Standards IE d,,k Students will recognize the usefulness and limitations of models and theories. Students will formulate explanations using logic and evidence
Objective 1 Describe 2 lines of evidence for Earth’s rotation
Objective 2 Explain how constellations show evidence for Earth’s rotation
Objective 3 Explain Earth’s seasons
Assessment Chapter Test
Review Daily Bellwork, Science Starters, Standards Practice
Chapter 26, Section 2
Vocabulary
• Create flashcards and study the following words:– Rotation– Revolution– Perihelion– Aphelion– Equinox– Solstice
The Rotating Earth
• The spinning of the Earth on its Axis is called ROTATION.
• Rotation creates Day and Night• Evidence of Rotation—– Foucault Pendulum– Coriolis Effect– Day and Night
The Revolving Earth
• Earth spins on its axis (rotation) and it also travels or REVOLVES around the sun
• Complete revolution of the sun takes 365 ¼ days.
• Every four years we add a day…leap year• Perihelion=point in orbit closest to the sun• Aphelion =point in orbit farthest from the sun
Evidence of Earth’s Motion
Evidence of Rotation• If you watch the night sky
over a couple of hours, the stars and constellation patterns appear to move in the sky
• The moon and sun also appear to change places in the sky
Evidence of Revolution• Over several weeks a
constellations place in the sky will appear to change and at different times of year, different constellations will be visible.
• See pictures page 669
Measuring Time
• Earth’s motion is the basis for measuring time• One day is 24 hours—the amount of time it
takes Earth to rotate (spin on its axis)• One year is 365 ¼ days –the amount of time it
takes to travel (revolve) around the sun
Calendar
• Ancient civilizations:– Egyptians first to use a solar year– Aztecs used a stone calendar to know when to
plant– Julius Caesar began leap year
• Modern Calendar:– 1500s, Pope Gregory XIII created a calendar to fit
the seasons
AztecMayan
ROMAN
Measuring Time
• Time Zones—24 1 hour periods
Seasons
• Fall and Spring begin on an EQUINOX• Winter and Summer begin on a SOLSTICE• Brain Pop—Seasons and Solstice and Equinox
Interactive/Assessment
• Constellation Project!
INTERACTIVE/Assessment
Use the diagram on page 562 or the one below and copy and label it in your notes.