Sounding Box Activity


Part 1: Making a Sounding Box:

1 box - shoe box or a small box from a grocery store

Surprise sea floor items - You can use rocks, gravel, dirt, and sand with different shaped objects to represent the various surprises found during surveying.

Items to sink - Legos, toy planes, and small boats are all good ways to represent airplanes and ships that sometimes sink and come to rest on the ocean floor.

"Pretend" water - Blue Air Filter or aluminum foil are the best ways to represent the water surface. Label each side of the filter or aluminum foil with a grid that matches the attached plotting chart. Cover your box with the filter or aluminum foil and add the labeled grid on top to complete your sounding box. Now you are ready to take measurements.

Make a delicious sounding box - If you’re interested in making your sounding box an irresistible snack, you can use graham crackers, candy, and Jell-O to make an edible version of your sounding box.

set up for sounding box activity
These are the materials that you will need for this activity.
  placing items inside the box Step 1: Be sure to have a copy of the depth chart grid. placing items inside the box Step 2: Place your items on the bottom of the "sea floor."
  placing items inside the box example of items inside the box
  Step 3: Space your items around on the bottom. This is an example of what your "sea floor" may look like before you put the “pretend” water on top.
  More Examples of "Sea floor" Sounding Boxes
  example of items inside the box
This box has a sloping bottom with ship hulls.
example of items inside the box
This box has 2 levels with rocks and a sponge.

Part 2: Taking Measurements


Materials for taking measurements:

Sounding box covered with aluminum foil (see above)

Long, skinny stick: bamboo skewer, long pencil, knitting needle, or a dowel

2 copies of “Depth Chart” grid - download (pdf, 62Kb) and print out 2 copies

1 copy of a “Color Coded Depth Scale” - download (pdf, 27Kb) and print out 1 copy



What to Do?


color scaleStep 1 - Have your “Color Coded Chart” ready: color each grid that is next to a number in a different color of your choice. Example: #1 – Red, #2 – Orange, etc.

Step 2 - Get a copy of the “Depth Chart”.
Get a small sharp object. Poke a small hole in each square of the “Depth Chart” so that you can easily push your bamboo skewer through each square of the grid. Tape the “Depth Chart” on top of the aluminum foil that covers the box.

depth chart

Step 3 -Position the stick carefully into the first spot you want to sample. (grid 1,1 )

Step 4 - Measure “depths” by gently pushing the long and skinny stick through the Depth Chart and cover of the sounding box until the stick hits something on the bottom.

gently pushing the rod through the blue mesh or alluminum foil
Start at one corner to take measurements of each depth.


Step 5 - Pinch your fingers around the stick where it is even with the cover.

Step 6 - Measure the distance from the end of the stick to your fingers using the Color Coded Chart. What is the color that corresponds to that distance?

Measure the distance from the end of the rod to your fingers using the measurement scale

Step 7 - On your second copy of the “Depth Chart,” color the first grid  (1,1) with the color that corresponds to the distance that you measured.

Step 8 - Repeat steps 4-7 at each point marked on the grid on the box. Record each measurement in the proper place on the depth chart.   

making more mesurements
  For each measurement, find the color that matches the depth you just found. Take a measurement at each hole on the grid.

example of depth chartNote - When you have finished, each square on the Depth chart should be colored. (See the example here and below.)

example of depth chartStep 9 - Draw lines that connect grid boxes that have the same colors to show what objects or landforms are on the bottom of your Sea floor. (See example here and below.)



Step 10 - Carefully take the aluminum foil off and compare your plotting sheet to the bottom of the box. Did you find all of the objects or landforms on the bottom of your Sea floor?  Why or why not?

  Example of a completed "Sea floor" Chart for Step 8 Example of a "Sea floor" Chart for Step 9
  example of completed seafloor chart for step 8 example of seafloor chart for step 9

...and this is what the real sea floor scan looks like...


Here is a scan of an oyster bed.
example of oyster bed scan

Here is a scan of a ship.
example of oyster bed scan


Great Job! Use your plotting sheet to think of what the bottom of the box may look like.

Imagine how the bottom of the box may resemble the sea floor and answer the following questions:

    The NOAA safety seagull
  1. What type of old hydrographic surveying method is most like the sounding box activity?

  1. Do you think we still have charts that use information from lead line surveying?

  1. What could happen if the depth information we have from old surveys is out of date?

  2. Look at the different depths you marked on your plotting chart.  What was the shoalest, (the most shallow), depth you found?

  3. If you were a boat, do you think your chart would have safely helped you across your ocean?
    Why or why not?


Proceed to Sunken Treasure Activity!