Mapping the Solar System

I recently encountered this activity for the first time, on the McDonald Observatory website.  I've since found the same activity on numerous other sites.  I don't know where it came from first, but I'll give credit to the place where I first saw it.

Anyway... it's a super simple way for students to map the solar system and get a feel for how much distance is between the planets.  In short, it's brilliant!

Each student will need a sentence strip or a length of adding machine/calculator paper.

Hold the paper vertically and label (in small letters) one end of the strip "Sun" and the other end "Pluto".

At this point, you can have students fill in the planets with their best guesses as to their placement.  Or you can just make the accurate map.  It's up to you and your situation.

To make the map:
Fold Pluto to the Sun.  Label Uranus on the crease.
Fold Pluto to Uranus.  Label Neptune on the crease.

 Fold the Sun to Uranus.  Label Saturn on the crease.
Fold the Sun to Saturn.  Label Jupiter on the crease.
Fold the Sun to Jupiter.  You can label the crease Asteroid Belt or leave this space blank.

Fold the Sun to the Asteroid Belt.  Label Mars on the crease.
Fold the Sun to Mars. Label Venus on the crease.

Label the space between the Sun and Venus, Mercury.  (You could fold the Sun to Venus and label the crease, but the space gets a little tight to make more folds at this point).

Label the space between Venus and Mars, Earth.

That's it!  You've completed your map!  And it's incredibly accurate for such a simple model.

I'm thinking it might be fun to convert distances to some other notable bodies in the cosmos to this scale and lay out the sentence strips to show kids the vast amount of space in space.  I'll let you know what I come up with!

Solar System: Pictorial Comparison

Originally posted on February 2, 2010

I LOVE these pictures. I first learned of them a few years ago and promptly printed and laminated a set for my classroom. I was reminded of them recently when I received them as an email attachment.

I think the art is beautiful and I can just stare at them-my mind spinning, trying to comprehend the size of the universe, all the while.

I don't know the source for these pictures. If someone out there does, please let me know and I will gladly add it.

Solar System: The Planets to Scale: Part II

While planet size is out-of-whack in textbooks, it's nothing compared to the distances between planets.  Most textbook pictures look a little something like my picture above (except, of course, the planets all look much closer in size), the planets are all right next to each other.  The textbooks do it for the same reason that I did: it's the way to make all the planets fit. 

There's so much empty space in space that it's darn near impossible to show students both the planets and their orbits to scale.

But, if you want to give it a shot, pick up your props from last week's solar system and head out for a walk....

Start at the sun and walk 190 feet.  Place the peppercorn (Mercury).

Walk 170 feet.  Place the mini-marshmallow (Venus).

Walk 131 feet.  Place the Gobstopper (Earth).

Walk 263 feet.  Place the split pea (Mars).

Walk 601 yards (about 1/3 mile).  Place the soccer ball (Jupiter).

Walk 1/3 mile.  Place the melon (Saturn).

Walk 1 mile.  Place the baseball (Uranus).

Walk 1 mile. Place the small apple (Neptune).

Walk 1 mile.  Place the sprinkle (Pluto).

You've walked more than 3 1/2 miles from the sun to get to that tiny sprinkle of Pluto.  How much sun do you think Pluto sees?  Not much! 

Given that you probably don't want to walk your students out 3 1/2 miles (and then back 3 1/2 miles), you might want to have them walk the first 190 feet, to get an idea of the distance.  And, then you could determine where each of the other planets would fall, within your school and community.  For example, the Earth is at the cafeteria, or Uranus is at McDonalds. 

It's completely mind-boggling and a lot to think about!

Solar System: The Planets to Scale

Textbooks are notorious for completely out-of-whack drawings of the planets in our solar system.  They're about as out-of-whack as the solar system models made by 3rd graders - you know the ones, made from styrofoam balls.  The craft stores only sell about 3 sizes of styrofoam balls, so Jupiter ends about being about twice as big as Mercury and Pluto. And the sun is maybe a little bigger than Jupiter...

Remember these pictures?  They're a good place to start your discussion of planet size. 

But, why not add some props to make the lesson even more fun and memorable.

For each planet (and the sun) I'll give you the object I used, the planet's actual diameter and the scaled diameter (so you can take your ruler with you to the produce department in search of the perfect melon to represent Saturn). 

The Sun:

1,400,000 km --> 140 cm

1/2 plastic tablecloth

Mercury:

4,900 km --> 0.49 cm

peppercorn

Venus:

12,100 km --> 1.21 cm

mini-marshmallow

(in the pictures, I used a Gobstopper for both Venus and Earth because my marshmallow was missing)

Earth:

12,800 km --> 1.28 cm

Gobstopper

Mars:

6,800 km --> 0.68 cm

split pea

Jupiter:

143,000 km --> 14.3 cm

small (size 3) soccer ball

Saturn:

120,000 km --> 12.0 cm

melon

Uranus:

51,800 km --> 5.18 cm

baseball

Neptune:

49,500 km --> 4.95 cm

small apple

Pluto:

2,300 km --> 0.23 cm

sprinkle

I like to begin the demonstration by showing students the sun and then having them guess how big Earth would be at that scale; everyone holds up their hands to show me how big it would be.  They always think it's way bigger than it is! 

After revealing the Earth, we then go back to Mercury and work our way through all the planets in the same way. 

It's a good way to begin a discussion of Pluto's classification, as Pluto looks absolutely puny after those gas giants. 

Rotate/Revolve Model

Make this simple model to demonstrate the differences between rotation and revolution.

Thread a practice golf ball onto a pipe cleaner.  Twist the pipe cleaner closed, to make a loop. 

To show rotation: spin the ball.

To show revolution: slide the ball around the pipe cleaner.

The materials are so simple and inexpensive, you could make a classroom set of these and have students try it out themselves.  


You can make a larger scale model using a hula hoop and a wiffle ball.  You will have to cut part of the ball open to get it around the hula hoop. 

Sun Says...

This is a great activity to do out on the ball field, if you have the opportunity.  If not, it works perfectly well in the classroom, though you may have to move a few desks around.

The students form a large circle - they are the planets.
You stand in the middle of the circle of the students - you are the sun.

You, as the sun, call out directions to the planets, your students.  There are three different directions, you can all them out in any order you please, as many times as you please.

The directions are:
--"Rotate" - the students spin around in one place
--"Revolve" - the students walk around the sun in their large circle
--"Rotate and Revolve" - the students do both of the above tasks at the same time.

It's a great way to help students learn and understand the difference between rotating and revolving.  It's simple enough for 3rd grade students and fun enough for middle school students (who always love a reason to be out of their seats). 

Earth vs. moon: Diameter Comparison

Draw a 40 cm (diameter) circle on your board.  [You could also cut out a 40 cm circle, but that takes a bit more work - you need to use a piece of poster board or tape several pieces of paper together].

Tell your students that that circle is the Earth (you could get creative and add some continents and oceans to your circle drawing to make it more convincing, if you're so inclined).  They now need to cut out a circle to represent the size of the moon.

Have the students tape their moons on the board around the Earth drawing.  Are the moons about the same size, or was there a lot of variation in the students' guesses?

The correct size for the moon is approximately 10 cm.  Measure the students' moons and remove all but the one closest to accurate (if there are none that are terribly close, you might want to remove them all and replace them with one of your own that's correct).

After comparing the size of  the Earth and moon next to each other, move the moon 1200 cm (12 m) away from the Earth - that's the distance between the two to the same scale.  Quite something, isn't it?

******
Presented by Dr. Christine Anne Royce (Shippensburg University) at the 2007 New Jersey Science Convention.

Moon vs. Earth: Volume Comparison

Here's a hands-on way for your students to learn about the size difference between the Earth and moon.

Each group of students (2-4 works well for this) will need three cans of play-doh (full-size cans).  They can be the same color or different, it doesn't matter, but play-doh from the different cans will get mixed together.


The group begins by dividing the play-doh into 51 lumps/balls; that's 17 from each can.  These do not need to be exactly the same size, and they do not need to be rolled into perfect balls.  You will have some students who want to be very exact about it and it will frustrate them a bit (myself included); try to keep them moving so this doesn't become an all day activity.

After each group has their 51 lumps of play-doh, they will need to decide how to lump them back together so that they have two balls - one representing the Earth and the other the moon.

For example, they could smush 20 lumps together to make the moon and the other 31 together to make the Earth.  Or 11 lumps to make the moon and 40 to make the Earth.

They need to work as a group to come up with some sort of consensus about how to divide their lumps.  Once a consensus has been reached (some discussion will probably need to take place), they can go ahead and smush the play-doh together to create the Earth and moon.

Upon completion of this, time should be taken to go around the room and have each group share their Earth and moon and the number of lumps of play-doh found in each.

Then it's time for the big reveal... Using this model, the moon should be made of 1 lump of play-doh and the Earth made of 50 lumps of play-doh.  The moon is approximately 1/50 of the Earth's volume.

If you wish to continue... the distance between the Earth and the moon is approximately 30 times the Earth's diameter.  So, measure you Earth lump, multiply the number by 30 and move the moon that far away from the Earth.  

Now, if you start thinking about how small the Earth is in comparison to the Sun, you get a feel for how tiny our moon is within the solar system.... but that's a discussion for another day...

******
Presented by Dr. Christine Anne Royce (Shippensburg University) at the 2007 New Jersey Science Convention.

Gravity: Weight on Different Planets

Because of the varying sizes and compostion of the planets, each planet has a different amount of gravitational pull. A stronger gravitational pull means that objects are being pulled toward the center of the planet with greater force. The end result is that the object weighs more.

(remember... weight is the measure of gravitational pull on an object, mass is the amount of "stuff" an object is made up of - that doesn't change)

In short:
The larger, more massive the planet, the more gravitational pull, the more something weighs.

The smaller, less massive the planet, the less gravitational pull, the less something weighs.


To help give students a feel for these differences, I created these:

(I've got a whole set, this is just a representative sample!)

I used this calculator (very cool - have your students play around with it to find their weight on other planets) and an Earth weight of 50 g.

The calculator gave me the following weights:
Mercury: 18.9 g
Venus: 45.3 g
Mars: 18.8 g
Jupiter: 118.2 g
Saturn: 45.8 g
Uranus: 44.4 g
Neptue: 56.2 g
Pluto: 3.3 g

I then created these containers, by taping two cups, filled with an appropriate amount of stuff, together.

It's probably not the best container, but it met these requirements:
1 - Light enough to account for the weight on Pluto when empty.
2 - Opaque - I didn't want students to see through the container. I wanted it to look like they were all the same thing, they just weighed different.
3 - I had them on hand.

I believe I mostly used dried peas/beans for the filling. Jupiter may have a few pennies or other more dense weight thrown in to bulk it up!

If you have a dense material on hand (lead, or something of that sort), you could use film canisters, which would be sturdier than my creation.

Solar System: Pictoral Comparison

I LOVE these pictures. I first learned of them a few years ago and promptly printed and laminated a set for my classroom. I was reminded of them recently when I received them as an email attachment.

I think the art is beautiful and I can just stare at them-my mind spinning, trying to comprehend the size of the universe, all the while.

I don't know the source for these pictures. If someone out there does, please let me know and I will gladly add it.