Unit 2 Lesson 1 What Are the Sun and Stars? Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Are the Sun and Stars? Florida Benchmarks SC.3.E.5.1 Explain that stars can be different; some are smaller, some are larger, and some appear brighter than others; all except the Sun are so far away that they look like points of light. SC.3.E.5.2 Identify the Sun as a star that emits energy; some of it in the form of light. SC.3.E.5.3 Recognize that the Sun appears large and bright because it is the closest star to Earth. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Are the Sun and Stars? Florida Benchmarks SC.3.E.5.5 Investigate that the number of stars that can be seen through telescopes is dramatically greater than those seen by the unaided eye. SC.3.E.6.1 Demonstrate that radiant energy from the Sun can heat objects and when the Sun is not present, heat may be lost. Copyright © Houghton Mifflin Harcourt Publishing Company

A Tale of Two Stars The Sun Unit 2 Lesson 1 What Are the Sun and Stars? A Tale of Two Stars The Sun On a clear night, you can see many stars in the sky. Our sun is a medium-sized star. Our sun appears much larger and brighter than other stars. That is because it is much closer to Earth than other stars. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Are the Sun and Stars? A star is a ball of hot, glowing gases. The sun, like other stars, gives off light and heat. The sun and other stars are present in the daytime. You cannot see the other stars because the sun makes the sky so bright. Copyright © Houghton Mifflin Harcourt Publishing Company

Great Balls of Fire From far away, stars look very similar. Unit 2 Lesson 1 What Are the Sun and Stars? Great Balls of Fire From far away, stars look very similar. Up close, stars have many different characteristics. Stars can be different sizes, colors, and brightnesses. Copyright © Houghton Mifflin Harcourt Publishing Company

Great Balls of Fire Brightness tells how much light a star gives off. Unit 2 Lesson 1 What Are the Sun and Stars? Great Balls of Fire Brightness tells how much light a star gives off. Some stars are bright and give off a lot of light. Some stars are dim. They do not give off much light. Copyright © Houghton Mifflin Harcourt Publishing Company

Great Balls of Fire Space is filled with different sizes of stars. Unit 2 Lesson 1 What Are the Sun and Stars? Great Balls of Fire Space is filled with different sizes of stars. Supergiant stars are the largest stars. Hundreds or thousands of our sun could fit inside one supergiant. The smallest stars are called white dwarfs. Copyright © Houghton Mifflin Harcourt Publishing Company

Great Balls of Fire Stars have different colors. Unit 2 Lesson 1 What Are the Sun and Stars? Great Balls of Fire Stars have different colors. Our sun is a yellow star. Other stars are blue, white, or red. Blue stars are the hottest. Red stars are the coolest. Copyright © Houghton Mifflin Harcourt Publishing Company

Full of Energy The Sun Lights Earth Unit 2 Lesson 1 What Are the Sun and Stars? Full of Energy The Sun Lights Earth Stars, including the sun, give off radiant energy. Radiant energy is energy that can travel through space. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Are the Sun and Stars? The Sun Lights Earth Some of the sun’s radiant energy travels to Earth as light. Light energy helps people and animals see. Plants use light energy to make their own food. Without the sun, there would be no plants or animals on Earth. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 1 What Are the Sun and Stars? The Sun Heats Earth Radiant energy from the sun also warms Earth’s land, air, and water. Without the sun’s radiant energy, Earth would be very cold. You cannot see the sun’s energy heating Earth, but you can feel it. When you walk on a beach heated by the sun, the sand feels hot. Copyright © Houghton Mifflin Harcourt Publishing Company

Stargazing You can see more stars at night if you have a telescope. Unit 2 Lesson 1 What Are the Sun and Stars? Stargazing You can see more stars at night if you have a telescope. A telescope is a tool that makes faraway objects seem larger and closer. A telescope also makes stars look brighter. Copyright © Houghton Mifflin Harcourt Publishing Company

Stargazing Remember: Never look directly at the sun! Unit 2 Lesson 1 What Are the Sun and Stars? Stargazing Remember: Never look directly at the sun! Copyright © Houghton Mifflin Harcourt Publishing Company