere and melting too quickly).( ) optional
Key concepts:
Heat flows from hotter object to cooler object (until both reach the same temperature)
Heat gains causes object to change from solid to liquid (and liquid to gas)Poor conductor of heat – Heat passes less quickly.
Key words:
Heat gain
Poor conductor of heat
Based on key concepts – may want to include Melting (as part of key words)
Link concepts with processes learnt
•Lime water -------> think of carbon dioxide ---> Respiration? Decomposition?
•Iodine -------> think of starch ---> Photosynthesis
•Water droplets -------> Condensation? Transpiration? Decomposition?
•Plant with sunlight -------> Photosynthesis?
Eg (abstracted from Road to PSLE: science blog)
A supplier transports ice blocks from a factory to a market. The ice cubes are covered with thick cloth. What is the main reason for covering the ice blocks with thick cloth? Explain
Main reason -
To prevent the ice blocks from gaining heat. [1/2 the full mark]
Explain - The thick cloth is a poor conductor of heat. [1/2 the full mark]
Ans: The thick cloth is a poor conductor of heat. It prevents the ice blocks from gaining heat (from the atmosphere and melting too quickly).( ) optional
Key concepts:
Heat flows from hotter object to cooler object (until both reach the same temperature)
Heat gains causes object to change from solid to liquid (and liquid to gas)Poor conductor of heat – Heat passes less quickly.
Key words:
Heat gain
Poor conductor of heat
Based on key concepts – may want to include Melting (as part of key words)
Link concepts with processes learnt
•Lime water -------> think of carbon dioxide ---> Respiration? Decomposition?
•Iodine -------> think of starch ---> Photosynthesis
•Water droplets -------> Condensation? Transpiration? Decomposition?
•Plant with sunlight -------> Photosynthesis?
Monday, October 19, 2009
Science Questions
Do all plants have leaves?
The simplest types of plants, like algae, don't have leaves. But they do have chlorophyll in their cells and make their own food through photosynthesis, using sunlight, water, and minerals.
Mosses have leaf-like structures that carry out photosynthesis, but they are not true leaves because they don't have the special tissues-xylem and phloem-that distribute food, water, and minerals throughout most plants. The lack of a transportation system is the reason that mosses are so tiny and low to the ground.
More complex types of plants have leaves. Leaf shape is often determined by conditions in the environment. Usually, where sunlight and water are plentiful, leaves are flat and broad, providing a large surface area where photosynthesis can take place. Where weather is cold and dry, however, water loss can be a problem. The long, needle-shaped leaves of conifer trees (including pines), for example, help retain water, allowing the plants to grow in very dry, cold places, far north or high in the mountains. The extreme environment of the desert-intensely hot and dry-has brought about other special leaf adaptations. Many desert plants have fleshy leaves (and stems) in which they are able to store large amounts of water. Over millions of years the leaves of desert cactus plants became so small-to restrict water loss through transpiration-that on many only sharp spines remain. The thick-skinned stems or branches of cactus plants now do the job that leaves do for other plants, making food through photosynthesis.
Do all plants have roots?
The simplest types of plants don't have roots. Single-celled green algae, for instance, float on water surfaces, as do many types of seaweed, which are larger types of algae. Those seaweeds that do cling to the seabed do so through growths called "steadfasts," which are not true roots. Seaweed absorbs water and minerals from the sea through all its parts.
Similarly, simple plants like mosses form low-growing mats in damp places, soaking up the moisture they need directly from their environment. Instead of roots they have thread-like growths called rhizoids that anchor them to rocks or trees.
More complex forms of plants, though, like ferns, conifers (cone-bearing plants), and flowering plants, all have true roots and stems-an internal transportation system that can move water and minerals from their source to wherever they are needed.
Land plants have two types of roots: tap roots and fibrous roots. A plant's root type is often determined by its water source. A tap root is a large, single root that grows straight down to reach water deep in the soil (with smaller roots branching off of it). Fibrous roots have no main root but spread out in a wide web to gather water located in the top layers of soil. In places like rain forests-where there is abundant plant growth with little ground space for roots and plenty of moisture-some plants grow high up in trees. These epiphytes, or air plants, have fibrous, spongy, aerial roots that get moisture from the frequent rains and take minerals from the surface of the tree on which they grow (or from the plant debris that gathers around their roots). Many orchids are epiphytic plants.
(taken from http://www.answers.com/)
How plants prepare for winter?
http://www.sciencemadesimple.com/leaves.html
What organisms are Asexual?
http://qldscienceteachers.tripod.com/biology/08reproduction/01asexual_and_sexual_reproduction.pdf
How to keep bread from getting moldy?
http://www.ehow.com/how_4851950_keep-sandwich-bread-growing-mold.html#
Internal or External Fertilisation
Fish, Amphibians & Mollusks - External
[Except for guppy,shark, molly and swordtail are internal.
Primitive salamanders have external fertilization, but most have internal fertilization. All caecilians have internal fertilization]
- disadvantage - A strong wind or current may interfere with fertilization
Mammals, Birds & Reptiles - Internal
The simplest types of plants, like algae, don't have leaves. But they do have chlorophyll in their cells and make their own food through photosynthesis, using sunlight, water, and minerals.
Mosses have leaf-like structures that carry out photosynthesis, but they are not true leaves because they don't have the special tissues-xylem and phloem-that distribute food, water, and minerals throughout most plants. The lack of a transportation system is the reason that mosses are so tiny and low to the ground.
More complex types of plants have leaves. Leaf shape is often determined by conditions in the environment. Usually, where sunlight and water are plentiful, leaves are flat and broad, providing a large surface area where photosynthesis can take place. Where weather is cold and dry, however, water loss can be a problem. The long, needle-shaped leaves of conifer trees (including pines), for example, help retain water, allowing the plants to grow in very dry, cold places, far north or high in the mountains. The extreme environment of the desert-intensely hot and dry-has brought about other special leaf adaptations. Many desert plants have fleshy leaves (and stems) in which they are able to store large amounts of water. Over millions of years the leaves of desert cactus plants became so small-to restrict water loss through transpiration-that on many only sharp spines remain. The thick-skinned stems or branches of cactus plants now do the job that leaves do for other plants, making food through photosynthesis.
Do all plants have roots?
The simplest types of plants don't have roots. Single-celled green algae, for instance, float on water surfaces, as do many types of seaweed, which are larger types of algae. Those seaweeds that do cling to the seabed do so through growths called "steadfasts," which are not true roots. Seaweed absorbs water and minerals from the sea through all its parts.
Similarly, simple plants like mosses form low-growing mats in damp places, soaking up the moisture they need directly from their environment. Instead of roots they have thread-like growths called rhizoids that anchor them to rocks or trees.
More complex forms of plants, though, like ferns, conifers (cone-bearing plants), and flowering plants, all have true roots and stems-an internal transportation system that can move water and minerals from their source to wherever they are needed.
Land plants have two types of roots: tap roots and fibrous roots. A plant's root type is often determined by its water source. A tap root is a large, single root that grows straight down to reach water deep in the soil (with smaller roots branching off of it). Fibrous roots have no main root but spread out in a wide web to gather water located in the top layers of soil. In places like rain forests-where there is abundant plant growth with little ground space for roots and plenty of moisture-some plants grow high up in trees. These epiphytes, or air plants, have fibrous, spongy, aerial roots that get moisture from the frequent rains and take minerals from the surface of the tree on which they grow (or from the plant debris that gathers around their roots). Many orchids are epiphytic plants.
(taken from http://www.answers.com/)
How plants prepare for winter?
http://www.sciencemadesimple.com/leaves.html
What organisms are Asexual?
http://qldscienceteachers.tripod.com/biology/08reproduction/01asexual_and_sexual_reproduction.pdf
How to keep bread from getting moldy?
http://www.ehow.com/how_4851950_keep-sandwich-bread-growing-mold.html#
Internal or External Fertilisation
Fish, Amphibians & Mollusks - External
[Except for guppy,shark, molly and swordtail are internal.
Primitive salamanders have external fertilization, but most have internal fertilization. All caecilians have internal fertilization]
- disadvantage - A strong wind or current may interfere with fertilization
Mammals, Birds & Reptiles - Internal
Friday, October 16, 2009
The difference between underground stems and storage roots
Stems
Some stems have been modified to perform special functions such as food storage, reproduction, protection or support. Stems for food storage, have been modified the following ways:
Rhizomes - thick horizontal stems that grow under soil. E.g. ginger, lengkuas, lotus 'root', turmeric
Tubers - swollen underground stems for food storage. E.g. potato
Corms - swollen short stem with some thin leaves for food storage. E.g. water chestnut.
However, all modified stems are true stems and have nodes (points where leaves, branches and other appendages arise) on their surface. A good example is the potato. This tuber has small scale-like leaves and tiny buds known as eyes. The eyes can sprout into new plants.
Roots
There are two main types of root systems:
Taproot system - The first root to grow is the primary root, which eventually produces many branches called secondary roots. These may branch further. The primary root continues to grow remain larger than any of the secondary roots.
Fibrous root system - The primary root also produces many secondary roots. However, the secondary roots grow in all directions and there is no prominent primary root.In some plants, the taproots become swollen or fleshy due to storage of food. Some examples are beets, carrots, Chinese radish, horseradish, radish, sweet potatoes, tapioca, turnip and yam beans. These roots are distinguished from underground stems by lacking nodes or leaf scars (left after a leaf has dropped off) and by having its growing tip protected by a root cap.
Tuesday, October 13, 2009
Interesting Parenting Article
http://simplycharlottemason.com/store/samples/Masterly-Inactivity.pdf
This article will help you to find a balance in discipline your child.
http://simplycharlottemason.com/store/samples/Education-Is.pdf
This article defines Education as an Atmosphere, a Discipline and a Life. Though it is in the context of homeschooling, the principles can be used by all parents.
http://www.listenez.net/Short%20Attention%20Span%20Tips.pdf
This article gives you ideas to help children with short attention span
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