The Sun: An Important StarThe Sun: An Important Star14.714.7

The Sun’s Affects on the The Sun’s Affects on the EarthEarth

The Sun is the only star in our solar The Sun is the only star in our solar system. system.

It gives the energy needed by all It gives the energy needed by all the Earth’s plants and animals.the Earth’s plants and animals.

Its gravitational pull keeps us in our Its gravitational pull keeps us in our steady orbit.steady orbit.

1.1. No life could exist on any planet No life could exist on any planet in our solar system without the in our solar system without the energy provided by the Sun.energy provided by the Sun. P.452P.452

At night, the temperature drops, At night, the temperature drops, the light fades, and other objects the light fades, and other objects become visible.become visible.

Because the Sun is the closest star Because the Sun is the closest star to the Earth, you cannot see to the Earth, you cannot see other stars until the Sun has set.other stars until the Sun has set.

Where does the Sun’s Where does the Sun’s Energy come from?Energy come from?

The Sun produces energy through a The Sun produces energy through a process called process called 2.2.Nuclear Fusion -Nuclear Fusion -Hydrogen nuclei fuse to form helium Hydrogen nuclei fuse to form helium nuclei. nuclei.

Inside the Sun the temperature and Inside the Sun the temperature and pressure are so high that substances pressure are so high that substances fuse and form new substances. fuse and form new substances.

3.3.When the substances fuse together it When the substances fuse together it produces large amounts of heat, produces large amounts of heat, light, and other energy that travel light, and other energy that travel from the Sun into space.from the Sun into space.

Nuclear FusionNuclear Fusion

Hydrogen nuclei fuse to form helium Hydrogen nuclei fuse to form helium nuclei.nuclei. This process produces large This process produces large amounts of heat, light, and other amounts of heat, light, and other energy that travel from the Sun into energy that travel from the Sun into space. space.

4.4.The Sun is about 75% hydrogen and The Sun is about 75% hydrogen and 25% helium.25% helium.

paragraphs paragraphs 3-43-4

Nuclear PowerNuclear Power(Point Lepreau in St. John)(Point Lepreau in St. John)

5. 5. Nuclear power plants do this to create Nuclear power plants do this to create energy for homes, but on a much smaller energy for homes, but on a much smaller scale.scale. They use tiny amounts of a metal They use tiny amounts of a metal called called uraniumuranium to start a nuclear reaction. to start a nuclear reaction.

The reaction releases heat, which is used to The reaction releases heat, which is used to make steam.make steam.

Nuclear power plants don’t pollute the air, Nuclear power plants don’t pollute the air, but their waste is very dangerous.but their waste is very dangerous.

A nuclear accident can poison a large area A nuclear accident can poison a large area for thousands of years.for thousands of years.

ActivityActivity

On a blank sheet of paper draw a On a blank sheet of paper draw a picture similar to Figure 3 on p.453.picture similar to Figure 3 on p.453.

It should look like a “Black Line It should look like a “Black Line Master” drawing, making sure the Master” drawing, making sure the lines for the labels are all lined up lines for the labels are all lined up and neat.and neat.

Label all the parts of your drawing.Label all the parts of your drawing. Do questions 1, 2, 7 on p. 453. Do questions 1, 2, 7 on p. 453.

Fig. 3Fig. 3Page Page 453453

P. 453 QuestionsP. 453 Questions

1.1. Describe the difference between a Describe the difference between a solar flare and a solar prominence. solar flare and a solar prominence. Which affects us and how?Which affects us and how?

A solar flare is an eruption of hot gases A solar flare is an eruption of hot gases from the inner atmosphere of the from the inner atmosphere of the Sun’s surface. It travels very quickly Sun’s surface. It travels very quickly and last for only minutes.and last for only minutes.

A solar prominence is a burst of a huge A solar prominence is a burst of a huge

sheet of gases, also from the inner sheet of gases, also from the inner atmosphere. It is much larger than a atmosphere. It is much larger than a flare and may last for days or even flare and may last for days or even weeks.weeks.

The charged particles from a solar The charged particles from a solar flare affect us in two main ways: flare affect us in two main ways: They produce the beautiful auroras, They produce the beautiful auroras, and they cause problems in and they cause problems in communication systems.communication systems.

2.2. Describe the process that occurs in Describe the process that occurs in the Sun’s core to produce so much the Sun’s core to produce so much energy.energy.

The process is called nuclear fusion. The process is called nuclear fusion. Inside the Sun it is so hot and the Inside the Sun it is so hot and the pressure is so high that the pressure is so high that the substances actually fuse together to substances actually fuse together to form new substances.form new substances.

7.7. Why do we consider the Sun to be Why do we consider the Sun to be the most important star?the most important star?

The Sun is the most important star to The Sun is the most important star to us because it provides the light us because it provides the light energy and heat needed to support energy and heat needed to support life on Earth (us). life on Earth (us).

Tomorrow we will watch a video: Tomorrow we will watch a video: TLC – TLC – StarsStars Episode 1 Episode 1