Planet Earth Part One: The Measurement of Time

The planet we live on is called Earth.

It is one of nine planets in our Solar System.

The word Solar means, “of or having to do with the sun.”

These nine planets orbit around the sun.

Each orbit equals one full trip around the sun.

Notice that the Earth’s orbit around the sun is not a perfect circle.

Earth’s orbit around the sun is called an “elliptical” orbit because it does form a perfect circle.

There are two points in Earth’s orbit of the sun that are significant.

They are the “Perihelion” and the “Aphelion”

“Perihelion” comes from two words, “ Peri” meaning around and “Helios” meaning sun.

The “Perihelion” is the point in Earth’s orbit when it comes closest to the sun.

Aphelion is made up from two words, “Apo” meaning from and “Helios” meaning sun.

The “Aphelion” is the point in the Earth’s orbit when it is furthest away from the sun.

When do you think we experience our summers, when we are at the Perihelion or the Aphelion?

You’re right! We experience summer when the Earth is at aphelion.

Even though the Earth is at the point farthest from the sun our hemisphere is tilted towards the sun and we receive more direct sunlight.

We experience our winter season when Earth is at it’s perihelion because our hemisphere is tilted away from the sun and we receive less direct sunlight.

We call the time it takes the Earth to complete an orbit around the sun a year.

There are twelve months in our year.

Four Seasons in our year: Summer, Fall, Winter, and Spring.

There are three hundred and sixty- five days in our year.

We have fifty-two weeks in our year 52

Each week has seven days

Each day has twenty-four hours.

Each hour has sixty minutes.

Each minute has sixty seconds.

Are there any questions?

1.) What planet do we live on? a.) Mercury b.) Saturn c.) Earth d.) Pluto

2.) How many planets are in our solar system? a.) Nine b.) Seven c.) Twelve d.) Five

3.) What does the word “Solar” mean? a.) Soul b.) Son c.) Sold d.) Sun

4.) The nine planets in our Solar System orbit around the? a.) Middle b.) Son c.) Sun d.) Center

5.) Each orbit equals ? a.) One trip around the track. b.) One trip around the world. c.) One trip around the sun. d.) One trip to the principal’s office

6.) Is Earth’s orbit around the sun a perfect circle? a.) Yes b.) No c.) I don’t know

7.) The shape of Earth’s orbit is called…? a.) Circular b.) Eclipse c.) Square d.) Elliptical

8.) The prefix “peri” means: a.) Sun b.) From c.) Around d.) At the side of

9.) The prefix “apo” means: a.) Sun b.) From c.) Around d.) At the side of

10.) The prefix “helios” means: a.) Sun b.) From c.) Around d.) At the side of

11.) The point in the Earth’s orbit when it comes closest to the sun is called? a.) Bellerophon b.) Periodontist c.) Aphelion d.) Perihelion

12.) The point in the Earth’s orbit when it is farthest from the sun is called? a.) Bellerophon b.) Periodontist c.) Aphelion d.) Perihelion

13.) When do we experience our summers? a.) At Aphelion b.) At Perihelion

14.) When do we experience our winters? a.) At Aphelion b.) At Perihelion

15.) We experience summers at aphelion because…? a.) Our hemisphere is tilted away from the sun and not getting direct sunlight. b.) Our hemisphere is tilted toward the sun and getting more direct sunlight.

16.) We experience winters at perihelion because…? a.) Our hemisphere is tilted away from the sun and not getting direct sunlight. b.) Our hemisphere is tilted toward the sun and getting more direct sunlight.

17.) What do we call the time it takes the Earth to complete an orbit around the sun? a.) A Decade b.) A Year c.) A Century d.) A Season

18.) How many months are in a year? a.) Four b.) Sixty c.) Twelve d.) Fifty-two

19.) How seasons are there in a year? a.) Four b.) Sixty c.) Twelve d.) Fifty-two

20.) What are the names of the four seasons? a.) _____________________c.) ______________________ b.) _____________________d.) ______________________

21.) How many days are there in a year? a.) Three Hundred and sixty-five b.) Sixty c.) Twelve d.) Fifty-two

22.) How many weeks are there in a year? a.) Four b.) Sixty c.) Twelve d.) Fifty-two

23.) How many days are there in a week? a.) Four c.) Twelve b.) Sixtyd.) Seven

24.) How many hours are in a day? a.) Four c.) Twenty-four b.) Sixtyd.) Seven

25.) How many minutes are in an hour? a.) Four c.) Twenty-four b.) Sixtyd.) Seven

26.) How many seconds are there in a minute? a.) Four c.) Twenty-four b.) Sixtyd.) Seven