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In Indiana, when it comes to Mother Nature's storm, we brace for blizzards and tornadoes more so than an earthquake. But, understanding all types of natural disasters helps us prepare and stay safe. Did you know earthquakes can occur at any time of the year and under any weather conditions? This means buildings and other structures need to be ready for an earthquake at anytime.
In this week’s Saturday Science experiment, from education.com, discover how soil liquefaction affects the stability of buildings during an earthquake.
Materials
- 4’ x 4’ board
- Five tennis balls
- A deep plastic basin (one you won’t need to use again)
- A bucket of sand
- A bucket of gravel
- A bucket of clay soil
- Lego-tyle plastic bricks
- Stopwatch
- Two ¾” screws and washers
- Drill
Process
- Have an adult drill two 3/8” holes into the middle of the dish basin 6 inches apart.
- Center the dish basin on top of the 4’ X 4’ board. Insert and tighten the ¾” inch long screws through the washers and into the screw holes of the basin and the board.
- Carefully balance the 4’x4’ board, basin side up on the 5 tennis balls. This is your shake table.
- Build a tall structure with your Lego bricks.
- Fill the basin to the top with sand. Place the Lego bricks structure into the sand, burying approximately 1 to 2” of the base of the structure in the sand.
- Start the stopwatch, and begin to vigorously shake your shake table. When your Lego bricks building falls, stop the stopwatch.
- How long can you shake the table before the structure topples?
- Repeat steps 5 to 7 using clay soil and then a gravel and clay mixture.
Summary
Which soil supported your Lego bricks building best? Which supported it the worst?
When you shook your shake table, you mimicked an earthquake by applying stress to the soil beneath your Lego bricks building.
When soil loses its strength and stiffness due to this type of stress, it is called soil liquefaction. This phenomenon typically takes place when sandy soils become saturated, meaning the space between the individual particles fills with water. Soil liquefaction decreases the strength of the soil, making it more difficult to support buildings and other structures like bridges.
Want more Saturday Science? See all of our at-home activities on the blog or on Pinterest.
