The Science of a Historic Sinking

After more than a century, the fascination of the Titanic’s maiden voyage and sinking remains. With artifacts being exhibited around the country, the blockbuster movie rereleased in 3D, and a Titanic II being built with a scheduled maiden voyage planned for 2016, the story still slakes our thirst for romance and tragedy. When you add the ghostly images from the North Atlantic and man’s ability to reclaim treasure from the seafloor, the Titanic’s magnetizing effect seems nearly unbreakable. As a story from history, Titanic will capture your students’ interest. However, to maximize the time spent on the topic, consider a few science investigations to explore another facet of this tragedy. 

How the Titanic was Different

The original reason for billing the ship as unsinkable came from the design of its watertight compartments. Three compartments could fill with water, but the ship could remain afloat. To demonstrate this, have pupils collect empty milk cartons from the cafeteria. Each model ship will require six empty cartons:

• Seal each milk carton shut.
• Bind the six sealed cartons together with hot glue in a three-by-two array. It would be helpful to make 3 models for a total of 18 cartons.
• Now make a fourth, slightly different model from a quart-sized milk carton and seal it with hot glue like the others.
• Attach a shoe box lid to the the top of each of the four models.
• Let the kids add people, furniture, and props to heighten the drama when the boat sinks.

Discussion Question:

• What are the differences in the two unique designs? (One large compartment versus several, smaller watertight compartments)
• How might these differences affect sinking?

Cut a hole in the quart model and a hole in one carton of multi-carton ship model. Record the time they take to fill with water. Repeat with the other ships, but cut holes in two of the cartons on ship two, and cut holes in three of the cartons on the third model. Will adding more watertight compartments change the outcome? Titanic actually had sixteen compartments. If time allows, let kids experiment to see if they can recreate Titanic’s three-hour sinking.

The Role of Water Pressure

Children may wonder how an unsinkable ship could slip below the water in such a short time (about three hours). One way to demonstrate the effect of water pressure on sinking time is to use a five-gallon bucket. Before class, punch three holes in the bucket with a hammer and a thick nail, or screwdriver. One hole should be one inch from the bottom of the bucket. This hole represents twenty feet below sea level which is the depth at which the iceberg punctured the hull. Punch the other two holes at five inches and nine inches. Cover the holes with strong tape.

Students should predict what will happen when the tape is removed:

• Will water stay in the bucket?
• Will it shoot an equal distance from all the holes?

It may be best to take this experiment outside due to the volume of water. Otherwise, you will need to have a large sink or basin handy. It’s important that the bucket be elevated a few feet off the ground. Fill it using either a second five-gallon bucket or a hose. Explain to students that the bucket of water represents the ocean and the rest of the room is the ship. The holes represent the punctures made into Titanic’s hull so they are actually observing the water as it rushed into the ship. Remove the tape and observe. How do they think water pressure affected the sinking time?

To Rust or Not to Rust

Even before the doomed ship reached the ocean bottom, salt water was working to degrade the ship’s hull. Titanic sat in ocean water for a full year before it set sail, which some believe weakened the type of rivets used to hold her together. Your class can explore how salt water weakens different types of metals.

An empty fish aquarium works well for this investigation, but a clean bucket will do. You will need the following supplies:

• Kosher salt.
• Iron nails.
• Equal lengths of copper, galvanized steel, and aluminum wire.

For each gallon of water, add 4.5 ounces of salt, about a half cup. As an extension, you can also set up another investigation with fresh water.

Wrap the wires around glass-stirring rods, leaving several inches hanging off. Repeat using the nails in place of the rods; lower them into the water. Each day, remove the wires and have pupils tug firmly to check for weakening. Observe any other changes. Is there any difference between the wires wrapped around the rods versus the nails? What might this represent? Note: Titanic’s hull was made of a different kind of metal than the rivets used to hold the hull plates together. Metals give up their electrons at different rates in a process called galvanic exchange. Secondary students can add this to their investigation.

For most, the tragedy of Titanic’s sinking is a historic human interest story. For scientists, it offers countless opportunities in scientific investigation.

Visit Lesson Planet for More Ideas about Titanic’s Voyage and Sinking:

Six Ways to Teach about the Titanic Disaster

This article suggests cross curricular ideas to study the Titanic from multiple angles. Research skills are emphasized as well as data analysis and writing. Most activities can be adapted for fourth grade and up.

What’s Eating Titanic?

This lesson for secondary learners focuses on biodeterioration processes below the sea surface. It focuses on the effect of rust-eating microbes found in the ship’s remains and applications for the knowledge that scientists are gleaning it.

Titanic Tales

An in-depth resource from Texas Instruments requires the use of calculators and familiarity with the function keys. Activities focus on reading and interpreting graphs and charts and making comparisons between data sets. Pupils also determine whether the data is misleading.