Thursday, March 31, 2011

Public Service Announcement: Dihydrogen Monoxide

Watch out for this substance... Dihydrogen Monoxide (DHMO)

From the Coalition to Ban Dihydrogen Monoxide....
Dihydrogen monoxide is colorless, odorless, tasteless, and kills uncounted thousands of people every year. Most of these deaths are caused by accidental inhalation of DHMO, but the dangers of dihydrogen monoxide do not end there. Prolonged exposure to its solid form causes severe tissue damage. Symptoms of DHMO ingestion can include excessive sweating and urination, and possibly a bloated feeling, nausea, vomiting and body electrolyte imbalance. For those who have become dependent, DHMO withdrawal means certain death.
You can also visit DHMO.org for more information and ways to get involved.

Public Service Announcement: Dihydrogen Monoxide: UPDATE!

April Fools*!!

Dihydrogen monoxide is another name for water - dihydrogen means 2 hydrogen atoms and monoxide means 1 oxygen atom - H2O!

Share the information from the Coalition to Ban Dihydrogen Monoxide with your students and see if you can get them going - some of them will jump right on board!  (You probably work with some people who would join the crusade as well)

It's another lesson in making sure you think and evaluate as you read and listen - everything stated in the "article" is true, but I don't think anyone really wants to ban water. 

I've also used this activity with students learning about the rules of compound nomenclature and it has the same effect, whether it's April Fool's Day or not.


*Yes, I know April Fool's Day isn't until tomorrow, but if I waited until tomorrow to share this gem, you would have to wait a whole year before sharing with your students and that just didn't seem right.

Wednesday, March 30, 2011

Plants: Grow a Carrot Top

Sometime, when you cut up some fresh carrots, try this activity.

Place the cut off carrot top on a small plate.  Pour some water on the plate.

Leave the plate in a warm, bright spot for a few weeks and observe - a new carrot starts to sprout!

Tuesday, March 29, 2011

Earthquakes: A Letter to the 3 Little Pigs

After learning about earthquakes and earthquake resistant structures, have your students write a letter to the 3 Little Pigs, suggesting ways they could build their houses to be earthquake (or wolf) resistant.

The letter could be written from a friend  -
a personal letter passing along information that might be helpful

Or from a government official -
a letter outlining city or state requirements for earthquake resistant structures

The letters should include at least 5 suggestions. 

Encourage students to get creative in their writing and also in their presentation - written on a piece of stationary or as an email if it's a letter to a friend, written on a piece of "letterhead" if it's from a government official. 

Monday, March 28, 2011

Measurement: The Symmetrical Human Body

Practice measuring length while learning a little more about your body.

The human body is proportioned with almost exact symmetry.  This symmetry allows a ballerina to leap gracefully, an athlete to run fluidly and a child to stop suddenly.  It also gives each of us the balance we need for our organs to function healthfully.

The human body's proportions are often expressed in terms of the length of your head.  Measure the following lengths and see how closely your body fits the mold. (These measurements are for adults, your students might not fit them yet as proportions change as we grow into adulthood).

Record all measurements in cm.

Measure the length of your head. ____ cm

The height of an adult is 8 times the length of the head, or 8 "heads".  Your height is ____ cm, which is ____ heads.

The distance from your hips to your feet is 4 heads.  This distance on you is ____ cm or ____heads.

The length of your head should equal the width of your waist.  Does it?

Your knees are 6 heads from the top of your head.  This length on you is ____ cm or ____ heads.

The width across the shoulders is 2 heads.  Your shoulder width is ____ cm or ____ heads.

The length of your foot equals 1 head.  Your foot length is ____ cm or ____ heads.

The length of your forearm from the inside crease of your elbow to the wrist bone equals 1 head.  This length on you is ____ cm or ____ heads.

Your waist is 3 heads down from the top of your head.  This length on you is ____ cm or ____ heads.

Your hands reach the middle of the thigh, or 5 heads down.  This distance on you is ____ cm or ____ heads.


**See what other proportions you can come up with.  For example:
--Your forearm is the same length as your foot.
--The length of your pinkie is the height of your ear.

Friday, March 25, 2011

A Science Party Fit for a Princess

For my niece's 5th birthday, she thought a science party would be fun (she's very interested in all things science), but only if it could be a princess science party!  That one had us stumped for a bit, but eventually I put together some ideas that seemed to work. 

I thought I'd share them, in case anyone else is in need of some princess science ideas. 

And to prove that you can connect science to anything!

I didn't get any shots while the girls were in action - we were too busy having fun to worry about the camera, but I can give you an idea what we did.

First, we did some Princess Potions

The girls each had a "place mat" like the one shown above.  In the large circle there was a cup that contained some red cabbage juice.  There were smaller cups sitting in spots A, B and C.  Cup A contained some baking soda dissolved in water, Cup B contained vinegar and Cup C contained water. 

Each girl selected one of the smaller cups (A, B or C) and poured it into the large cup.  If the potion turned pink, she earned her tiara.  If the potion turned green, she had to kiss a frog and try again.  If the potion stayed blue/purple she had to try again.


Next up was the Magic Paper:
The girls kept the A, B and C cups from above.  They were each given a piece of "magic" paper - goldenrod paper.  They needed to unlock the paper's magical powers.  They dipped a q-tip into one of the solutions (A, B or C) and then attempted to write on the paper.  Choosing the right solution would result in red marks on the paper and earn the princesses a candy bracelet.

Princess Tea:
This was a race to see who could make a cup of "tea" the fastest - i.e. who could dissolve a sugar cube the fastest.

The girls were each given a menu:

They had to choose whether they wanted hot water or cold water, a whole sugar cube or crushed sugar cube, and whether or not to stir.

After they made their selections, we raced.  Completion of the task earned the girls a new wand.

And finally, to complete the whole princess ensemble, the girls made shirts using the pinwheel chromatography method (i.e. Sharpies and rubbing alcohol).  Lots of fun and creative designs.
 

Thursday, March 24, 2011

Inertia: : A Penny for Your Finger

Hold out the index finger on your non-dominant hand.  Balance an index card on your finger and then place a penny on top of the card (so that the penny is essentially sitting on your finger - there's just an index card between them).

Use your dominant hand to flick the index card out of the way.  If things are balanced properly and you flick the card quickly enough so that inertia overcomes friction, you'll be left with a penny balanced on your finger. 


Wednesday, March 23, 2011

Adaptations: Bird Beaks - Version 3

This is the most advanced of the bird beak labs, as students need to record times, calculate average and graph data.  For simpler bird beak labs, check here and here.

There are 8 stations.  At each station, the student will use each provided beak to collect a prescribed amount of the food source.  Another student will time how long it takes for each beak to accomplish the task.  Several trials will be performed with each beak.  Then the averages will be calculated and a bar graph will be constructed. 

Station 1:
Nectar: water in a graduated cylinder
Tools:
--Shoestring
--Medicine dropper
--Sponge strip
Challenge:
Collect 10 mL of nectar

Station 2:
Worms: gummy worms in sand
Tools:
--A straw
--Chopsticks
--Wrench
Challenge:
Remove all the gummy worms (make sure they're buried after each trial)

Station 3:
Seeds: sunflower seeds
Tools:
--Pliers
--Chopsticks
--Tweezers
Challenge:
Crack the seed shell and remove the seed inside.

Station 4:
Fish: styrofoam squares floating on water
Tools:
--Chopsticks
--Tweezers
--Slotted spoon
Challenge:
Remove all the styrofoam squares from the water

Station 5:
Algae: loose tea in water
Tools:
--Slotted spoon
--Strainer
--Tweezers
Challenge:
Remove all the tea from the water

Station 6:
Flying Bugs: popped popcorn, tossed in the air by another group member
Tools:
--Tongs
--Envelope
--Chopsticks
Challenge:
Capture 20 kernels, while it is in the air.

Station 7:
Insects: rice in a styrofoam log
Tools:
--Medicine dropper
--Tongs
--Tweezers
Challenge:
Remove 30 insects from the log.

Station 8:
 : marshmallows hanging from a string
Tools:
--Chopsticks
--Tongs
--Turkey skewer
Challenge:
Remove 5 marshmallows from the strings.

Tuesday, March 22, 2011

Plate Tectonics: A Look Inside Folds and Faults

This is a great way to visualize what happens when rock layers are folded and subject to subsequent weather, erosion, etc.  The activity is based on this lesson.

You'll need four colors of play dough. 

Flatten each color into a rectangle about 1 cm thick.  Stack the layers on top of one another.  This is a good time to review which is the oldest layer (the bottom) and which is the youngest (the top). 

Push on two opposite ends of the play dough and watch your rock layers fold.  What kind of fold did you make?  (anticline)

Use a knife to slice some of the play dough off the top.  Look down - What do you see?  What do you think the layers look like on the inside? 

Slice through the play dough rock layers and observe the cross section.

Place the two halves back together, slightly askew, and you can see what happens to rock layers at a strike-slip fault. 


Monday, March 21, 2011

Mixing Colors: The Play Doh Version

Did you know you can use Play Doh to teach students about mixing colors?  A very tactile experience!

Start with two colors of Play Doh (I'd recommend beginning with primary colors, you can expand from there).  Use a small amount of each color.
 Knead the two colors together....

 You'll see the colors swirl together at first, and then combine to form a new color:

Here it is next to a sample of the original colors, so you can see what happened. 


You could have a lot of fun creating a Play Doh color wheel, or varying the amount of each color you used to create a whole range of shades. 

Friday, March 18, 2011

How Does That Work?: Gravity Defying Belt

 Can you balance a belt off the end of your finger?

How about off the edge of a table?

This is a lesson in an object's center of gravity.  When placed on a hook similar to this:
 a stiff belt (make sure it's stiff, a floppy belt or rope won't work) will curve under, so its center or gravity is directly below the point where the hook meets your finger (or the table), causing it to balance. 

Here's another picture of a hook - it doesn't have to be exactly the same shape as above.  And here's one that doesn't even look like a hook, but it still works.




Thursday, March 17, 2011

Acid/Base Chemistry: Mystery Solutions Lab

 I really enjoy this lab - it's like a big chemistry logic problem. 

This lab is one of the activities found at Science CAP (part of the ide@s website).  You'll need to visit the website to download and print the file, but I'll give you a brief synopsis. 

Before class, you prepare 12 sets of 4 dropper bottles (A, B, C, D).  The 4 bottles in each set contain an acid (vinegar), a base (ammonia), water and phenolphthalein.  Which substance goes in which bottle varies with each set - the provided materials include a chart so you know how to fill the bottles. 

Each team of students takes one set of bottles and a spot plate.  Using their knowledge of acids, bases and indicators, the students combine the substances (one drop at a time) in varying combinations to determine the identity of each substance. 

This activity can prove to be a bit challenging for some students, but encourage them to keep working to solve the problem and resist the urge to give away too much information.  Encourage students to review what they know about the substances:
--phenolphthalein turns pink in a base
--phenolphthalein stays colorless in an acid
--water does not change whether a substance is acidic or basic

In case you haven't figured it out yet, I highly value hands-on experiences for students.  Virtual is great and provides opportunities that students may not otherwise be able to have, but if both the hands-on activity and a virtual version were available, I'd choose hands-on each time. 

Now that you know my feelings on such things, I wanted to let you know there is a virtual version of this lab available.  I could see myself using the virtual version to introduce students to the activity and demonstrate how they'll be proceeding when they get to their lab stations. 


Wednesday, March 16, 2011

Body Systems: Skeletal System: Simon Says

I learned of this idea from one of my workshop participants and I think it's a fun one.

After your students have learned the names of the bones, play a game of Simon Says.

Pair off your students and call out commands such as "Simon says touch your humerus to your partner's femur." 

It well help solidify your students knowledge of the bones, as well as provide some good laughs for everyone.

Tuesday, March 15, 2011

Fossils: Digging for Dinosaur Bones

Keep your eyes out for puzzles similar to these (I've found them at Michael's, for only a buck or two each):

They're wooden sheets of pieces that you punch out and then assemble.  The paper inside the package tells you how to assemble the pieces, but you don't need it for this activity. 

Punch out the pieces for one dinosaur and bury the pieces in a bucket of sand.  Have students dig out the pieces and then try to assemble the pieces.  Without the instructions in front of them, they'll be working as paleontologists do, trying to determine how the bones go together. 

Some other ideas to consider:
*Mix up pieces from two different dinosaurs in the same bucket of sand - students have to determine which bones go with which fossil, as well as assembling them.
*Don't put all of the pieces in the bucket - you don't always find a complete skeleton in one place.
*Consider putting the pieces in something that requires more excavation than just pulling the pieces out of sand. 

Even if your curriculum doesn't include a study of dinosaurs and/or fossils, you can use this activity as a lesson on the way scientists work. 

Monday, March 14, 2011

Density: Penny Boats



How can you make a penny float?

Each student gets a 6" square of aluminum foil, with which he/she designs a boat that can carry a penny payload. 

The goal is carry a larger payload than anyone else.

There are several ways to present this activity:
--Each student gets one square of foil to make their boat and they compete with that original boat.
--Each student gets one square of foil, as well as access to water and pennies to test.  They then get a second square of foil to make their competition boat.
--Each student gets one square of foil, as well as access to water and an alternate payload.  They then get a second square of foil to make their competition boat.
--Each student gets a square of paper to use for design purposes.  They then get a square of foil to make their competition boat.

Depending upon how you choose to present this, you can make it a single day activity or a two day activity.

Friday, March 11, 2011

Science Wear

Photo from Science Wear
Science Wear makes these neat GUTS shirts.  They are a white shirt, with an outline of the organs screen printed on them.  Your students paint the shirts to make them their own, while reviewing some of the major organs.  The shirts are reasonably priced at $5 each, with free shipping if your order 25 or more.  There is a minimum order of 12.

If anyone who knows me (in real life) would like to get their hands on one or two shirts, let me know and we can put together an order to reach the minimum.  Or, even if you don't know me and just want one shirt, you can contact me and we'll see what we can do - obviously there would be some shipping involved, but less than ordering an extra 11 shirts that you don't really need or want anyway.  Leave a message in the comments (please leave your email address - they don't show up otherwise) or send me an email: adventures.in.science{at}gmail.com.

Science Wear also makes Atomic Attire (lab coats, aprons and t-shirts) and a Cell-ebrate Science t-shirt, but the GUTS shirt is my personal favorite.

Thursday, March 10, 2011

Heat Transfer: How Does it Feel?

A basic tenet of the study of thermodynamics (that's right, I said thermodynamics.  It's a big scary word, but really it just means anything having to do with the transfer of heat.  Of course, there's a whole lot more about it - you can spend semesters studying thermodynamics, but there's nothing wrong with calling your study of heat transfer thermodynamics.  In fact it'll make everyone involved feel that much more important) is that heat/energy flows from higher temperatures to lower temperatures.  Here's a way you can actually feel that principle at work.

You'll need three bowls:
--Fill one bowl with water and allow it to sit for about 5 minutes (or more) to reach room temperature.
--Fill the next bowl with water and add several ice cubes.  Stir.
--Fill the final bowl with warm tap water.  Aim for something that just feels warm on your wrist - you don't water so hot that it'll hurt you.

Arrange the bowls on the table so that the room temperature water is in the middle and the hot and cold water are on either side of it.

Place one hand in the warm water and the other hand in the cold water.  Leave them there for about 20 seconds. 

Remove your hands from the bowls and place them both in the middle (room temperature) bowl.  How do they feel?

Even though they are now in the same water, the hand that was in the cold water feels warm and the hand that had been in the warm water feels cold.  Why?

You placed your hand in warm water.  The energy (heat) moved from the water, which was hotter than your hand, to your hand, making it feel warm.  Then you placed it in water that was colder than your (now warmed) hand.  The energy (heat) left your hand and flowed into the water, leaving your hand feeling cold.


You placed your other hand in cold water.  The energy (heat) moved from your hand into the cold water.  When you placed that hand, with a reduced amount of heat energy, in the room temperature water, energy (heat) flowed from that water to you hand because there was more energy in the water than your hand.

Wednesday, March 9, 2011

Classification: A "Handy" Guide to the Kingdoms


This one falls into the category of "I wish I thought of that" - such a clever way to help your students remember the kingdoms. 


I can't really do the article justice, so you'll probably best be served to read it yourself, but I'll try to sum up:

Students trace their left on hand on their paper. 

If you have a green thumb, you're good with PLANTS

When you hold up your index finger while at a sporting event, you're saying ""We're number one".  Make the connection between one and mono and MONERA (bacteria).  (You'll have to combine the two kingdoms of bacteria into the one finger).

Pinky is for PROTISTS.  A small finger for small organisms.  The pinky has three segments, and there are three types of protists. 

The ring finger - if you don't wear a ring, you're not married, so you must be a fun guy.... a FUNGI (...pause for a collective groan...)

And finally, the finger the students have all be waiting for, curious to see how you're going to handle it.... Hold up your whole hand - which finger is the largest?  So that finger will be used for the kingdom with the largest variety of organisms and the largest individual organisms - the ANIMAL kingdom.  And if said finger is used inappropriately, it's called 'the bird'....

Tuesday, March 8, 2011

Constellation Viewer

These constellation viewers are pretty simple to make, once you've gathered your supplies.  You'll need a Pringles can for each viewer you want to make (ideally, one for each student).  I haven't found any good substitutions for this, but let me know if you do.  Put the word out early that you're collecting the cans, and you'll probably make out just fine.


Use a large nail to punch a hole in the bottom of the can.

 Cut out circles of black paper (and if you don't have any black paper, use another dark color, like blue).  The circles should be the size of the can.

Place a diagram of the constellation you want on top of one of the circles and use a nail to poke a hole at each star.  Some nice diagrams (the same size as the circles you're using) are found here

After all the star holes  have been poked, place the paper in the can lid.

Then place the lid on the can (or the can on the lid, which may be easier, as pictured below), sandwiching the paper inside. 

Hold the can up to the light and look through the hole in the bottom of the can to view your constellation.  (Wish I could get a picture of what it looks like, but you'll just have to make one yourself).

You may want to write the name of each constellation on the back of the paper - that way you'll be able to see the name through the lid while it's inside:

Also, unless you're well-versed in constellations, you may want to draw in the lines of the constellation to help you identify what you're looking at.

Monday, March 7, 2011

Graphing: Class Data

A day or two before you want to have the students create the graphs, have the students complete a questionnaire.  Here are the questions I've asked (it provided me with enough data for groups of students in 3 classes):

  • In which month were you born?
  • How many siblings do you have?
  • What's your favorite color?
  • Whats your favorite food?
  • What's your favorite TV show?
  • What's your favorite movie?
  • What's your favorite book?
  • What's your favorite subject/class?
  • What's your favorite sport?
  • What's your favorite outdoor winter activity?
  • What's your favorite outdoor summer activity?
  • What's your favorite season?
  • What's your favorite restaurant?
  • Who's your favorite musician/band?
  • What's your least favorite vegetable?
  • What color are your eyes?
  • In which state were you born?
  • How do you get to school?
  • What's your zodiac sign?
  • What pets do you have?
  • What do you want to be when you grow up?
 

 
Cut the responses apart and put them in groups.

 
Divide students into groups and provide each group with one set of data. 

 
Students sort data and decide on an appropriate way to graph it.

 
Some of the data sets will require more work than others.  Some of it will need to be put into groups before it can be graphed.  For example, you will probably get a large variety of responses for "What is your favorite restaurant?", so the students may need to graph types of restaurants (i.e. Italian, Chinese, fast food, etc.) rather than specific restaurant names.  On the other hand, "What's your favorite season?" is pretty straight forward and easy to graph. 

Friday, March 4, 2011

Website: ide@s

ide@s is a collection of classroom tested lessons, sponsored by the University of Wisconsin Extension and the University of Wisconsin System.  You can search for lessons in all curriculum areas, which will interest those of you who teach more than just science. 

For the purposes of this blog (and my own interests), I'll direct you to Science CAP portion.  I haven't counted, but the site claims (and I have no reason to doubt it) over 2000 pages of activities, assessments and resources for teaching middle school science.  Like most things, many of these activities can be adapted up or down to meet students in other grade levels.  In a week or so, I'll provide you with more details about one of the activities from this collection that I've successfully used. 

A few more interesting things about ide@s...

If you currently teach in Wisconsin (any grade, pre-K through 12), you can apply to be part of the ide@s research team. As part of the team, you will test 2 resources per month in your classroom and then provide feedback on the resrouces' effectiveness.  I do not have any first-hand experience with this program, but I think it could be interesting to look into.  For me, it would probably depend upon how extensive the feedback process was and how much time was required to complete it. 

ide@s also offers a nice collection of copyright-free digital images for educators to use for free within their classroom.

Several resources in one place - you can't go wrong with that!

This post is linked up with:
Favorite Resource This Week

Thursday, March 3, 2011

Atoms/Periodic Table: Bingo

Have students fill in a blank bingo card with any numbers between 1 and 50.

You can make up your own clues involving elements' atomic numbers, protons, electrons, and neutrons, or you can use mine:

1 - # of protons in Hydrogen
2 - # of neutrons in Helium
3 - # of electrons in Lithium
4 - # of neutrons in Lithium
5 - # of protons in Boron
6 - atomic number of carbon
7 - # of neutrons in Nitrogen
8 - # of electrons in Oxygen
9 - atomic mass of Beryllium
10 - # of protons in Neon
11 - atomic number of sodium
12 - atomic mass of Magnesium
13 - # of in Aluminum
14 - # of protons + # of neutrons in Nitrogen
15 - # of protons in Phosphorous
16 - # of protons in Sulfur
17 - # of electrons in Chlorine
18 - # of neutrons in Chlorine
19 - # of protons + # of neutrons in Fluorine
20 - # of neutrons in Potassium
21 - atomic number of Scandium
22 - # of protons in Titanium
23 - # of protons + # of neutrons in Sodium
24 - atomic mass of Magnesium
25 - # of electrons in Manganese
26 - # of neutrons in Titanium
27 - atomic number of Cobalt
28 - # of protons + # of neutrons in Silicon
29 - # of protons in Copper
30 - # of protons in Zinc
31 - # of electrons in Gallium
32 - atomic number of Germanium
33 - atomic number of Arsenic
34 - # of protons in Selenium
35 - # of neutrons in Zinc
36 - # of electrons in Krypton
37 - atomic number of Rubidium
38 - atomic number of Strontium
39 - # of protons in Yttrium
40 - atomic mass of Argon
41 - # of electrons in Niobium
42 - # of neutrons in Arsenic
43 - atomic number of Technetium
44 - # of protons in Ruthenium
45 - atomic mass of Scandium
46 - # of  electrons in Palladium
47 - # of electrons in Silver
48 - # of protons + # of neutrons in Titanium
49 - atomic number of Indium
50 - # of protons in Tin
I recommend making up a list ahead of time, to make sure you don't use the same number over and over while completely skipping others.

I wrote my clues on index cards.  Then, for each round I shuffle the deck and draw the cards from the top.

Wednesday, March 2, 2011

Adaptations: Bird Beaks - Version 2

Sorry, I didn't get all the materials together to take pictures to adorn this post, but I promised it was forthcoming and wanted to share before too much time had passed.  

This version of the bird beak activity has 6 stations.  At each station, students will use 3 different beaks/tools to collect the food featured at that station.  The goal is to determine which beak is the best matched to the food source.   (For a simpler version of this activity, see here). 

Students will try each beak for 15 seconds.  The collected food will be placed in a cup, and then returned to the supply.

Station 1:
Nectar: water in a graduated cylinder
Tools:
--Clothespin
--Medicine dropper
--Pipette

Station 2:
Worms: gummy worms in sand
Tools:
--Straw
--Chopsticks
--Clothespin

Station 3:
Seeds and Nuts: sunflower seeds, etc.
Tools:
--Chopsticks
--Tweezers
--Pliers

Station 4:
Aquatic Plant Life: aquarium plant in water
Tools:
--Pliers
--Tweezers
--Pipette

Station 5:
Insects: rice stuck into a styrofoam log
Tools:
--Tweezers
--Chopsticks
--Pliers

Station 6:
Fish & Water Animals: beads & plastic fish in water
Tools:
--Tongs
--Tweezers
--Chopsticks

Tuesday, March 1, 2011

Plate Tectonics: Candy Bar Faults

The fastest way to get your students' attention is to break out the candy!

You'll want to use candy bars that have a pliable inside and are coated in chocolate - think Snickers, Milky Way, 3 Musketeers.  The chocolate represents the Earth's crust and the filling represents the asthenosphere.

Use your fingernails to break up the chocolate crust - creating the fault.

Demonstrate tension by pulling (slowly and only a small amount) on the two ends of the candy bar.  Notice how some of the asthenosphere is revealed.

To demonstrate shearing (strike-slip faults), push the two sides of the candy bar back together.  Then slide one half forward while pushing the other one back.

Finally, to demonstrate compression forces, push the two ends of the candy bar together.  You'll see the pieces of chocolate crust colliding and maybe even sliding over each other, creating mountains.