Today we went through the topics for Primary 3, namely, Animal, Fungi, Bacteria and Materials.
Quick recap:
Living Things
1.Livings can grow, respond to changes, die, reproduce, need air, food and water to survive.
2.Plants can make their own food but animals depend on others for food.
3.Plants and animals can move by themselves but animals can move from place to place by themselves while plants can only move their parts.
4.Some animals lay many eggs at one time to ensure the survival of their species.
5.Microorganisms are living things that can only be seen under the microscope.
6.The animal groups are mammals, fish, amphibians, reptiles, birds and fish. (For characteristics, please look at Textbook Pg 46)
Mammals- outer covering of hair or fur
- Give birth to young alive (exceptions are platypus and spiny anteater which lay eggs)
- Feed on mother's milk
- Dolphins and whales are mammals. Bats are also mammals.
Reptiles- Dry skin covered with scales or shells
- Breathe through lungs
- Lay eggs
- Crocodiles, snakes and turtles are reptiles
Insects - hard outer body covering (exoskeleton)
- body divided into 3 parts (head, thorax and abdomen)
- A pair of feelers are at the head, 6 legs are at the thorax
- Reproduce by laying eggs
Fish- Outer covering of scales
- Have fins to swim and gills to breathe
- Reproduces by laying eggs
- Exceptions: Guppies are fish that give birth to their young alive
Birds- Body covering of feathers
- Feathers keep them warm and help them to fly
- Has a beak, a pair of wings and a pair of legs
- reproduce by laying eggs
Amphibians- live on land and in water
- Breathes through moist skin in water and through lungs when on land
- Reproduces by laying eggs
* A spider is not an insect as it has 8 legs unlike an insect which has 6 legs.
7.Fungi are not plants as they do not make their own food.
8. Some examples of fungi are mushrooms, bracket fungi, puff balls and mould.
9. Fungi reproduce by spores. They feed on other living things,which maybe dead or alive, and which they grow on.
10. Please learn the parts of a mushroom. Spores are found in the gills of mushrooms.
11. Useful fungi- mushrooms can be eaten. Yeast can be used to make bread
12. Harmful fungi- Spoil things when fungi grows on them.
13. Bacteria are microorganisms. They can only be seen under a microscope. They are living things.
- Useful bacteria- They can be used to make cheese and yoghurt.
- Harmful bacteria- They can grow on food and spoil them. Some bacteria make us ill.
Materials
a)Strength – Ability of material to be pulled without breaking or tearing
(b) flexibility- Ability to bend without breaking
(c) Transparency – How much light can pass through
* Transparent materials allows most lightto pass through.
*Translucent material allows little or some lightto pass through
*Opaque materials allows no light to pass through
(d) Ability to float or sink – Whether the object floats or sinks in water
(e) Whether the materials are waterproof –Whether the material absorbs water
We have gone through in class the various tests on how to test each property.
**Please note to answer why the pupils choose a certain material for an object, they need to state the material selected to make the object + the property of the material + how this property is useful for the function or use of the object.
Matter and its states
1) Matter is anything that has mass and occupies space.
Pupils have been advised to use these 2 properties to determine if something is matter.
2) Mass is the amount of matter in a body or object. (measured in g or kg)
3) Electronic balance and beam balance can be used to measure mass.
4) Volume is the amount of space that a body occupies. Measured in cubic cm or cubic m or litres
5) An object has to be removed or displaced before another object can take its place.
6) The three states of matter are solids, liquids and gases.
Solids have definite shape and volume. Liquids have definite volume but no definite shapes. Gases do not have definite shapes and volumes. Only gases can be compressed.
7) Small grains of rice, jelly beans are solids as they have definite shapes and volumes, though collectively when poured into a container, they are seen to take the shape of the container.
8) Please learn the parts of a syringe and how to mark and take the readings.
9) Remember to get accurate readings, bring eye level to meniscus or lowest point of water mark to avoid parallax error.
10) Please look through the steps to find the volume of objects that are irregularly shaped
11) Beakers are not a good measurement tool. Measuring cylinders are better and to pick the most suitable equipment for measurement, look at the volume of the object to be measured and the units of measurement of the measuring cylinder to decide.
12) The three states of water- ice (solid), water (liquid), gas (water vapour)
** To attempt questions on matter, the pupils must identify if the question is asking on mass or volume (occupying space). For Object X to take the place of Object Y, Object Y must be removed or displaced first. Please note that water takes up space and not water level (use water level correctly)
Heat
Heat is a form of energy.
- Sources of heat are things that produce heat like Sun, volcano, candles and light bulbs.
- Heat is also produced by friction (when two objects rub against each other)
- Please use higher temperature or lower temperature. Remember not to use "hotter temperature or colder temperature".
- Clinical thermometer is used to measure body temperature.
- Laboratory themometer is used to measure the temperature of objects and substances.
- Please note that heat and temperature are not the same. Heat is a form of energy while temperature is a measurement of how hot or cold something is.
- Heat will always travel from a hotter to a colder place until they reach the same temperature.
- When an object gains heat, its temperature increases.
- When an onject loses heat, its temperature decreases,
- Matter expand when it gains heat.
-Matter contracts when it loses heat.
Daily use of expansion and contraction
1.A laboratory thermometer contains a liquid such as mercury or alcohol. When the thermometer is placed in something hot, the liquid gains heat and expands. As it expands, it climbs up the scale.
2.Overhead cables are hung loosely so that they do not snap when they contract in cold weather.
3.Railway tracks have gaps along the rails so that the metal rail will not buckle when it expands on hot days.
Good or Poor conductors of heat
Good conductors of heat allow heat to pass through them easily. They allow heat to pass through them quickly.
Poor conductors of heat do not allow heat to pass through them easily.
Metals are good conductors of heat while glass, plastics, wood, rubber and air are poor conductors of heat.
Interesting facts
1.Woollen jackets trap air around your body. As air and wool are poor conductors of heat, heat produced by your body is not easily lost to the surroundings. Thus, wearing a woollen jacket keeps you warm.
2.Metal is not "cold" by nature. If a metal spoon and plastic spoon are placed in an air-conditioned room, they are at the same temperature. The metal spoon feels colder as it is a good conductor of heat and when you touch it, heat is conducted quickly away from our body, faster than the plastic spoon which is a poor conductor of heat. This makes the metal spoon feel colder than the plastic spoon.
3. Uses of good conductors of heat- to make cooking utensils
4. Uses of poor conductors of heat- To make winter clothing and make containers that keep things warm or cold.
** Please note that for heat, please use the following:
- gain heat from XXXXXX
- lose heat to XXXX
***Lastly if the question asks you to explain why you choose an object over some choices, remember to compare by using comparative or superlative adjectives.
