Students will build a city out of sugar cubes, bouillon cubes, and gelatin cubes. The city will be put through simulated earthquakes to see which cube structures withstand the shaking the best.

LEVEL OF DIFFICULTY [1 = Least Difficult : 5 = Most Difficult]

1-least difficult

TIME REQUIRED

20 minutes for construction
30 minutes for testing

COST

$5.00

2.5 Explain how such design features as size, shape, weight, function and cost limitations (i.e., ergonomics) would affect the construction of a given prototype.
1 .1 Given a design task, identify appropriate materials (e.g., wood, paper, plastic, aggregates, ceramics, metals, solvents, adhesives) based on specific properties and characteristics (i.e., weight, strength, hardness and flexibility).

The effect of earthquakes on structures.
The importance of strong buildings to prevent destruction by earthquakes.
How the epicenter of an earthquake affects buildings.
Different materials may be used in the construction of buildings.

When there is an earthquake, energy travels through the earth and can cause damage to buildings and other structures far away. The amount of damage caused by an earthquake depends on several things such as the strength of the earthquake, how long it lasts, and where it happens.
The epicenter of an earthquake is the point on the earth's surface directly above where an earthquake starts, or where the shaking begins. The damage will typically be the greatest at the epicenter.
Today, some skyscrapers are made of more flexible materials so that they bend and sway during an earthquake and do not fall down as easily.

RESOURCES:
http://earthquake.usgs.gov/4kids excellent resource for more background information on earthquakes.
Books: Earthquakes by Seymour Simon; Mulberry Books, April 1995

Box with smooth bottom, at least 25-cm wide X 20-cm long
Sugar cubes
Bouillon cubes
Gelatin cubes (Follow instructions on box to make, but use 1/3 as much water as the recipe calls for. Use a pan or ice cube tray. Chill until very firm and cut into small cubes, about the size of sugar and bouillon cubes).
Pencil
Ruler
(Optional: wood and plastic cubes as additional building materials)

Buy or assemble materials
Prepare gelatin cubes
Discuss with the class what an earthquake is and what the epicenter of an earthquake is.

DIRECTIONS:

1. Split the students into small groups or pairs and give each group a box bottom.
2. Using the pencil and ruler, have the students create a grid on the box by drawing 4 vertical lines and 5 horizontal lines; each line should be 5-cm apart. Label the vertical lines 1st Avenue, 2nd Avenue, 3rd Avenue, etc., and the horizontal lines A Street, B Street, C Street, etc. This is the earthquake city.
3. To show that earthquakes can cause damage to buildings, have the students build three sugar cube skyscrapers, each one five sugar cubes tall. Build the skyscrapers at the following corners: A and 1st , B and 2nd , C and 3rd .
4. Now have the students simulate an earthquake by tapping on the corner of D and 4th with the eraser of a pencil. They should continue to tap until at least one cube from each skyscraper falls. Ask: Which skyscraper falls first? In a real earthquake, do you think more damage would happen in one place than another? Where would the most damage happen?
5. The students should try step 4 again, but use different strength taps, representing hard vibrations and soft vibrations. They should determine how many hard or soft vibrations it takes to knock over buildings different distances away from the epicenter.
6. Have students record results in a chart containing the location of the skyscraper and when it fell.
7. Now allow the students to experiment with different types of cubes. Encourage them to create skyscrapers from a variety of blocks and of different heights.
8. After they have had time to experiment with the different types of blocks, each group should build a city of skyscrapers. The cities may be as large as they wish but must have at least five skyscrapers of different heights.
9. Once they have completed their cities, go around to each group and tap with your pencil at a corner in the city to test how earthquake resistant they are.
10. After the cities have been tested, students should put away materials and you can have a discussion about what the students discovered.

Why is it useful to build skyscrapers out of different materials?
Which materials were the best to use for taller buildings?
Which cubes were the most earthquake resistant? Why?
Which skyscrapers fell first in the earthquakes? Where were they located in respect to the epicenter of the earthquake?
What happens when the top of a skyscraper is heavier than the bottom, or when the bottom is heavier than the top?

Kessler, James H. and Andrea Bennett. The Best of Wonderscience: elementary science activities. Boston: Delmar Publishers, 1997. ISBN: 0827380941 p. 322-324.*
*Adapted with permission from The Best of Wonderscience, Copyright 1997, American Chemical Society Published by Wadsworth Publishing, Inc.. If you enjoyed this activity check out www.chemistry.org/wondernet, Your Science Place in Cyberspace, for free elementary physical science activities.

WORKSHEETS:

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SAMPLE RUBRIC:

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