Untitled Flashcards Set

SCIENCE MID TEST

Chapter 12 Separation Techniques :

- Precipitation : Is a technique by which an insoluble substance is formed in solution by which a chemical reaction. The insoluble substance formed is called precipitate, the liquid left is called supernate.

- Daily aplications :

1. In sewage treatment to remove unwanted things and also bacteria

2. To make pigment and dyes

- Sublimation : Takes a place when solid changes into gas directly without going through liquid stage, sublimation is commonly used to purify substances. Examples in daily applications :

1. Dry ice

2. Insect repellant

- Freeze drying is a complete removal water from food. Examples in daily applications :

1. To preserve food

2. You can find applications food in nugget, frozen food, etc.

Chapter 13 “Force”

There are 3 types of force :

- Gravitational force, exp like :

1. When you are moving down and up stairs

2. The object falls because of gravity exist.

3. The strength of gravity pulls depends between how far they are & the mass of the objects.

- Magnetic force, exp like :

1. Magnet poles (north and south)

2. When a stronger magnet is used, so more stronger the magnetic force

- Frictional force, exp like :

1. When an object moves over a surface, that’s called frictional force

Chapter 14, Simple Machines

Types of simple machines :

1. Levers

2. Pulley

3. Gears

4. Inclined plane

5. Wheel and axle

- Simple machines help us to done our work easier by :

1. Changing the direction

2. Multiplying speed and force

1. Levers, have 3 parts there are :

- Effort (force)

- Load

- Fulcrum

Levers divided into 3 types again, :

1. First class levers : claw hammer, crowbar and a pair of scissors function is to multiply the force to produce greater force

2. Second class levers : Wheel barrow, bottle opener, nutcracker and function is to multiply the force to produce greater force

3. Third class levers : A pair of tongs, broom, fishing rod function is to multiply speed so our work can done faster

2. Pulleys can help us to lift an object, divided into 3 types

- Fixed pulley is to change the direction

- Moveable pulley : pulling the boat to the shore & reduce the force applied

- Pulley systems : block and tackle & multiply the force applied

3. Wheel and axle

- To multiply the force applied

- It is made up of a wheel fixed to the rod called axle.

- Examples like : Pencil sharpener, doorknob, rollercoaster

4. Inclined plane

- To reduce the force applied

- Examples like ramp and staircase

5. Gears, gears are wheel with teeth on them

: Gears to multiply the speed and changing the direction, examples like correction tape

Chapter 15, Sources of the Energy

- Sources of energy :

1. Sun

2. Running water

3. Wind

1. Sun, energy from the sun also called solar energy.

- Plants use light energy from the sun while photosynthesis, the it converts to chemical potential energy

- On the solar panels, light energy from the sun converted into electrical energy

2. Running water

- Hydroelectric power station

1. Gravitational potential energy of water convert into kinetic energy

2. Kinetic energy of water converted into electrical energy

- Wave power station

1. Kinetic energy of waves converted into electrical energy

3. Energy from wind

1. Windmills :

- Convert the kinetic energy of wind to mechanical energy, the mechanical energy is used to grind food.

- Convert the kinetic energy of wind to electrical energy, to generate the electrical energy

2. Wind turbines

- Convert the kinetic energy of wind into electrical energy

4. Energy from fuels

: Examples of fuels are, coal, petrol and gas. When fuels are burnt the chemical potential energy turn into heat and light energy

• Renewable and Non Renewable resources.

- Limited/non renewable such are :

1. Fuels such as coal, oil, petrol, and natural gas

- Renewable

1. Sun

2. Running water

3. Wind

4. Biofuels

Chapter 16, Electricity

- Electricity is used to produce light, heating effect, sound, and magnetic effect

- Light : Such as lamp

- Sound : Such as television and handphone

- Heating effect : Such an oven, hairdryer, heating water

- Magnetic effect : Compass

1. Electromagnet

- Electromagnet is a magnet made using by an electricity.

- Materials that we need for an electromagnet

1. Batteries

2. Wire

3. Sticky tape

4. Iron nail

5. Paper clip

- Factors affecting strength of electromagnet

1. Number of turns of wire in the coil of wire

2. Number batteries used

3. Presence of magnetic materials in the coil of wire

Chapter 17, Structure of The Earth.

- Rocks can be formed beneath or on the surface of the Earth

- There are 3 types of Rocks

1. Igneous (divided into 2)

- Extrusive & Intrusive

2. Sedimentary

3. Metamorphic

1. Igneous

- Extrusive igneous rocks examples : basalt, are formed when lava flows on the surface of the earth and cool and solidifies.

- Intrusive igneous rocks example : granite, are formed when magma or molten rocks cool and solidify beneath the surface of the earth

2. Sedimentary

- Are made up of grains of rocks weathered from a pre-existing rock or mineral

- Examples :

1. Sandstone

2. Limestone

3. Shale

4. Breccias

5. Conglomerate

3. Metamorphic rocks

- Sometimes igneous and sedimentary rocks change their structure because of intense of heat and pressure, when it occurs metamorphic rocks are formed.

- Examples :

1. Marble

2. Slate

3. Schist

- Structure of the Earth

1. Crust :

- The thinnest layer & top layer of the earth

2. Mantle :

- The layer beneath the crust and core, its made up rocks that are in molten state

3. Core

- The hottest layer

- Made up of solid iron and nickel

Chapter 18, Surface of the earth

- Features of the Earth

1. Continent and islands

2. Sea, lakes, oceans, rivers

3. Mountain and hills

4. Deserts, plains, volcanoes, and valleys

- The changing surface of the earth, caused by agents of erosion and weathering. Rain, running water, wind, sunlight (can change the Earth’s surface in many ways such as frost action and thermal expansion), and tidal waves are agents of the erosion and weathering

- The earth’s surface changes due to the processes that can be slow or rapid.

- Slow :

1. Agents of weathering

- Rain, running water, wind, tidal waves, and sunlight

2. Erosion

- Rain, running water, wind, tidal waves

- Rapid

1. Landslides

2. Earthquakes and volcanic eruptions

- Human actions change the surface of the earth, by some activities like :

1. Industrialisation (Logging, mining, dams, road and bridges, factories, power plants and house)

2. Farming

3. Land reclamation

- So how to prevent erosion and landslides?

1. Erosion

- Do not cut down trees unnecessarily or grow trees and plants

- Keep the soil damp during the hot weather by watering it regularly

2. Landslides

- Regrow plants and trees

- Do not cut down trees unneccesarily

- Place a wire mesh over rocks and exposed soil

Chapter 19, Natural Disasters

Examples of natural disasters :

1. Typhoons

2. Volcanic eruptions

3. Earthquakes

4. Tsunamis

- A natural disaster is a result of natural occurrence that affects the Earth’s surface and the surrounding environment

1. Typhoon is a spiral of that forms from warm water

- Typhoons can destroy environment with its strong wind, violent thunderstorm and heavy rain

2. Volcanic eruptions

- Volcanoes are features on the Earth’s surface, it can be found the rim of the Pacific Ocean, in North America and Africa

- An active volcanoes is the one that erupted in the past regularly and will do it again in the future. Ph and Indonesia have so many active volcanoes.

- So, the dangers are :

1. During a volcanic eruption ash, rocks, and lavas are thrown out of the volcano which can cause great damage to the surrounding environment or area

2. There are 3 types of volcanoes

- Active

- Extinct

- Dormant

3. Earthquakes

- Earthquakes usually occur along fault lines, volcanic eruptions also can caused earthquakes

- So, the dangers are :

1. Earthquakes can be extremely dangerous because scientists can not predict where and when it happens, but we can prepare but we can avoid it

2. Also, aftershocks which are the first earthquakes it may happen soon again.

4. Tsunamis

- Is a series of extremely large waves.

- So, the dangers are :

1. Tsunamis carry a lot of energy with them, so when they hit the shore they can destroy anything include you

Chapter 20, The sun And Other Stars

- Sun is the centre of Solar System

1. The sun is a huge sphere that almost occupies the entire Solar System.

2. Sun is made up of hot gases, such are hydrogen and helium

3. Structure of sun :

- Atmosphere

- Photosphere

1. Sunspots

2. Solar Flares

- Core

 The other stars :

- Stars always appears eventhough its day

 Christian and Muslim Calendars

1. Christian Calendar

- It has 365 days / 366 days and it is based on orbit of the Earth around the Sun. Its also called as Gregorian Calendar

2. Muslim Calendar

- Based on the Moon’s orbit around the Earth

- Has 354 days and its also called as Islamic Calendar

Chapter 21, Planets in The Solar System

- There are 8 planets in our Solar System

- They have different characteristics based on temperature, orbit, distance from the sun, period of revolution around the sun

1. Mercury, the closest to the Sun but its not the hottest one

- The distance is 58km

- Temperature is -180 celcius to 430 celcius

- Period of revolution 88 days

2. Venus

- The temperature 465 celcius

- 224,65 days

3. Earth, the distance is 152km

- It has -89 celcius to 57 celcius of the temperature

- 365,25 days it’s the period of revolution

4. Mars

- 228km is the distance from the sun

- -125 celcius to 20 celcius is the temperature

- 687 days

5. Jupiter

- 778 million km from the sun

- 11,2 years is the period of revolution

- -145 celcius to 210 celcius

6. Saturn

- 1427 million km from the sun

- -175 celcius it’s the temperature

- 29,5 years

7. Uranus

- 2870 million km

- -215 celcius

- 84 years is the period of revolution

8. Neptune

- 200 celcius it’s the temperature

- 4497 km million away from the sun

- 164,8 years is the period of the revolution

 Classifying the planets, it can classified by their sizes, composition and distance from the sun.

1. Terrestrial or inner planets, the members are :

- Mercury, Venus, Mars, and, Earth

- They are also known as inner planets

2. Jovian or outer planets

- Jupiter, Saturn, Uranus, Neptune

- They also known as outer planets

 The planets also can classified by presence of planetary rings and presence of moons

 Comets, Asteroids, and Meteoroids

1. Comet is a celestial body that orbits around the sun, when it comes close to the sun it produces visible coma or atmosphere and sometimes a dusty tail

2. Asteroids are thought to be fragment of rocks left over from formation of the Solar System

3. Meteoroids are made up of similar materials like asteroids but smaller than them, meteorites also can create craters on the Earth’s surface, the material come from these craters will cool and solidify and become a tektites

 Benefits and uses of technology

1. Medical and health advancements

2. Engineering

3. Transportation

4. Weather data

5. New materials

6. New source of energy

7. Computer of technology