In this activity, students simulate the techniques oceanographers use to explore and map the sea floor. Using "sounding rods" and a grid system, they gather data to create a three-dimensional model of an unknown ocean landscape. This hands-on experiment introduces concepts in sonar mapping, underwater landforms, and marine technology.
Transcript
Text Transcript
In this video, we will simulate how oceanographers explore and map the seafloor. We will gather data point by point and build a three-dimensional model of an underwater landscape. For this activity, we will be using a box with a seafloor structure inside. Here we are using a box that has already been prepared with grid points and a ruler. If you want to do this at home, you can make your own using a shoebox and use clay or foam to create the seafloor shape. We will also need a measuring stick to use as a sounding rod. You can use wooden skewers, but be careful with the sharp points or trim them off for safety. Additionally, we will use a cardboard base that is about six and a half inches wide and five inches tall, along with graph plotting grids where we can record the data. Finally, we will need scissors, glue, and markers. To begin the activity, prepare the base of your model. Cut out one grid from a graph plotting page and paste it onto your cardboard base. This grid will serve as the guide for where each profile will be attached. If you are using NOAA materials, each box will have a letter on the bottom, so label your base with that letter. This is important because each box will have a different seafloor shape. Now, let us start collecting data points. We will begin at row zero and work our way down the box, skipping row ten. Use a new grid for each row and label it with the row number so you do not lose track. On each row, start from the left, locate zero, and insert your rod straight down at a ninety-degree angle until it touches the surface of your seafloor. To mark the depth, pinch the part sticking out above the box with your fingers. Then carefully remove the rod while keeping your fingers in place. Use the ruler in the box to measure from your finger mark to the bottom end of the rod. In this example, the speaker recorded a depth of ten centimeters. Then go to the grid, find column zero, and make a dot at the ten centimeter point. Move to the next point on the row and repeat the process. Insert the rod, mark the depth with your fingers, measure, and plot the point on your grid. Continue until all points in row zero are finished. Keep in mind that some depths may fall between grid points, so mark them at the halfway point, as shown in the video. Once all the data is collected, connect the dots across the row to form your profile line. When you are done with row zero, move on to the next row and repeat the same process. Do not forget to label your profile so you do not lose track. The speaker will keep collecting data row by row, building one profile at a time until there is a total of ten profiles. After completing all the profiles, it is time to cut them out to start building the three-dimensional model. Cut along the bottom line of the grid and across the red line of your profile. To stay organized, you can write the row number on the back of each cutout. Now, to assemble the model, start with profile nine. Fold along the bottom line of the grid, apply glue to the strip, and paste it to the bottom row of your base. Repeat the process with profile eight, folding, applying glue, and pasting it to the row just above profile nine. Continue backward through each profile, finishing with profile zero to complete your three-dimensional model. When your model is finished, open the box and look inside. Compare your reconstructed seafloor with the hidden structure. Just like real oceanographers, you gathered indirect measurements to map a landscape you could not see. Each skewer acted like a sonar beam, giving you one depth reading. By combining many data points, you created a three-dimensional picture of the seafloor. For more activities and resources like this, visit the NOAA Office of Education website.
Grade range: 6 – 12
Setting: Classroom or outreach events
Estimated Time: 45-60 minutes
🌊Background
The sea floor is the bottom surface of the ocean and contains various landforms shaped by geological activity. These include:
- Mid-ocean ridges: Long underwater mountain ranges formed by rising magma that cools and hardens.
- Rift valleys: Deep cracks that run through mid-ocean ridges, where tectonic plates diverge and new crust forms.
- Trenches: Deep, narrow areas formed when one tectonic plate is forced under another.
- Sea mounts: Underwater volcanic mountains rising from the ocean floor, sometimes becoming islands.
- Guyots: Flat-topped sea mounts that were eroded by wave action before submerging below sea level.
Scientists use SONAR (SOund Navigation And Ranging) to map these hidden landscapes. A sonar device sends sound waves that bounce off the ocean floor; the time it takes for the echo to return reveals depth and shape.
🧪Materials
- Boxes with “unknown” sea floor structures inside
- Note: in this video, we use a pre-made kit, but you can make your own using shoeboxes and clay
- Skewers (to simulate sounding rods)
- Cardboard squares (for 3D model base)
- Graph plotting grids (11 per group)
- Pens or markers
- Glue sticks
- Scissors
🧭Instructions
- If using a pre-made kit: Prepare the base of your 3D model. Cut around one graph plotting grid and paste it onto a cardboard square. Label the top of your base with the letter found on the bottom of the assigned sea floor structure box.
If creating your own: Watch the video for inspiration. Use clay to create a varied seafloor in the bottom of a shoebox. Include hazards for ship travel, such as shallow reefs. Allow it to dry and harden. Tape a piece of graph paper to the top of the shoebox lid and tape the lid in place so that the shoebox cannot be opened easily. Label the grid on the graph paper, latitude and longitude. - Take a new blank graph plotting grid and start your activity from the first row.
- Locate coordinate (0,0) on the top of your box.
- Insert the sounding rod straight down into the hole at (0,0) until it touches the hidden structure inside. While the rod is still inserted, pinch the part sticking out above the box with your fingers to mark the depth.
- Carefully remove the rod while keeping your fingers in place. Use the ruler in the box to measure from your finger mark to the bottom end of the rod. Record this depth.
- On your graph plotting grid, find coordinate (0,0). From the top of the grid, count down the number of centimeters measured and place a dot to represent the depth. Example: If your depth was 9 cm, place a dot 9 squares down from the top.
- Repeat steps 4–7 for all points in Row 0: (0,1), (0,2), ..., up to (0,15). Use a new graph plotting grid for every row.
- Connect the plotted points across the row to form a line. Cut along the plotted line, then fold the strip along the bottom edge (Row 10). Glue the folded strip onto the matching row on your cardboard base.
- Do the same for all rows (skip Row 10), building your seafloor profile layer by layer.
- Once your 3D sea floor profile is complete, open your assigned box and look at the hidden structure inside. How does it compare to the model you built? Does your profile match what you see?
💡What is happening?
Just like real oceanographers, you are using indirect measurements to map a landscape you can’t see.
- The rod acts like sonar: probing the "seafloor" to detect how deep it is.
- Each coordinate gives one piece of data, and multiple readings build a larger picture.
- By plotting depths on a grid, you reconstruct the underwater landforms in 3D.
Oceanographers rely on similar sonar data to create bathymetric maps of the ocean floor, from shallow coasts to deep trenches.
🔍Scientific connection
The ocean floor remains one of the least explored areas of Earth. Harsh conditions like darkness, cold, and extreme pressure make it difficult to access. That’s why scientists use technology such as:
- SONAR: Technique that sends sound pulses to determine depth.
- Submersibles: Robotic or manned vehicles used to explore extreme depths.
- Satellites: Orbital instruments in space that collect large-scale elevation data.
- Remote sensors: Devices that can detect underwater features from afar.
Your model simulates the way data points are turned into bathymetric maps, which are crucial for navigation, environmental monitoring, and ocean research.
⚠️Safety notes
- Handle scissors and skewers carefully.
- Remind students not to force the skewers through the box.
- Ensure glue and scissors are used safely and with supervision as needed.