8th Grade Integrated Science Chapter 12 Lesson 1 on the view of space from earth. This outline worksheet accompanies the Ch 12.1 slides.

1. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page1
Vocabulary
o Spectroscope (417) – an instrument that spreads light into different wavelengths
o Astronomical Unit (418) – the average distance between Earth and the Sun, about 150
million km
o Light-year (418) – the distance light travels in 1 year
o Apparent Magnitude (419) – a measure of how bright it an object appears from Earth
o Luminosity (419) – the true brightness of an object
Looking at the Night Sky
o If you look at the stars for a long time they seem
to________________.
o ________________is a star almost directly above the North
Pole.
o As Earth spins Polaris stays in place as stars near it seem to circle around it.

2. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page2
o Polaris is commonly referred to as the___________________________, because it and the
stars near it never ___________when viewed from the northern hemisphere.
Naked-Eye Astronomy
o Naked-eye astronomy means gazing at the sky using just your eyes; no
___________________ or telescopes.
o Before telescopes, people used the stars to tell time, ___________________, and finding
directions.
Constellations
o When ancient cultures gazed at the night sky, they saw_______________________.
o They represented people, animals, and objects
o The Greek astronomer Ptolemy identified dozens of star patterns
nearly ______________ years ago.
o These are called ________________
____________________today

3. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page3
o Present-day astronomers use many ancient constellations to divide the sky into
______________regions also called constellations
Telescopes
o Telescopes are able to collect much more _____________________than the human eye
o The _______________________ spectrum is a continuous range of wavelengths
o __________________ light is only one part of the spectrum
o Longer wavelengths have ______________energy
o Shorter wavelengths have ______________energy
o Different objects in space can emit different types of wavelengths.
o The range of wavelengths a star emits is called its__________________________.

4. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page4

5. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page5
Spectroscopes
o Scientists study the spectra of a star using a___________________________________.
o A spectroscope ___________________ light into different wavelengths.
o This way, scientists can study a star’s characteristics, compositions, and______________.

Newly formed stars emit mostly _____________and infrared waves. While
exploding stars emit high energy _______________________________waves.

6. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page6
Measuring distance
o Astronomers use angles created by __________________ to measure how far objects are
from Earth.
o Parallax is the apparent change in an object’s
____________________ caused by looking at it from 2
different points.
o
your right eye.
For example: Look at your pencil with only your left eye.
Then, without moving the pencil, look at it with only
o Astronomers create a parallax by using 2 points in Earth’s ____________________ around
the Sun

7. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page7
Distance Within the Solar System
o Distances ________________ the solar system are measured using astronomical units or
AU.

An astronomical unit is the average distance between Earth and
_____________________ , about 150 million km.
Distances Beyond the Solar System
o Astronomers measure distances ___________________ the solar system using light-years.
o A light-year is the distance light travels in 1 year.
o 1 light-year equals about 10 _______________________km.

The nearest star to our Sun is 4.2 light-years away. How far is that in km?
Looking Back in Time
o Because it takes time for light to travel, you see a star not as it is______________, but as it
was when light left it.
o At 4.2 light-years away, Proxima Centauri appears as it
was ______________ years ago.
Measuring Brightness
o Astronomers measure the brightness of stars in two ways:

8. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page8
o By how bright they appear from Earth
o By how bright they actually are
Apparent Magnitude
o Scientists measure how bright stars appear from __________________ using a scale
developed by the ancient Greek astronomer Hipparchus
o Hipparchus assigned a _______________ to every star he saw in the night sky based
on its brightness.
o Today these are called __________________ _____________________
o The apparent magnitude of an object is a measure of how bright it appears from
Earth

Hipparchus assigned the number __________ to the brightest star he saw in the
night sky
Absolute Magnitude
o Stars can appear bright or dim depending on their __________________ from Earth, but
stars also have actual, or absolute, magnitudes
o __________________________is the true brightness of an object
o This depends on the star’s _____________________and size rather than its distance from
Earth

9. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page9
o A star’s luminosity, distance, and apparent magnitude are all_____________________.
Thus, if a scientist knows two of these factors, he can mathematically determine the third.
Apparent Magnitude Scale

10. Chapter 12 Lesson 1 – The View from Earth – p414-419 - page9
o A star’s luminosity, distance, and apparent magnitude are all_____________________.
Thus, if a scientist knows two of these factors, he can mathematically determine the third.
Apparent Magnitude Scale