Term 2 Notes

1. Term 2 Notes

2. The image above is the sun. The sun is a massive star which its at the center of our solar system. The sun has a diameter of nearly 1.4 million kilometres. It has a surface temperature of 15 000 000 °C It is estimated that the sun has been burning for about 4.6 billion years and has enough fuel for another 5 billion years. Eventually the sun will burn itself out. However, this process will take a trillion years

3. The Solar System The solar system is made up of a star and all the celestial bodies (planets, meteors, asteroids, etc.) that surround it. There are eight planets in the solar system. The first four Mercury, Venus, Earth, Mars are known as terrestrial planets. Jupiter, Saturn, Uranus, Neptune are known as gas giants. They are far larger than the terrestrials.

4. There are smaller planets like Pluto, Ceres, and Eris that are known are dwarf planets. Furthermore, asteroids and meteors are much smaller than dwarf planets. Some of the larger planets have moons attached to them. Earth has one. However, some of the larger planets like Jupiter have 16 moons, Saturn has 18 and Uranus has 15. Moons vary in size between 10 and 3000km

5. Terrestrial Planets The four terrestrial planets are Mercury, Venus, Earth, Mars. These planets are mostly made up of rock and have a solid surface. They also have the same internal structure: a metallic core, a liquid mantle and a crust. These planets also have an atmosphere made up of different gasses.

6. Gas Giants The four larger planets are known as gas giants; Jupiter, Saturn, Uranus, Neptune The internal structure of these planets are relatively unknown. We do know that these planets have a solid core and a very dense atmosphere. There is no solid outer crust. Instead thick layers of very hot or cold gases surround the solid core.

7. Asteroids Asteroids are small pieces of rock that orbit the sun. They are sometimes referred to as minor planets. Asteroids measure from 10 to almost 1000 kilometres. The composition of asteroids are; a solid rock core and a surface of ice and rock. There is an entire belt of asteroids that surrounds the sun.

8. Comets Comets are small masses of ice and rock. Comets are usually small from about 1 to 20km. Their most distinctive feature are the tail. The tail is a mixture of rock, gas, dust and ice which is reflecting light from the sun. This reflection allows us on Earth to track the movement of comets. Comets have very large orbits.

9. Most comets are only visible every couple of years. Some only appear every 100 years. The tail of the comets always point away from the sun. Most comets have a blue color to their tail. This is the result of the ultraviolet light and the fluorescent particles present in the dust.

10. Meteors A meteor is a sand to boulder sized piece of debris present in the Solar System. When this debris is still free moving within the Solar System it is called a meteoroid. As soon as a meteoroid enters the Earth’s atmosphere it is called a meteor. If a meteor falls to the surface of a planet and survives the impact it becomes a meteorite.

11. What makes our Planet Different from others?

12. The only known planet that has life. Has a large supply of oxygen. Large supply of water. A protective ozone layer How would you describe our planet to someone or something who has never seen it before? What are some of the Earth’s properties?

13. Internal Structure of the Earth The Earth is made up of four layers. Crust Mantle Outer Core Inner Core The Earth also has an exterior structure called the atmosphere.

14. Earth’s Structure: Crust For all living organisms the crust is the most important part of the Earth. The crust houses all life present on Earth. The crust of the Earth is between 5-50km thick. The thinnest parts of the crust are the ocean floors, the thickest are mountain chains. The crust sits on top of the mantle. The mantle is liquid.

15. The crust is not all one solid piece. Over time it has broken into smaller pieces. These pieces are called tectonic plates. The crust has all of the properties that life needs to survive. It experiences changes in temperature, weather, and precipitation. It is the part of the Earth that is most effected by Global warming. It is also effected by pollution created by humans.

16. The Mantle The second layer of the Earth is the Mantle. The mantle is the thickest layer of the Earth. It extends to a depth of over 2800km. This layer is made up of liquid rock. There is incredible pressure and heat that forms in this layer.

17. The Crust floats on the top of the mantle in giant pieces called tectonic plates. These plates move around and cause earthquakes and volcanoes. The mantle is constantly in motion. This movement causes the tectonic plates scrape and hit each other, which is an earthquake. Volcanoes form when two plates crash into each other. Volcanoes are the earth’s cooling system and pressure release.

18. The Core The core is the innermost layer of the Earth. It is usually divided into outer core and inner core. Although there is no confirmed theories the most probable is that the outer core is liquid metal mostly iron and nickel. With this theory scientists argue that the core is a solid ball of iron.

19. The core is the heaviest layer of the earth. It is believed that this layer gives the earth it’s gravity and magnetism. Magnetism is a force. It is this force that causes compass needles to point north. This is what we call magnetic north.

20. Hydrosphere The hydrosphere refers to the layer of water that surrounds the Earth. 71% of the Earth’s surface is covered by water. Most of this is found in the Earth’s oceans and seas. The hydrosphere is home to millions of plant and animal species. The hydrosphere includes oceans, lakes, rivers, streams, as well as ice and glaciers.

21. Water vapour and clouds also make up part of the Hydrosphere. The hydrosphere is responsible for the hydrologic cycle also called the “Water Cycle”. This cycle is what gives us precipitation. Water will evaporate and form into clouds, when clouds contain too much water it is released as precipitation (rain, hail, sleet, snow). This process is vital for all life on earth. Every living thing needs water to survive.

22. Aurora Borealis Otherwise know as the Northern Lights. These lights happen naturally and are only visible in the far north. The closer you are to the magnetic north pole the better you will see these lights. These lights usually appear around the equinoxes. Equinox: when the day and night are equal.

23. There is a second set of lights in the south. These are more rare than those in the north. The southern lights are called Aurora Australis. The lights are caused by light particles being attracted by the Earth’s magnetic field and mixed with solar wind. Oxygen and nitrogen as also present. When more oxygen is present the lights are green, more nitrogen means the lights are blue.

24. The Moon The Moon is approximately 3500 km in diameter and is roughly 385 000 km from Earth. To date there has only been one manned lunar landing (1969 by the US). But this has raised controversy over the years. It is believed that the moon was created due to a large asteroid impact. Today scientists have discovered water on the moon.

25. It is believed that the moon has a similar structure to that of the Earth. Which consists of a thick crust, fluid mantle and outer core, and a solid inner core. It takes roughly 29 days for the Moon to orbit the Earth. The surface of the moon is completely covered with craters. This is due to meteoroid impact. Many more meteor hit the surface due to the lack of a thick atmosphere.

26. Phases of the Moon The Moon itself does not give off any light. The Moon’s surface reflects light from the Sun, this is due to the composition of the rocks. Many of the rocks on the Moon have reflective properties. It is this property that allows us to see the moon at different times of the month.

27. As the Moon orbits the Earth different amounts of sunlight will hit it’s surface. This will allow us to see the moon in different shapes. In a 29 day cycle we see a full moon once, on day 14. This is because the sun is hitting the surface facing the Earth. At day 0 and 29 it is “new moon” this is when it is not visible since light is hitting the surface away from the Earth. Crescent, Half, and Gibbous moons are spaced throughout the 29 days.

28. Eclipses An eclipse occurs when one celestial body moves in front or through the shadow of another. Our eclipses include three celestial bodies; the sun, Earth, and the moon. There are two types of eclipses that we may experience. Solar eclipse Lunar eclipse

29. Lunar Eclipse This eclipse occurs when the moon passes behind the Earth. Therefore, the Earth is blocking almost all the sun’s light.

30. Solar Eclipse A solar eclipse occurs when the moon passes in front of the sun. In this case the moon blocks out the light of the sun. Starring at a solar eclipse for an extended period of time could result in eye damage.

31. Day-Night Cycle The Earth revolves around the sun. This process takes 365 ¼ days (1 year). At the same time the Earth is rotating. This takes 24 hours. The part of the Earth that is facing the sun is experiencing day. The part of the Earth that is away from the sun is experiencing night.

32. Seasons Our Earth like other planets rotate. Every planet rotates on an axis. The Earth’s axis is not perfectly straight it is tilted 23.5° Just like the cycle of day and night, seasons occur in cycles. At different times of the year different parts the earth experience the seasons differently.

33. When countries experience winter when they are tilted away form the sun. Summer occurs when the country is tilted towards the sun. During winter there is less solar radiation and light that hits that part of the Earth. Less radiation and light means there is less heat. Which means temperatures are a lot lower (colder). During summer time there is more light and radiation. Therefore, warmer weather

34. Drawings Drawings, images, and pictures are used in our everyday lives. Drawings can be used to represent an event, action, person, or a law. In many circumstances a drawing or picture can be clearer than a verbal or written explanation. Some images have become so recognizable that no words are needed at all.

35. Types of Drawings Drawings are most often used in construction. Drawings serve to illustrate how various parts will connect with one another. Furthermore, drawings will show dimension. Finally a drawing can depict how to put an object in motion.

36. Drawings can also serve as instructions in the making of a technical object. There are three types of drawings one can use. 1) Sketch A sketch is a freehand drawing that depicts a design of an object. It will show the shape and some dimensions of an object. It will also help in the creation of other drawings

37. 2) Design Plan A simplified drawing showing the function and operating principles of an object. This type of drawing does not include any measurements or list of materials.

38. 3) Technical Drawing Is a simplified drawing showing the materials and steps to get the object to its final functioning form. It may also be necessary to include several angles (front, top, side views) This type of drawing also includes how different pieces will be connected. There are 12 basic lines that one can use in a technical drawing

39. Manufacturing Process Sheet A manufacturing process sheet is a document similar to a set of instructions. This document includes every step required to manufacture a technical object. It provides the order in which steps need to be carried out. It also gives the time allotted for each step

40. Materials, Raw Materials, and Equipment The manufacturing of technical objects requires a diverse set of materials. Material: any substance used to make things. Materials are classified by the origin of their raw materials. Materials include things like: wood, glue, staples, paper, metals, etc.

41. Raw materials: a natural material that has not been transformed into materials that can be used. Raw materials are unprocessed. There are three major categories of raw materials. Wood substances: hard and soft wood Minerals: Iron, copper, steel, etc. Crude oil: plastic, polymer, nylon, etc.

42. Equipment: are the tools, instruments, and machines that create technical objects. Equipment could be as simple as a pencil, scissors, toothpick, etc. Equipment are technical objects themselves. Every piece of equipment is made up of materials and followed a process in its manufacturing.

43. Specifications Specifications is a document that provides a detailed description of needs and demands. A technical object will have a specific function, therefore it needs to be built in a certain way. For example, a bridge must be able to withstand strong winds, precipitation, and natural hazards.