Detrital rocks are formed from rock particles. ranging in size from boulders to microscopic clay particles. Chemical, or inorganic rocks, are made from particles that can dissolve in water.  Finally, the organic sedimentary rocks are formed from plant remains.  To the right, is an image of sandstone, a detrital sedimentary rock.


Igneous Rocks:  
These rocks form most of the Earth’s crust. There are more than 600 different kinds all formed from cooled magma.  Magma near the surface cools quickly producing rocks with small mineral deposits, or extrusive igneous rocks.  Intrusive igneous rocks are formed when magma takes longer to cool.  Larger mineral deposits are formed due to the extra cooling time.  Basalt and Granite, shown below, illustrate the two different types.

        
   Basalt- an extrusive, igneous rock              Granite- intrusive, igneous rock

Metamorphic Rocks:
This type of rock typically forms when sedimentary, igneous or other metamorphic rocks are exposed to extreme heat and/or pressure.  These extreme factors actually change the chemical composition of the original rock by realigning the crystals within the rock.  Here are some common types of metamorphic rocks:

 
         Quartzite                         Slate                             Phyllite                            Schist


Mohs Scale of Hardness:

 

Additional Resources:

• FOSSWeb: Castle of Doom
• The Mystery of the Golden Cube
• The Virtual Rock Box
• Interactive Rock Cycle
• Glencoe: Rock Virtual Lab

Evidence to Support Pangaea: 

• The mountain ranges of Eastern North America and Western Europe match in terms of similar composition, age and rock.
• The east coast of South America and the west coast of Africa contain Cynognathus fossils.  These land-dwelling animals had small brains and did not have flippers or gills.  The only way they could have travelled would be across land.  At some point, they would have had to live on the same land mass.
• Similarly, the Indian peninsula, the east African coast, and Australia all contain Lystrosaurus and Glossopteris fossils.

Collection of Resources

• Shake, Rattle and Slide
• Pangaea Project
• Extreme Science
• How Stuff Works: Pangaea Video
• Continental Divide Puzzle
• Major Plates of the World Quiz 
• Pangaea Interactive Map Game
• Pangaea, the Comeback
• Windows to the Universe: Sea Floor Spreading
• Slip, Slide, Collide
• Mountain Maker, Earth Shaker

Lesson: The Earth's Interior

Grade Level: K-3

Background Information:  

The earth is comprised of four basic layers: the crust, the mantle, the outer core and the inner core.  The crust is the outer most layer.  This is the layer upon which we live and is made of soil, rock and seabed.  Of the four, this is the thinnest ranging from a thickness of 8km beneath the oceans to 40km beneath the continents. Moving deeper, we have the mantle.  The mantle is a semi-solid layer of rock that flows due to pressure creating slow-moving currents.  This layer is around 2900km thick.  Deeper still, we have the outer and inner core both of which are made mostly of iron.  The outer core is the only liquid layer and is around 2300km in thickness.  The temperature here lies between 4000-5000 degrees Celsius.  It is thought this layer plays a significant role in the earth's magnetic field.  Finally, the inner core is a solid ball of iron with a diameter of 24km.  Although the temperature here is between 5000-7000 degrees Celsius, the inner core remains solid due to the high pressure.

Man has never travelled to the center of the earth and likely never will.  The models we have of the earth's interior are based upon information gathered during earthquakes and other seismic events.  Scientists study the behavior of seismic waves, like p-waves and s-waves, to increase their knowledge and improve their models.  

Vocabulary:

crust, mantle, outer core, inner core, interior,  seismic, p-wave, s-wave

Activity Suggestions:

1. Watch the BrainPOP movie, Earth's Structure, to jump start the unit.
2. Watch the Savage Earth animation.
3. Use Visuwords to explore the meaning of the vocabulary words.
4. Create a wordle highlighting the key facts from this unit.
5. Make an Earth pizza to review the interior structure. Yummy!

Here are the directions for the pizza.

Step 1: Make your own pizza dough or purchase a ready-made crust.

Step 2: Spread pizza sauce over the entire surface.

Step 3: Cover the sauce with a thick layer of mozzarella cheese.  Cover the pizza right up to the edge because this layer will show beyond the other layers.  This represents the mantle.

Step 4: Spread a thin, circular layer of cheddar cheese in the center of the pizza.  This circle should be about twice the diameter of the tomato slice.  It will represent the outer core.

Step 5: Add a slice of tomato in the center of the cheddar cheese layer.  This will serve as the solid, inner core.

Here's a picture of our earth pizza before baking.

We baked our pizza at 425 for 8-10 minutes.  Then, took another picture before digging into the earth!

I give credit to the writers at Pandia Press for coming up with a great, edible science activity!  Our kids loved the lab and were eager to share their knowledge about each layer of the earth's interior.  As usual, I was blown away with what they were able to take in and process.  Next week, we are exploring earthquakes and volcanoes.  They are so excited and looking forward to making things quake and explode.  Should be another week of learning fun!

• Scholastic's Study Jams: The Water Cycle
• USGS Water Cycle Resources
• BBC: The Water Cycle
• MSNucleus: Water Cycle
• Water Cycle Interactive
• Water Cycle Bag Activity
• Teaching the Water Cycle -- Great Lesson!!
• KidZone: The Water Cycle
• Droplet and the Water Cycle Game
• EPA: The Water Cycle Interactive
• NeoK-12: Water Cycle Videos and Games

Materials:

• lab handout 
• clear, plastic cups and foam cups
• table salt
• red food coloring
• table salt
• hot and cold water
  

Creating an Underwater Waterfall

1. Fill a plastic cup nearly full with cool water.

2. Fill a foam cup half-full with hot water.  Add a pinch of salt.  Add 6 drops of red food coloring.  Stir until the salt dissolves.

3. Place the eyedropper into the hot red water to warm it up.  After a minute, fill the dropper with the water.

4. Hold the dropper so that it lies at a flat angle at the surface of the clear water with the tip just below the surface.  Gently squeeze out a layer of hot red water onto the surface of the clear water.

5. After a short cooling time, the red layer will form little waterfalls that sink through the clear water.

Conclusions:
1. Explain why the red water floats at first.

(The hot, red water floats because it is less dense than the cold water.)

2. Explain why the red water eventually sinks. 

(The red water eventually sinks because heat flows out of the hot water to the cold water until the temperatures are the same.  Then, the higher concentration of salt in the red water becomes the controlling factor.  The high slainity of the red water makes it more dense than the cold water.  As a result, it sinks.)

This activity was based upon material outlined in CPO Earth Science.

Density can be defined as the ratio of an object's mass per unit volume.  In other words. D=m/v!  More speficially, density depends upon two things:

1. The mass of each molecule that makes up the material.
2. The amount of space or volume the material takes up.

For example, a real boulder has a greater density than a styrofoam boulder. Why? The individual styrofoam molecules have a lower mass and are not "packed" tightly together.  Whereas, the individual molecules that compose a rock are higher in density and "packed" more closely together.  As a result, the real boulder has a greater density than a styrofoam boulder.

Another fact to consider is the density of a material remains the same under the same conditions.  For example, the density of aluminum is 2.7 g/cm^3.  Whether you are talking about aluminum foil or aluminum wire, the density remains the same provided the sample is not hollow or contains a mixture of materials.

What if we have an irregular-shaped object? It is not as straightforward to determine the density because it is more difficult to calculate the volume.  There is a way, though!  The volume of odd-shaped objects can be found by using a graduated cylinder and the fact that 1ml = 1cm^3.  Here's an example.

Let's say we want to find the volume of a rock you found while hiking.  Fill a graduated cylinder with water to a set amount, say 50ml.  Then, add your rock.  Be careful not to splash any of the water out!  Now, note the new water level.  Let's say it rose to 61ml.  Then, the volume of the rock could be found by the following method:

Volume of Rock: 61ml - 50ml = 11ml or 11 cm^3

Pretty easy, right?  Let's face it, most objects in nature are irregular inshape.  This provides an easy way for determining volume and, ultimately, calculating density.

Deeper Explorations:

Activity 1: Floating Carrots

Begin by asking your students if they thing a carrot will sink or float if placed into a container of tap water.  tally your responses.  Have someone drop the carrot into the container and observe what happens.  It should sink because the density of the carrot is greater than the density of the tap water.  Now, ask your students what they think would happen if you added salt to the water.  Again, tally your responses.  Begin adding salt in measured amounts.  Eventually, the carrot should float.  Make note of how much salt you added.  At this point, the carrot floats because the density of the salt water is greater than the density of the carrot.  It is very easy at this point to displace enough water to create a buoyant force that flaots the carrrot.

Activity 2:  The Dead Sea- Sink or Float

Visit the Dead Sea (at least virtually) using Google Earth.  Go online and explore this amazing place.  Find out answers to the following:

• How was the Dead Sea formed?
• Why it is easier for people to float here?
• Is it really deadly?

Extreme science is a great place to begin!

Obviously, this just scratches the surface when thinking about the varied ways we encounter measurements in our daily lives.  Hopefully, this will stimulate curiosity about the topic and spark a discussion.  Do we use liters or gallons?  Do we use kilometers or meters?  Metric or standard? Go ahead and try it!

Highlight: Astrophysicist (Luc- 3rd grade)

Astrophysicists are scientists that study the physics of the universe.  They have strong math and physics skills.  Stephen Hawking is a famous cosmologist and astrophysicist who has creative and brilliant ideas about time travel and black holes.  Astrophysicists are galactic cool and rock the universe!

Cool Sites to Visit:

• Astrophysics for a Ten-Year-Old-Mind
• GSFC Astrophysics Science Division
• GSFC StarChild
• Kids Net Astronomy and Astrophysics
• George’s Secret Key to the Universe
• Kids Astronomy
• NASA Kids

Highlight: Volcanologist (Ellie- 2nd grade)
Volcanologists are scientists who study volcanoes, lava and magma.  They visit active volcanoes to collect rock and lava samples.  They also make predictions about when volcanoes may erupt.  We think people have been studying volcanoes since 7000 B.C.  Wow!

Cool Sites to Visit:

• How to Become a Volcanologist?
• Discovery Kids: Volcano Explorer
• Weather Wiz Kids: Volcanoes
• National Geographic Kids: Volcanoes
• Facts About Volcanoes
• neoK12: Volcanoes
• National Geographic: Forces of Nature- Volcanoes

Highlight: Marine Biologist (Abby-5th grade)
Marine Biology is the study of organisms in the ocean.  These scientists study a wide variety of life ranging from the prodigious blue whale to microscopic plankton.  I find the cetaceans the most interesting.  This group of marine mammals  includes  the many species of toothed and baleen whales.  From the blue whale measuring over 30m to the Hector’s dolphin measuring only 1.25m, marine biologists agree these are amazing, social animals to observe!  

Cool Sites to Visit:

• The Marine Mammal Center
• National Geographic: Blue Whale Interactive
• NOAA Online Games and Activities
  • Spotlight: Whale Migration Game
  • The Kid's Times

• ReefEd- Great Barrier Reef Resources
• National Geographic Kids Creature Feature
• Winter's Tail
• Explore the Marine Sanctuaries
• Jonathan Bird's Blue World TV
• Kids Do Ecology: Marine Mammals



Activity

• As a class, view the introduction to surface behaviors online at Maui Whale Watching Tours.
• Discuss what behviors students think are the most common.
• Pass out the tally sheets to each student.
• View the video together and have class tally surface behaviors. 

• Upon completion, graph results online at Create-a-Graph sponsored by NCES Kids.

Marine mammals

For these mammals, body temperature must remain between 95-100.4 degrees Fahrenheit (35-38 degrees Celsius).  Blubber is a thick layer of fat cells beneath the surface of the skin that preserves heat and keeps body temperatures in the ideal range.  It's the perfect insulator!  This layer of fat is very thick!  For example, a dolphin has a layer of blubber around .7” and the fat layer for sperm whales is between 1-2ft thick.  In addition to serving as an insulator, blubber is also used to store fat, as an energy source and for buoyancy. 

Scientists have recently discovered a downside to this layer of insulation.  Blubber also stores and/or absorbs harmful chemicals and toxins that are polluting the earth's waters.  These toxic chemicals are feared to be passed from parents to offspring.  Whale blubber is documented to have higher levels of mercury, PCB’s and pesticides! 

Activity

Materials: white model magic, buckets, and ice water

Procedure:

• Brainstorm ways humans stay warm.  Now, lead a discussion about how they think marine mammals survive in their ocean habitats. 
• Discuss with students what they think will happen if they plunge their finger into a bucket of ice water.  Record results.
• If you have a brave student, you can let them test the frigid water before continuing on with the activity.
• Now discuss with students what they think will happen if a finger covered in"blubber" is plunged into a bucket of ice water.  Record your results.
• Distribute balls of model magic to each student.  Ask them to flatten each ball using the heel of their hand.  Now, have them wrap their index finger completely.
• Once covered, students will take turns plunging their "blubber finger" into the icy water.  
• Ask students to form an opinion about how blubber works and add to a class wallwisher.  Each student should form a response.

Conclusions: All marine mammmals, like other mammals, are warm-blooded.  Their body temperature remains constant and does not adjust to changes in the surrounding temperature.  Blubber provides the perfect layer of insulation to keep them warm.  It's their built in "snuggy"!

To make this super fun, you could record the demonstratin with a Flip camera and post on a class wiki or create a slideshow using Google Docs.  In addition, you could easily post student responses there.  Be creative have fun learning!