THE SUN,The EARTH, THE MOON (and other space things!)

4th Grade Science Duncan Elementary

THE SOLAR SYSTEMThe Sun is at the center of our Solar System, and 8 planets revolve

around the Sun in a circular or elliptical orbit. Our Earth is the third planet from the Sun, and the only planet in the Solar System with

plants, animals, and people!

Mercury

Venus

Earth

Mars

JupiterSaturn

NeptuneUranus

THE SOLAR SYSTEM AND THE MILKY WAYOur Solar System is a very small part of a VERY LARGE collection of stars, planets,

and space, called the MILKY WAY GALAXY.The Milky Way Galaxy is a very small part of the UNIVERSE, whose size cannot be

determined with certainty.

MILKY WAY GALAXY

THE UNIVERSE

LIVING THINGS ON SOLAR SYSTEM PLANETS?Because they are so close to the Sun, planets Mercury and Venus are too hot for

plants, animals and people to live there. Because they are so far from the Sun, Jupiter, Saturn, Neptune and Uranus are too

cold for most living things. Mars is colder than Earth, and various studies have been conducted to determine whether there are any living things on “the Red Planet”.

Mercury

Venus

Earth

Mars

JupiterSaturn

NeptuneUranus

THE STARS IN THE SKYOn a cloudless night, away from city lights (or using a telescope), you would be able to see millions of stars in the sky. Some stars are brighter and closer than

others. These stars are so far away that the light from these stars took hundreds or thousands of years to reach the Earth.

Some bright stars form a pattern called a CONSTELLATION that looks like a person, animal or thing. The most common one we see in our sky is the “BIG

DIPPER” that looks like a large spoon or soup ladle.

OTHER INTERESTING THINGS IN THE SKY

• At night, we can get a great view of the MOON, in one if its many phases (more about that later!)

• Sometimes, we can see a METEOR flash through the sky and burn up as it approaches the Earth.

• Earth is sometimes visited by one of several COMETS that make their way around the Sun.

• At times, we may see a bright object that is a PLANET with sunlight reflecting off its surface.

• …but you would need to look really hard to see an astronaut cat outside the orbiting International Space Station!

FACTS ABOUT OUR SUN

THE SUNThe Sun is actually a large star. Because the Sun is

closer to us than any other star, it appears as a ball of orange, yellow, or white light in the sky.

The Sun’s bright light prevents us from seeing any other stars in the sky, and is so bright, we would hurt our

eyes if we looked at it directly.

Like most stars, the Sun is a large mass of hydrogen and helium gases that constantly

“burn” and re-generate, giving off heat energy and light. The Sun’s energy keeps us warm. Its light helps us see things around us, and helps

our plants to grow.

• The Sun is 860,000 miles wide, so about 109 Earths could fit inside the Sun!• The Sun is about 93 Million Miles away from Earth.• The Sun does not have any air or water, and is too hot for anything to live there.• The Sun’s light takes 8 minutes to travel to Earth, at the speed of light which is

182,200 miles per second! (fortunately, its light is sent out constantly so we don’t notice any delay)

• The Sun’s surface is rough, with flares, spikes, waves and storms happening all the time, and cooler areas known as sunspots appearing periodically.

MORE FACTS ABOUT THE SUN

About 93 Million MilesAbout 860,000

Miles Wide!(about 35 times wider

than Earth)

REVIEW QUESTIONS!Please answer these questions which are based on the information we have

covered about the SUN!1. Other than the Sun, what are other things we can see in the night sky?2. About how far is the Sun away from the Earth?3. How long does it take the Earth to go around the Sun?4. How much bigger is the Sun compared to the Earth?5. What is the name of the closest star to Earth?6. The Sun is part of a constellation. True or False ?7. We would hurt our eyes if we looked directly at the Sun. True or False ?8. The Sun’s surface is very smooth and consistent. True or False ?9. All of our Solar System’s planets revolve around the Sun. True or False ?10.Our Sun is the largest thing in the Universe. True or False ?11.We could live on the Sun, but would need lots of ice to keep our ice cream

from melting. True or False ?12.Explain why the Sun is so important to us on Earth.13.What are the names of the other planets in our Solar System? Which

planet is closest to the Sun, and which planet is furthest?14.Why can we have a warm day, without ever seeing the Sun shining?

NOW, LET’S TALK ABOUT THE EARTH!

SOME FACTS ABOUT EARTH• The Earth is shaped like a ball that is a little flat on the top and

bottom (at the North and South Poles)• The Earth was formed millions of years ago as very hot rock,

metals and gases.• The planet we call Earth has three parts:

o The CRUST: Rains cooled the Earth’s hot exterior, and made it suitable for life.

o The MANTLE: A middle layer of very hot rock -- when a volcano erupts, we see what the mantle is like

o The CORE: The extremely hot molten center of the Earth• The Earth has an atmosphere that includes:

o Air for us to breathe (though there is less air the further you go away from the Earth’s surface)

o Winds that move warm and cold air across the surfaceo Clouds that hold moisture above the surface, and deposit

rain on the surfaceo Ozone that protects us from the radiation energy given off

by the Sun.

MORE FACTS ABOUT EARTH• Above the Earth’s atmosphere and out into space, there is

ZERO gravity ; that is, there is no force to hold things down or prevent them from floating -- the Earth has gravity that keeps people and objects on the ground.

• The Earth is about 7,900 miles in diameter , and

about 25,000 miles around (in circumference) at the Equator .

• Millions of years ago, the Earth was covered in ice, which eventually melted to form oceans, lakes and rivers.

• Many geologists believe that all the land we see on the Earth today, at one time had been attached – but the land broke apart and drifted to their current locations.

• The highest point on the Earth’s surface is Mount Everest, and the lowest points lie deep below our oceans.

We live on the EARTH, in Michigan, which is here

North Pole

South Pole

This is the EQUATOR, which is an imaginary line at the middle of the

EARTH. The equator is rather summer-like (WARM or HOT) all

year-round.The NORTH POLE is at the “topmost” part of the EARTH, and the SOUTH POLE is at the bottom-most part. Both these

places are winter-like (very COLD) all year-round.

COLD

COLD

WARM to HOT

EARTH CLIMATE

FACTS

Michigan is closer to the cold NORTH POLE than it is to the warm EQUATOR, so our temperatures tend to be much

cooler than countries near the Equator.

North Pole

South Pole

COLD

COLD

WARM to HOT

EARTH CLIMATE

FACTS

Michigan can have cool days in the Summer and warm days in the Winter, because of the winds on the Earth’s surface that

may blow warm Equator air or cool North Pole air towards us.

North Pole

WARM to HOT

COLD WIND FROM THE NORTH

WARM WIND FROM THE SOUTH

EARTH CLIMATE

FACTS

The Earth spins about an imaginary line called an AXIS that extends from the North Pole to the South Pole. The

Earth spins one complete rotation (completely around)

every 24 hours – which is ONCE EACH DAY.

The Earth spins at a rate of about 1,000 miles per hour! …

but like flying in an airplane, when everything moves at the same fast speed it seems like

nothing is moving!!

North Pole

South Pole

THE EARTH’S ROTATION

AXIS

THE EARTH’S TILT: As you may have noticed in previous slides that the Earth is tilted relative to the path it takes around the

Sun. The line from the North Pole to the South Pole is tilted at a small (but important) 23 degree angle.

North Pole

South Pole

NOT LIKE THIS

23o

23o

Orbit Path around the Sun

THE EARTH’S ROTATION

The Sun does not really move, so the Earth’s spin about its axis is what

causes Day and Night to occur. The Sun rises in the Eastern sky and sets

in the Western sky. Sunrise in the East (over the Atlantic Ocean)

DAY AND NIGHT ON EARTH

The Earth travels in an orbit around the Sun. When drawn, the orbit path looks like an ellipse, and this is one REVOLUTION around the Sun. It takes

365 days and about 6 hours for the Earth to make one complete revolution around the Sun.

This means that the Earth is moving around the Sun at a speed of about 66,600 miles per hour!

THE EARTH’S REVOLUTION AROUND THE SUN

About 93 Million Miles

Since it takes 365 days and a few extra hours for the Earth to make one complete revolution around the Sun, we must account for these extra hours on our calendars… This is the reason for adding an extra day to our calendar every 4 years, called a “Leap Year”. Since February is a short month, we add 1 extra day (Feb 29th) to our calendars in February of a Leap Year (2012, 2016, etc. are

Leap Years)

THE EARTH’S REVOLUTION AND “LEAP YEAR”

About 93 Million Miles

The Earth’s orbit around the Sun and the tilt of our Earth are the reasons we: (1) experience four seasons in Michigan – Winter, Spring, Summer and

Autumn (Fall), (2) why our temperatures change during these seasons, and (3) why we have a greater amount of daylight in the Summer than we have in

Winter. WE WILL EXPLORE THIS IN THE NEXT FEW SLIDES!!!

SEASONS and AMOUNT OF DAYLIGHT

In this position, it is WINTER in Michigan and the rest of the United States, with the SUN’s rays coming to us at an angle and not warming us as much

as the direct sunlight that the Equator, and the countries below the equator are getting. Note that in Australia, while we are experiencing Winter, they

are having a nice warm Summer!

THE WINTER POSITION OF EARTH

During Winter, we see the Sun in the southern part of the sky, because Michigan is tilted away from the Sun at this time of year.

In this “Winter” position within our orbit around the Sun, the amount of daylight is at a minimum -- it gets dark at around 5pm.

Note that many people say “the days are getting shorter” in Winter, but every day is still 24 hours long! – what they mean to say is that the daylight amount is getting shorter!

THE WINTER POSITION OF EARTH

WINTER POSITION OF THE SUN IN OUR SKYIn the Winter position of our Earth’s orbit around the Sun, the

Earth’s tilt causes North America (including Michigan) to be tilted away from direct sunlight, so the Sun appears in the southern sky

(closer to the southern “horizon”).

Duncan Elementary School(A Blue Ribbon School!)

Northern Sky

Southern Sky

In this Spring orbit position, the Earth’s tilt is starting to give Michigan more direct sunlight, so we are starting to warm up!

Spring is in the air and the amount of daylight is increasing by a few minutes each day!

THE SPRING POSITION OF EARTH

It’s SUMMER in the United States and North America! The Sun at the center of our solar system starts to appear directly overhead (straight up in the sky) at noon time.

The people south of the Equator, such as in Australia and the South Pole, experience Winter at this time, when the Sun appears in their Northern sky. The Sun’s rays are

approaching those southern areas at an angle so these areas are not as warm.

THE SUMMER POSITION OF EARTH

SUMMER POSITION OF THE SUN IN OUR SKYIn the Summer position of our Earth’s orbit around the Sun, the

Earth’s tilt causes North America (including Michigan) to be tilted into direct sunlight, so the Sun appears directly overhead.

Duncan Elementary School(A Blue Ribbon School!)

Northern Sky Southern Sky

Here, it’s not only SUMMER for us in Michigan, but the day with the longest period of daylight, which is usually June 21st.

South of the Equator, they experience the shortest amount of daylight!

THE SUMMER POSITION OF EARTH

The Earth is still rotating at the same 23 degree axis angle, but as its REVOLUTION around the Sun places it in this AUTUMN position, the amount of sunlight each day

is slowly shrinking, and AUTUMN is coming!

THE AUTUMN POSITION OF EARTH

In this position, AUTUMN is here in Michigan, and the temperature is starting to get “chilly”.

South of the Equator, however, is experiencing springtime, as their temperatures are starting to increase and sunlight each day is getting longer.

THE AUTUMN POSITION OF EARTH

SUMMARY: THE EARTH AND THE SEASONS

In this picture, you see one full year, with a full revolution around the Sun. The Earth keeps the same tilt throughout, therefore causing the Sun’s energy to come to us more “directly” in Spring, more “straight-on” in the Summer, and at steeper

angles in the Autumn and Winter.

SUMMARY: THE EARTH AND THE SEASONS

This is an animation of the seasons occurring over one calendar year…

REVIEW QUESTIONS!Please answer these questions which are based on the information we have

covered about the SUN!

1. Define “Rotation”, “Revolution”, “Axis”, and “Orbit”.2. What is the Equator, and is it hot or cold there?3. Where are the coldest places on Earth, (why are they so cold)?4. How long does it take Earth to make one full rotation?5. How long does it take Earth to make one full revolution around the Sun?6. Explain why we have a Leap Year every 4 years?7. What is the angle that the Earth’s axis is tilted?8. What is the main reason why Michigan does not get as warm in the

Winter (i.e., why the Sun is in the Southern sky)9. What season do we get the MOST sunlight in a given day, and which

season do we get the LEAST sunlight?10.The Sun rises in the __________ and sets in the __________ .11.The Sun moves across our sky because Earth is rotating. True or False?12.Name several of the things in Earth’s atmosphere.13.Why it is possible to have a warm day in Winter or a cool day in Summer?

THE EARTH AND ITS MOONMany planets in our Solar System have more than one moon. The Earth has just one Moon. Our Moon is a sphere of rock formed millions of years ago that acts

as a “satellite” orbiting the Earth as the Earth itself orbits around the Sun.Our Moon takes about 28 days (4 weeks) to travel around the Earth, but since the Earth makes a full rotation once each day, the Moon appears to move across our sky slowly during each night. The Moon is about 250,000 miles away from Earth.

THE MOON’S PHASESSometimes we see the Moon as a full round object in the sky (A “Full Moon”).

However, at most times the Moon’s location relative to the Earth and Sun means that we see a only a portion of the Moon lighted and a portion (or all) of the

Moon “not lighted” (covered in shadows). These different appearances are called PHASES OF THE MOON, as you can see here over a month span (May-June 2005):

THE MOON’S ORBIT AND ITS PHASESThe Moon’s phases have been given names – for example, “Full Moon” when the entire face of the Moon is illuminated for us to see on Earth, and “New Moon” when the back half of the Moon is illuminated and we can barely see the face of the Moon at all.

First QuarterMoon

Last Quarter Moon

Full MoonNew Moon

A FEW MORE OF THE MOON’S PHASES

Astronomers and scientists have given names to a few other Moon phases, as shown here (Waxing and Waning Crescent and Gibbous Moon Phases):

Waxing Crescent (or just

“Crescent”) Moon

Waning Crescent (or just

“Crescent”) Moon

Waxing Gibbous (or just

“Gibbous”) Moon

Waning Gibbous (or just

“Gibbous”) Moon

SUMMARY: THE MOON’S PHASES

This picture shows the positions of the Sun, Earth and Moon, and the different Moon Phases in these positions.

SUN

EXPLORATION OF THE MOON• Neil Armstrong and Edwin “Buzz” Aldrin of the

Apollo 11 mission were the 1st and 2nd persons to walk on the Moon, on July 20, 1969.

• The Moon has no atmosphere, nor oxygen and no plant life, so the astronauts needed special suits with air tanks.

• The Moon’s surface has many large bowl-shaped pits called “craters”, probably from meteor hits.

• The Moon’s has a much lower amount of gravity so our astronauts could jump long distances, and felt much lighter than on Earth. In fact, on the Moon they weighed 1/6 of their weight on earth (their Earth weight divided by 6).

Q: If you weigh 60 pounds on Earth, how much would you weigh on the Moon?

Total Eclipse of the Sun (“Solar Eclipse”) with extremely bright light showing around the Moon

(DAMAGING TO THE HUMAN EYE!)

SOLAR ECLIPSESBecause of the way the Moon orbits around the

Earth, the Moon sometimes moves into a position where it entirely (or partially) covers the

Sun in the sky. This is called a “TOTAL” or “PARTIAL” Eclipse.

Note that partial solar eclipses occur somewhere on Earth every 18

months or so. Total eclipses at any given location on Earth are rare – they only occur in Michigan every

410 years or so!

LUNAR ECLIPSESOccasionally, the Earth casts its shadow on the Moon during the day, thus causing the Moon to go from visible to shaded then back to visible again.

REVIEW QUESTIONS!Please answer these questions which are based on the information we have

covered about the MOON!

1. The first person to walk on the Moon was Neil _______________.2. The Moon is invisible (darkened completely) during the _________ phase.3. _______________ are bowl shaped pits found on the Moon’s surface.4. The Moon is Earth’s natural ______________ because it orbits the Earth. 5. A person who weighs 120 pounds on Earth will weigh only _____________

pounds on the Moon.6. When the Moon blocks our view of the Sun, it is called an ____________.7. The Moon shines because of reflected light from the _____________.8. When the Moon appears as a sliver of white, we call it a ____________

Moon.ADDITIONAL LUNAR QUESTIONS: Who was the 2nd person to walk on the

Moon? What was the name of the mission that sent the first astronauts to walk on the Moon’s surface, and what year did this mission take place? How many days does it take to see all the Moon’s phases? Also, draw a few of the Moon’s phases.

REVIEW QUESTION ANSWERS!

1. The first person to walk on the Moon was Neil Armstrong .2. The Moon is invisible (darkened completely) during the New Moon phase.3. Craters are bowl shaped pits found on the Moon’s surface.4. The Moon is Earth’s natural satellite because it orbits the Earth. 5. A person who weighs 120 pounds on Earth will weigh only 120/6 = 20

pounds on the Moon.6. When the Moon blocks our view of the Sun, it is called an eclipse.7. The Moon shines because of reflected light from the Sun.8. When the Moon appears as a sliver of white, we call it a Crescent Moon.

ADDITIONAL LUNAR QUESTIONS: Who was the 2nd person to walk on the Moon? (Buzz Aldrin) What was the name of the mission that sent the first astronauts to walk on the Moon’s surface, and what year did this mission take place? (Apollo 11, in 1969) How long does it take to see all the Moon’s phases? (about 28 days)

MORE REVIEW QUESTIONS!Please answer the questions presented here, which relate to the SUN, EARTH

and MOON. Circle S for Sun, E for Earth and M for Moon (all that apply)!

1. Is basically round: S E M

2. Not suitable for human life: S E M

3. Rotates fully around once each day: S E M

4. Have different shapes called phases: S E M

5. Has an atmosphere and plant life: S E M

6. Has a mantle and a core: S E M

7. Is mainly made of the elements Hydrogen and Helium: S E M

8. Is the largest item in our Solar System: S E M

REVIEW QUESTION ANSWERS!

1. Is basically round: S E M

2. Not suitable for human life: S E M

3. Rotates fully around once each day: S E M

4. Have different shapes called phases: S E M

5. Has an atmosphere and plant life: S E M

6. Has a mantle and a core: S E M

7. Is mainly made of the elements Hydrogen and Helium: S E M

8. Is the largest item in our Solar System: S E M

SUN, EARTH, MOON CROSSWORD!

SUN, EARTH, MOON CROSSWORD CLUES

ACROSS1. Mars color4. Phase showing most of the Moon’s surface6. Planet between Venus and Mars8. Collection of stars that looks like a thing11. When we add a day to February12. Earth’s nearest star13. Aldrin or Toy Story’s Lightyear17. When the Moon blocks out the Sun18. This circles Earth every 28 days20. Lunar holes caused by meteor strikes24. The Moon is a natural _______ of Earth27. Planet between Earth and Saturn28. Earth spins about this imaginary line

extending from pole to pole32. Apollo 11 moonwalker33. One of earth’s poles34. What keeps things from floating off –

Moon has less of this than Earth!36. Darkened Moon phase

DOWN1. Saturn has many of these around its surface2. Star pattern, the “Big ________”3. Earth takes about 365 days for one or these5. Planet near Neptune7. Earth makes one full _______ each day8. “Sliver” Moon phase9. Circling around Earth or around the Sun10. Protective layer in the Earth’s atmosphere14. When the Earth casts a shadow on the Moon15. NASA mission to the Moon16. Planet too hot for living things19. A planet between the Sun and Mars21. Apollo 11 moonwalker22. Planet near Jupiter, and former car brand23. Lies below Earth’s crust (and above fireplace)25. Lands on this imaginary line receive more direct

sunlight than anywhere else26. Earth has 23 degrees of this29. The Sun rises here30. Volcano output, evidence of Earth’s hot inner core31. Needed to breathe, the Moon has none

SUN, EARTH, MOON CROSSWORD!

SUN, EARTH, MOON CROSSWORD SOLUTION

Thank youfor being a GREATDuncan Explorer!

4th Grade Science Duncan Elementary