NS:4. UNIT 5: "MATTER AND ENERGY

 

UNIT 5: Matter and energy

5.1.- Matter: mass, volume, and density

- The matter is everything you can see like plants, rocks, and animals.

- Matter has mass, volume, and density.

Ø  Mass

-       Mass is the amount of matter something contains.

-       You can know matter with a balance or scale.

Ø  Volume

-       Volume is the amount of space an object occupies.

-       You can measure volume with a measuring cup and measure cylinder.

Ø  Density

-       Density is the relationship between mass and volume.

-       You have to divide mass by volume.

                                                                                                 D=M

                                                                                                       V

                                                                                                

·       High density.- When there is a large amount of mass and low volume.

·       Low density.- When there is a low amount of mass and large volume.

 

   5.2.-Materials

 

-A material can be one or more types of matter.

- Materials have different properties and different uses.

They can be natural and manufactured.

Ø  Natural materials.-They come from nature: animals ( wool, leather, silk), plants ( cork, wool, cotton), and minerals ( marble, gold). 

Ø  Manufactured materials.- They are natural materials with chemical transformation. Examples: plastic, paper, and steel.

Ø  Properties of materials.- The characteristics of materials are called properties.

·       Colour.- It depends on the light.

·       Hardness.- It refers to how difficult is to change the shape.

·       Resistance.- If it is easy or difficult to break.

·       Elasticity.-If materials can return to their original shape.

·       Thermal conductivity.-If they can transfer heat.

·       Solubility.-If they can dissolve in liquids.

5. 3.-Physical changes

- There are physical changes when the matter can change shape or state.

- They can be reversible or irreversible.

Ø  Change in the state.- A good example is water. It is reversible                                                                  

·       Solidification..- When water becomes solid.

·       Melting.-When water becomes liquid.

·       Evaporation.- when water becomes gas.

·       Condensation.-When water passes from gas to liquid.

Ø  Change in shape.- When the matter is broken. It is irreversible.

5.4.-Mixtures

-        Matter can be:

- Pure substance.-It consists of one type of matter.

- A mixture.-It consists of two or more types of matter.

Ø  Types of mixtures

·       Heterogeneous mixture.-When the different elements are visible and you can separate them. Example: a salad.

·       Homogeneous mixture.- When the different elements are not visible and you cannot separate them. Example:  a milkshake.

Ø  Separating mixtures.- If you want to separate mixtures, you have some techniques.

·       Evaporation.-You can use this method when you want to separate solids from liquids.

·       Filtration.- You can use this method when you want to separate solids from liquids or gases.

·       Distillation.- You can use this method when you can separate two liquids.

·       Decantation.- You can use this method when you can separate liquids from solids.

 

 

5.5.-Energy

-        Energy is everywhere.

-        Energy can also change forms.

 

 

Ø  Forms of energy

·       Mechanical energy.-It  is produced by the movement. Example: cars.

·       Sound energy.-It is produced by vibration. Example: singing.

·       Chemical energy.-It is produced by a chemical reaction between two elements. Example: petrol.

·       Electrical energy.-It makes machines works.

·       Thermal energy.-It flows from warm to cool substances.

·       Light energy.-It is the fastest form of energy. The main source of light is The Sun.

 

5.6.-Sources of energy

Ø  Renewable energy sources.- They are unlimited and they will never run out.

·       Sunlight.-Solar energy is used to generate electricity and to heat water.

·       Water.-Hydropower plants transform water to electricity.

·       Wind.-Wind turbines transform air to electricity.

Ø  Non-renewable energy sources

-       They are limited and they cannot be replaced.

-       They are fossil fuels and uranium.

·       Fossil fuels.- They are coal, oil, and natural gas. They produce pollution.

·       Uranium. It is a radioactive metal in nuclear power stations that produce electricity.

5.7.-Light

-        Light is the fastest form of energy.

-        Light travels through transparent and translucent materials such as glass or plastic but not through opaque such as wood.

-        Light comes from:

o   Natural sources.- The Sun

o   Artificial sources.- Light bulbs. 

Ø  Reflection.- When light hits an object and changes the direction.

Ø  Refraction.- When light passes from one substance into another.

 

5.8.-Heat

-        Heat makes thermal energy where the particles move faster.

-        Thermal energy flows from a warm to a cooler substance.

Ø  Materials and heat

-       Metal transfers heat easily. These types of materials are called thermal conductors.

-       Materials that do not conduct heat are called thermal insulators.

 

 

 

 

NS4: PLANTS AND ANIMALS

 

UNIT 4: Plants and animals

4.1.- Plant classification

Ø  Classification by their stems

·      Grasses.- The stem is thin, soft, and flexible. They don´t have branches.

·      Bushes.- They have a thick and hard stem and low branches.

·      Trees.- They have a trunk, high branches and they are deciduous or evergreen.

Ø  Classification by how they reproduce.        

·      Flowering plants.- They reproduce by seeds.

v Angiosperms..- They reproduce by developing seeds inside the fruit. Examples: roses and rice.

v Gymnosperms.- They reproduce by developing seeds inside cones. Example: pine trees.

·      Non-flowering plants.- They reproduce by spores. Example: mosses and ferns

   4.2.-Reproduction of angiosperms

Ø  Parts of an angiosperm: stigma, stamen, pollen, petal, sepal, ovary, ovule. 

Ø  Pollination

·      Animal pollination.- An animal transfer the pollen from flower to flower.

·      Wind pollination.- The wind blows the pollen from flower to flower.

Ø  Life cycle o fan angiosperm( drawing page 63)

                        1.- Pollen goes into the stigma down to the ovary.

                        2.- A seed develops inside the ovary.

                        3.- The ovary then grows into a fruit with seeds. The petals fall off.

                        4.- The fruit falls, opens, and releases the seeds.

                        5.- The seeds can germinate and new plants grow.

                        6.- The new plant produces flowers.

4. 3.-Plant nutrition and respiration

Ø  Plant nutrition.- Plants make their own food through photosynthesis.

Ø  Plant respiration.- During the day, plants absorb carbon dioxide and expel oxygen. During the night, plants absorb oxygen from the air and expel carbon dioxide.

4.4.-Mammals

-       Mammals are vertebrates. Because they have a backbone.

-       Most mammals have hair or fur.

Ø  Nutrition.- Mammals can be carnivores, herbivores, and omnivores because they have different types of teeth.

Ø  Reproduction.- Most mammals are viviparous which means they are born from their mum´s womb and drink their mum´s milk.

Ø  Respiration.- Mammals breathe with their lungs. Marine mammals such as whales and dolphins breathe through a blowhole.

4.5.-Birds and reptiles

-       Birds are vertebrates. They have wings, beaks, and feathers.

Ø  Birds

·      Nutrition.- They can be carnivores, herbivores and omnivores.

·      Reproduction.- Birds are oviparous which means they are born from eggs.

·      Respiration.- Birds breathe with lungs.

Ø  Reptiles 

-       Reptiles are vertebrates. They have four legs and scales. Some of them have Shell-like turtles.

·      Nutrition.- They are carnivores and omnivores.

·      Reproduction.- They are oviparous.

·      Respiration.- They breathe with lungs.

 4.6.-Amphibians and fish

Ø  Amphibians.- They are vertebrates. They live in fresh Waters or on land near the rivers. They have four legs.

·      Nutrition.- They are carnivores.

·      Reproduction.- They are oviparous. They make adults through the metamorphosis.

·      Respiration.- They offspring breath with gills. Adults breathe with their lungs and with their moist skin.

Ø  Fish.- They are vertebrates. They have scales to protect their bodies. They have a tail and fins.

·      Nutrition.- They are carnivores, herbivores and omnivores.

·      Reproduction.- They are oviparous and lay a lot of eggs at the same time.

·      Respiration.- They breathe with gills. Gills absorb oxygen from the water.

4.7.-Invertebrates

-       Most animals on Earth are invertebrates which means they don´t have a backbone. There are six groups: Arthropods, Molluscs, Echinoderms, Annelids, Cnidarians, and Sponges.

Ø  Arthropods.- Insects, Crustaceans, Arachnids, and Myriapods.

Ø  Molluscs.- Cephalopods, Bivalves, and Gastropods.

Ø  Echinoderms.- Starfish, Sea cucumbers, and Sea urchins.

Ø  Annelids, cnidarians, and sponges. They are the smallest groups.