+ Unit 5 Lesson 1 The Solar System

+ What is the Sun? Big Idea

+ Anticipatory Set

+ Science Standard 5.a Students know the sun, an average star, is the central and largest body in the solar system and is composed primarily of hydrogen and helium.

+ Science Standard 6.b Develop a testable question

+ Input Star: A huge ball of very hot gases in space Sun: The star at the center of the solar system Fusion: The energy-producing reaction that occurs inside stars

+ Input – Stars (pg. 332) The sun is the source of most energy on Earth. Life on Earth would not exist without it. It is composed of mostly helium and hydrogen. The sun is responsible for wind and other weather on Earth. It is one of many stars and is a medium sized star.

+ Input – Stars (pg. 333) Star colors range from blue, white and yellow to orange and red. Color is a clue to the surface temperature. The sun is a yellow star with medium surface temperature. The sun is considered an average bright star and is the closest start to Earth.

+ Input – Features of the Sun (pg. 334) The sun has several layers without definite boundaries. The core is at the center of the sun and is small compared to the entire sun. However, most of the mass is in the core. Energy from the core moves outward through the radiation zone. This movement heats this layer.

+ Input - Features of the Sun (pg. 334) The energy then moves to the sun’s outer layer called the convection zone. Energy moves to the surface through a process called convection. This is when cooler, denser matter is pulled down by gravity, pushing warmer, less dense matter up. The surface of the sun is called the photosphere. Above the photosphere is the atmosphere of hot gases.

+ Input – How the Sun Produces Energy (pg. 336) The sun’s energy comes from fusing, or combining, small particles into larges ones. The center of the sun is 15 million °C. This amount of heat and enormous pressure causes hydrogen atoms to smash into each other and produce helium. This causes the sun to release energy as light and heat. This is called fusion because two hydrogen nuclei fuse to produce one helium nucleus.

+ Input – How the Sun Produces Energy (pg. 336) This energy travels in waves, some having more energy than others. This range of energy is called the electromagnetic spectrum. Some energy is seen as visible light, some felt as infrared heat. The sun also produces radio waves.

+ Summary A star is a giant ball of gas. The sun on earth is considered one of many stars and is of average size and brightness. The sun produces energy for all of earth. The energy is produced through convection and fusion. The energy is then released through waves. This is seen on the electromagnetic scale with visible light, infrared waves, and radio waves.

+ Unanswered Questions How might a huge wave of energy affect the earth? Create 2 more (You must have 3 written down).

+ Ethics The Earth’s atmosphere is protecting us from harmful radiation waves of energy from the sun. Pollution from our cars and other aerosol products are creating a hole in the atmosphere. What can you do to help stop pollution from destroying our atmosphere?

+ Modeling What is it called when two hydrogen nuclei fuse together to create one helium nucleus? Fusion How hot is the center of the sun? 15 million °C

+ Check for understanding What is the process of energy being released from the core? Convection

+ Check for understanding What is the surface of the sun called? Photosphere