Fig. 7.62. Diagram of folded paper channel for sediment cores
Image by Byron Inouye
Title
Activity: Sediment Cores
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
NGSS Disciplinary Core Ideas
Table of Contents
Materials
- Table 7.7
- Sediment of various grain sizes (e.g., fine sand, clay, soil)
- Several small buckets
- Small plastic container
- Water
- Three large bore clear plastic straws (bubble/pearl tea type)
- New unsharpened pencil
- Centimeter ruler
- Three sheets of blank white paper
- Tray
Procedure
A. Plan your sampling.
- Obtain a plastic container filled with damp sediment from your teacher.
- Fold one sheet of paper lengthwise in thirds. The folded paper should form a V-shaped channel similar to the one shown in Fig. 7.62.
- Repeat paper folding for remaining sheets of paper to produce three V-shaped paper channels.
- Discuss with your group where you are going to take your sediment cores. Write down your sampling procedure.
- Make predictions about what you will find in each sample core based on information from your teacher.
B. Collect sediment cores.
- For the first sediment core, push the straw into the sediment at your desired location. Push the straw straight down as deep as possible.
- Firmly place your thumb over the open top end of the straw to form an airtight seal inside the straw. Gently pull the straw up and out of the sediment while maintaining a firm seal over the top of the straw. The straw should be filled with sediment.
- Place one paper channel on the tray. Position the open end of the straw over the paper in the middle of the V-shaped channel. Release your thumb seal from the top of the straw. Use the eraser end of the pencil to gently and slowly push the sediment out of the straw and onto the open V-shaped paper channel.
- Label the paper containing the sediment core.
- Repeat Steps 1–4 for remaining two cores.
C. Observing sediment cores.
- For each core, identify the different layers.
- Record observations of material properties, such as size of sediment, moisture, and color in Table 7.7.
- Measure the thickness of each layer; record in Table 7.7.
- Calculate the average thickness for each layer.
Activity Questions
- How do you think this activity models taking ocean cores?
- What are the limitations to this model? (Hint: Think about how taking real ocean cores are different than this activity.)
- Explain how you selected your sediment sampling locations (where the straw was pushed down).
- Did your predictions match your observations? If they did not, explain why you think they did not.
- Were all of the sediment core samples the same? Why do you think they were similar or different?
- If your sediment cores were taken from an actual ocean floor, which layer would be the oldest? Which layer would be the youngest?
- Share your procedure for achieving the best quality sediment cores (most complete in cylindrical form).
- What inferences can you draw about the sediment in your container?
