Utah Science Homepage

Earth Systems
Inquiry Activity

DESCRIPTION OF ACTIVITY:

TITLE - SHAKE, RATTLE AND SINK

Overview
Students will explore the idea and properties of LIQUEFACTION through the use of Ooblick

Duration of Activity - 30 minutes

Materials, facilities, and resources
· Ooblick (two parts corn starch to one part water)
· Plastic shoebox or plastic box,
· Newspapers on floor and tables (however it is easy to scrape after it dries)
· Blocks of wood of different shapes and weight.
· Other objects of differing shapes, sizes, and weights (that would fit into the shoe box).
· Paper and pencil
· A local map of liquefaction probability during earthquake activity, if available.

BACKGROUND INFORMATION:

· This is a good introductory exploration for either a unit on ground water or earthquakes.
· Liquefaction is the changing of properties of a solid upon the addition of water.
· Some solid soils will turn to quicksand-like material if just the right amount of water is added to them. Sand is notorious for this. In the case of liquefaction, the water comes from the ground water underneath. If the water table is relatively shallow and close to the surface it happens quickly. During an earthquake, it is like mixing water and oil and you get salad dressing.

TEACHING AND LEARNING STRATEGIES:

Ensure Inquiry
Students will use various weights and movements to discover the properties of liquefaction which happens when ground water seeps into, and saturates the soil. It is an exploratory activity so you do not want to give any information about what they will find out.

Prerequisite Instruction
Only tell the students that they are going to see what
happens when ground water saturates the soil above it. This can happen in old stream beds or during the shaking of an earthquake.

INVITATION TO LEARN:

Problem: To construct a liquefaction model and determine the problems associated with liquefaction during seismic activity.

Instructions:
1. The teacher will give each group of three to four students a box containing dry corn starch (about two to three cups), and a glass of water (about 1 1/2 cups). They should not mix the ingredients until told to do so.
3. Ask the students to write down as many characteristics about the dry corn starch "soil" as they can discover. (They may use anything from the table of materials.)
4. Add the water to the corn starch from one corner. Do not mix. Observe and record any new characteristics of the mixture.
5. Tell the students to shake the box from side to side and record new characteristics (Explore with materials available).
6. Ask the students to mix the corn starch and water thoroughly with their hands. and observe and record new characteristics.
7. Instruct the students to explore what happens when objects of different shapes and weights are placed on top of the mixture
8. Tell the students to list places and occurrences where the same thing might happen in nature.
9. Have the students record recommendations for overcoming the problems associated with liquefaction.

Safe Operating Procedures
· Remind students to keep their hands over the boxes and newspaper so they don't spill on the floor. They may want to wear aprons to keep mixture off their clothes.
· Once the Ooblick dries, it can easily be cleaned up with a putty scraper and swept away. Do not try wet paper towels.

SUMMARY OF LEARNING:

Assessment
Ask students to share their observations on the board. Have the class discuss locations, problems, and solutions for liquefaction. Relate this activity to local or regional areas of possible future earthquake activity.

Suggested questions
1. What were the differences between the dry "soil" and the "liquefied soil"?
2. Which type of soil could hold more weight?
3. When did the "soil" become more mixed, when it was allowed to soak, or when you shook the box?
4. Do you think this could happen quickly or slowly during an earthquake?why?
5. Why would it be dangerous to ride cars or motorcycles along old riverbeds? What is this stuff called? (quicksand)
6. If you are stuck in quicksand while out riding what is the best way to escape? Does this apply during liquefaction in an earthquake?
7. How could people build or deal with this problem if they know they are in an area where liquefaction could happen?

Multiple choice questions
1. What areas of the Wasatch Front would experience liquefaction? Areas on
A. bedrock
B. sand
C. clay
D. gravel

2. What type of buildings would do better on potential liquefaction soil?
A. One story, spread out buildings
B. Narrow, linear buildings
C. Tall, skyscraper-type buildings
D. Buildings made with heavy materials

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This document was submitted for posting to the Internet by the State Science Specialist. Any questions concerning content should be directed to that individual.

Updated September 18 1997 by Michelle Dumas