Stalagmites & Stalactites

BY:Bristol Lacey

Big Question

Which will grow faster, the stalagmite or the stalactite?

Stalactites grow downwards and the stalagmites grow upwards.

HypothesisIf the pull of gravity helps a stalactite

grow, then a stalactite will grow faster than a stalagmite. The stalactite will

grow faster because it grows downward and the stalagmite grows upward.

Interesting Facts • Stalagmites grow very slowly in caves but quite fast in

basements or artificial caves• Stalagmite from the Greek language means ‘drop or

drip’• If a stalagmite and a stalactite touch it is called a column • Paleoclimatologists can use stalagmites to study the

climate pattern like rainfall like 20,000 years ago by studying the rings inside of it and knowing how fast it grows.

• Drips over time build up stalactites

Experiment Materials

• Two one-pint jars• dish towel• 8” round dish• spoon • masking tape• ruler• one cup sodium carbonate• scissors• pencil• notepad

Experiment

M a t e r i a l s … … . . c o n ti n u e d• t h r e e s h o r t p i e c e s o f s t r i n g• g r a p h p a p e r• o n e p i e c e o f p r e s s b o a r d ( 1 5 ” x 2 0 ’ ’ )• t w o p i e c e s o f 1 4 ” l o n g 2 X 4 w o o d• 2 - 3 / 8 ” t r i m • 4 - 1 ” s c r e w s• 2 L b r a c k e t s• 1 / 4 ” r o u n d a l u m i n u m p i e c e• 7 / 1 6 ” s p a c e r 1 ¾ ” i n d i a m e t e r• d i g i t a l c a m e r a• 4 c u p m e a s u r i n g c u p• a n d 4 c u p s o f h o t t a p w a t e r.

Experiment Procedures

• Devise a system to place the camera on so that it takes a picture from the same place every time.

• Attach a piece of graph paper to a 15” x 20” pressboard, make sure you can see graph lines with the camera.

• Place a flat surface above a dish and adjust it to eye level of the camera.

• Using hot tap water fill both jars almost to the top.• Add one half cup sodium carbonate to each jar, stir

until no more will dissolve.

Experiment Procedures…….continued

• Tightly twist the dish towel, and then tie a short piece of string around each end and one in the middle of the dish towel.

• Make a bridge between the two jars using the twisted dishcloth being sure the ends reach the bottom of each jar.

• Place the dish between the two jars in front of the graph paper.

• Observe daily watching the stalagmite and stalactite to form.

• Observe daily and note changes taking digital photos.

Experiment Controls VS. Variables

All procedures are controlled (identical) for both the stalagmite and stalactite groups. There are no variables imposed. Gravity and evaporation are the influences of change we expect to see.

Observations

• The water came up about half way, soaked into the towel and dried up.

• The towel was coated with a chalk white crust.

• It became dry and hard like a rock.• Neither a stalactite nor a stalagmite formed.• Plus, I think that it choked itself off at the lip

of the jar.

Observations……continued

• This time, the water moved quickly (over 2-3 days) up the towel and again only traveled to the string.

• The string became dry and stiff.

Observations

(the first bridge)

Observations

(Day after day)

DATA (FIRST EXPERIMENT)1ST DAY THERE WAS NO VISIBLE CHANGE. (OCTOBER 27TH)

2ND DAY THE SOLUTION SOAKED UP SLOWLY UNTIL IT REACHED THE LIPS OF THE JARS. (OCTOBER 28TH)

3RD DAY THE SOLUTION SOAKED ACROSS THE BRIDGE AND STOPPED AT THE STRING. (OCTOBER 29TH)

4TH DAY THE SOLUTION ON THE TOWEL TURNED CHALKY WHITE AND BEGAN TO HARDEN. THE STRING REMAINED DRY. (OCTOBER 30TH)

5TH DAY BRIDGE BECAME HARD AS A ROCK AND TURNED CHALK WHITE. STILL NO SOLUTION ON THE STRING. (OCTOBER 31ST)

6TH DAY NO INDICATION OF FORMATION. (NOVEMBER 1ST)

7TH DAY NO CHANGE (NOVEMBER 2ND)

8TH DAY NO CHANGE (NOVEMBER 3RD)

9TH DAY NO CHANGE (NOVEMBER 4TH)

Data (Second experiment) 1st day There were no visible changes. (November 5th)

2nd day The solution soaked all the way across the bridge and began to turn chalky white. (November 6th)

3rd day The dishcloth began to harden and the string hadn’t soaked up any solution. (November 7th)

4th day The bridge continues to harden, and then I dripped solution onto the string. (November 8th)

5th day The solution didn’t continue to flow down the string. The string began to harden also. (November 9th)

6th day No change (November 10th)

7th day No change (November 11th)

ANALYSIS OF DATA

My experiment didn’t test my hypothesis. Both times I did my experiment neither a stalagmite nor a stalactite formed, so I don’t know which would grow faster.

Conclusion Neither of my experiments produced any

stalagmites or stalactites. Therefore, I was unable to prove or disprove my hypothesis. Next time, I would use distilled water instead of tap water, to reduce minerals and chemicals that might have interfered. I would use a more absorbent string to improve the flow of the solution.

Some questions I have:

• How do the big rooms in caves get so big?• Do other planets have stalagmites and

stalactites like earth?

References • http://en.wikipedia.org/wiki/Stalagmite (September, 2009)

Stalagmite• http://www.enotes.com/earth-science/stalactites-stalagmites

(September, 2009) World of Earth Science/Stalactites and Stalagmites

• http://www.jimloy.com/geology/stalac.htm (September, 2009) Stalactites and Stalagmites

• http://www.pbs.org/newshour/bb/science/jan-june09/rainfall_06-02.html (September, 2009) Stalagmites Provide Clues in Changing Rainfall Patterns

• http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0007811.html (September, 2009) Stalactite and Stalagmite