Sec 1 - Chapter 2 and 3

The Size of the Solar

System

Radar

• The first known radar was built in 1935.

• It emitted mircowaves which allowed us to

determine the distance to an object by timing how

long it takes for the microwave to be reflected

back to source.

• Radar lets us determine the size of celestial

bodies and their distance from us.

• Bats use radar to locate obstacles and prey.

• Bats produce a particular sound and then listen for

its echo.

• We cannot hear a bats “radar” sound

The Solar System:

Like a Grain of Sand on the

Beach

Read page 25 together.

What is the speed of light?

• 300 000 km/s or 300 000 000 m/s

• This is how far light goes in one year:

• Our galaxy is called the Milky Way.

• What is a galaxy?

• A group of stars and other celestial bodies.

• The Milky Way is over 100 000 light years wide!!

• How long does light from the Sun take to reach

the Earth?

• 8.3168708 minutes.

• Rounded off, let's say 8 minutes and 18

seconds.

What happened to the space

shuttle, Columbia?

• Exploded during takeoff on February

1, 2003.

• By recovering debris from the space

shuttle and analyzing the debris they were

able to identify which part of the space

shuttle exploded.

The Experimental Method

• Galileo built his telescope in 1606. He was the first

to use it to observe the sky.

• Things he discovered:

• Saturn’s Rings

• Jupiter’s satellites

• The Phases of Venus

• And much more!!

• His observations of Venus proved

that the Earth travelled around the

Sun.

• His telescope made these

observations possible.

• By improving technology, we are

able to continue improving

scientific knowledge.

• We will read pages 433 - 435

How to Apply the

Experimental Method

• There are 5 steps:

1. I observe…

2. I develop a research question…

3. I define the variables…

4. I experiment…

5. I analyze my results and present them>

The Solar System:

Like a Grain of Sand on the

Beach

Read page 25 together.

What is the speed of light?

• 300 000 km/s or 300 000 000 m/s

• This is how far light goes in one year:

• Our galaxy is called the Milky Way.

• What is a galaxy?

• A group of stars and other celestial bodies.

• The Milky Way is over 100 000 light years wide!!

• How long does light from the Sun take to reach

the Earth?

• 8.3168708 minutes.

• Rounded off, let's say 8 minutes and 18

seconds.

The Sun

• The closest star to the Earth.

• A ball of gas made primarily of hydrogen (H)

• The Sun is 5770 °C on the surface

• The Sun is 15 000 000 °C at the center!

• The Sun is part of our

galaxy, the Milky Way

• What is a galaxy?

• A group of planets and

other celestial bodies.

• The Sun acts like a huge nuclear reactor turning

hydrogen (H) into helium (He).

• It is thought the Sun will be active for another 5

billion years.

• At this time, the Sun’s diameter will increase and it

will swallow the Earth!!

• It will be 2000 °C on Earth.

• Then the Sun will cool and die.

Ambulance Sirens

• The Doppler Effect is what we hear as the

s]ambulance gets closer and then moves away.

• The siren seems to become more high pitched as

the ambulance gets closer and less high pitched

as it moves away.

• Why?

• Shall we listen?

• Sound waves move like waves on the water.

• As the waves move away from the point of contact

the space between the waves becomes larger.

• This means they are more spread out in the air.

• As the sound waves get farther apart the sound

has a lower pitch.

• The Doppler Effect and light waves

• Light waves also create circular waves

• Light waves that are close together correspond to

violet light.

• Light waves that are farther apart are correspond

to red light.

• As the planets

move farther

away, they

become “red”

• How can we remember the order of the colors?

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