8U3L6 Seasons Introduction

Seasons Introduction

8.MS-ESS1-1b. Develop and use a model of the Earth-Sun system to explain the cyclical pattern of seasons, which includes Earth’s tilt and differential intensity of sunlight on different areas of Earth across the year.

Essential Questions

• What causes day and night?

• What causes the seasons to change?

Open Ended

What is your favorite season and why?

Rotation

• Rotation is a turning or spinning on an axis

• An axis is the imaginary line that runs through both poles of the earth

Earth's Rotation

The earth rotates (turns) one time every 24 hours

Multiple Choice

Each time the earth rotates, we have one...

• hour

• day

• month

• year

Revolution

A revolution is one object moving completely around another in an orbit path

Earth's Revolution

The earth revolves around the sun one time every 365.25 days.

Multiple Choice

Each time the earth revolves around the sun, we have one...

• hour

• day

• month

• year

Hemispheres

• The earth is divided into two equal halves called hemispheres

• The Northern Hemisphere is located above the equator

• The Southern Hemisphere is located below the equator

• The northern and southern hemisphere experience opposite seasons.

Fill in the Blanks

Multiple Choice

Which hemisphere do we live in?

• Northern Hemisphere

• Eastern Hemisphere

• Southern Hemisphere

Why do seasons happen?

• Instead of spinning straight up and down like a top, the earth is tilted 23.5 degrees

• When a hemisphere is tilted toward the sun it is warmer, and when it is tilted away from the sun it is colder

Multiple Choice

The Earth tilts at ______

• 90°

• 23.5°

• 56.2°

• 24°

Open Ended

Why do you think it is warmer here when the northern hemisphere is tilted toward the sun?

People often think that when a hemisphere is tilted toward the sun it is warmer because it is closer to the sun...

That's wrong!

It's actually because of the energy in direct and indirect light!

• Direct light shines its energy on a small spot - giving its radiation ALL to a SMALL area.

• Indirect light spreads its energy - giving the same amount of energy to a bigger area (each spot in that area gets less energy!)

Direct & Indirect Light on the Earth

• When the hemisphere is tilted toward the sun, it receives direct light and is warmer

• When the hemisphere is tilted away from the sun it receives indirect light and is colder

Multiple Choice

What effect does the tilt of the earth have?

• It causes the earth to be farther away from the sun at different times of the year

• It changes the angle that the sun strikes the earth in different land areas

• When the earth is tilted away from the sun we have day

• When the earth is tilted away from the sun we have night

Multiple Choice

Why is it warmer in the summer?

• Closer to the sun

• More direct light from Earth's tilt

• Stronger light from the sun

• Earth spins slower

Multiple Choice

Why is the Equator warmest?

• Because it is closest to the sun.

• Because it receives the most direct sunlight

• Because no clouds form here.

• Because it is far from the sun

Seasons

• Summer - when the hemisphere is tilted TOWARDS the sun. Longer days, shorter nights, and the warmest season.

• Winter - when the hemisphere is tilted AWAY from the sun. Shorter days, longer nights, and the coolest season.

What about Spring and Fall?

• Autumn (Fall) -from summer to winter - the days get shorter and the weather gets colder

• Spring - from winter to summer the days get longer and the weather gets warmer

The seasons always go in this order:

• Winter

• Spring

• Summer

• Fall

Because of the tilt of the earth, when it is one season in the northern hemisphere it is the opposite season in the southern hemisphere.

• Summer - Winter

• Spring - Fall

Multiple Choice

What happens when the area in which you live tilts away from the sun?

• It is winter

• It is summer

• It is spring

• It is fall

Multiple Choice

What season is it in the Northern Hemisphere when it is fall in the Southern Hemisphere?

• Winter

• Spring

• Summer

• Fall

Multiple Select

Which two of the following best describes the tilt of the earth when it is summer in the southern hemisphere?

• The northern hemisphere is tilted toward the sun

• The northern hemisphere is tilted away from the sun

• The southern hemisphere is tilted toward the sun

• The southern hemisphere is tilted away from the sun

Multiple Choice

If it's summer in the Northern hemisphere, then it's ______ in the Southern hemisphere.

• spring

• summer

• fall

• winter

Multiple Choice

Last Question! ____ comes before Winter

• summer

• spring

• fall

Write your vocabulary in your notebook!

• axis - the imaginary line that extends from the North Pole to the South Pole and is the center of the Earth’s rotation

• direct - going in a straight line without turns or interruptions

• equator - the imaginary line around the Earth that is the same distance from the North and South Poles

• hemisphere - half of the Earth’s sphere

• indirect - not going in a straight line

More Vocabulary Words...

• orbit - the circular path something (like a moon or planet) follows as it travels around something else

• rotate - the spin the Earth makes on its axis

• revolution - the movement of one object around another

• season - one of the four quarters into which the year is usually divided, beginning at an equinox or solstice

• tilt - the slant of the Earth’s axis (23.5 degrees from vertical)