Boating with KidsApr 12, 2022
For kids, boating can bring such pleasure. Boats in the bath. Boats in the pool, the creek, lakes, rivers… So many different shapes and sizes. From boats to ships. Watching ships transporting cargo as they leave for far away ports, going from country to country. People holidaying on yachts and cruise liners. Kids’ curiosity is piqued. How do boats and huge heavy ships float?
For some kids, however, boats have served a different purpose, as a means of rescue. The floods along the east coast of Australia have been devastating.
Our creeks, rivers and lakes are impacted by our weather. Droughts and lack of water are commonplace in our dry outback. But flooding from torrential rains can be just as devastating. Movement across water takes on a new meaning: boats to rescue people, animals and possessions; and connecting one place to another.
These waters can be treacherous and boats tend to be motorised for easier control and manoeuvrability. The design and use of technologies have come a long way since the reed boats built by the Egyptians about 4000 BC.
Often the early experiences for kids with boats are toy versions perhaps a plastic bathtub tug. But the best can be the boats that kids make themselves, like Winnie the Pooh, in the book by A A Milne. His stick-like boats dropped from a bridge have created entertainment for generations - Pooh Sticks. This game is simple. Kids each drop a stick off one side of a bridge over moving water. The first stick to appear on the other side of the bridge is the winner.
Autumn is a great time to try floating the beautifully coloured leaves that have fallen from trees, down a creek or even down the gutters lining the side of a street - once flood waters subside. Or pieces of bark with little gum nuts on top as crew! How many can fit? Can you float a stone on a piece of bark down the creek?
This type of play can be enlightening and educational for kids. Questions start to emerge. Why do some things float and others don’t?
For middle primary levels, Years 3 & 4, the Australian Curriculum: Design and Technologies looks at how forces and the properties of materials affect the behaviour of a product. Students identify and explore the construction of an engineered product, like boats and ships. Considerations relate to the weight, mass, density and volume of an object. This YouTube clip explains the concept of buoyancy and flotation: What makes something Float or Sink?
If you are working with older students, this video may be useful: Why do big ships float?
A simple way to look at these concepts:
- Mass is the amount of stuff inside an object. (eg measured in grams)
- That object takes up a certain amount of space - its volume. (eg cubic metres)
- Density is how much mass there is within the space or volume of that object. (eg grams per cubic metre)
- Weight is gravity acting on the mass. With no gravity there is no weight.
Archimedes was a Greek scientist and inventor. He came up with this principle while having a bath. Kids can try this too! Watch the level of the water rise when they get in. This is displacement.
“Any object, totally or partially immersed in a fluid or liquid, is buoyed up by a force equal to the weight of the fluid displaced by the object.”
So when any boat displaces a weight of water equal to its own weight, it floats. Example on a massive scale: a 10,000-ton ship's hull must be built wide enough, long enough and deep enough to displace 10,000 tons of water and still have some hull above the water to prevent it from sinking. The shape and structure can alter its density.
Practical experiments can be a good place to start:
- Try a simple version of the one shown in the video clip with a ball and a boat both made from modelling clay and weighing the same. However, by changing the ball to a cup shape, the density has changed.
- Another option is to collect a variety of food packaging like foil or plastic trays. In a sink or bath of water try adding different objects, light and heavy, to see how this affects the flotation of the tray.
- Consider the volume of each tray and how much mass it can hold
- Consider how to design a boat that traps air so that it can potentially hold more…
- Or construct your own boats from foil. Experiment with shapes and sizes.
More questions. What’s the difference between a boat and a ship?
The difference basically is to do with size. A ship can carry a boat but a boat cannot carry a ship. The purpose of a ship is often to carry cargo / passengers across oceans. Ships use far more complicated navigation systems. They require a captain and trained navigators and engineers as crew. Ships can have huge ballast tanks which can be full of air or can have water pumped in and out to help balance the ship’s load, and adjust the density.
History of boats and ships
The Egyptians made reed boats adding sails. Galley’s were sailing boats powered by men with huge oars. The Vikings created longboats also powered by men on oars which could go on rivers as well as the sea. The Chinese had junks with a rudder for steering and battens on the sails to make them stronger. Then, later sailing ships had 3 or 4 masts, and were used in battle as well as for exploring and transportation.
In the early 1800s steam power supported the power of the wind in the sails and ships took passengers to the newly discovered worlds. By the mid 1800s ships were being built with iron and used a propeller instead of sails to create movement. In the late 1800s paddle boats navigated the calmer waters of rivers.
As technologies changed with new discoveries in the early 1900s, burning coal for power was replaced by diesel, and oil provided the power rather than steam. The design of ships changed depending on the purpose with big, wide, flat cargo ships transporting containers, and multi layered cruise ships carrying passengers.
So, boats and ships have come a long way. We all have vastly different experiences with boats and ships: some pleasant memories, some that have not been such a happy part of our journeys, some kids with no experiences at all. I want to encourage our children to think about boats creatively and with curiosity, to draw on happy experiences or create new ones.
Coming back to kids and boating… and ART. There are many many different shapes and sizes of boats. Whether just drawing for fun or creating a sketch for your own boat design, Artventure has some starting points. Try searching for 'boats' and these lessons: Speed Boat, Sailing boat, Shapes and patterns landscape, Pelican, First fleet ship, Summer.
Maybe students can draw a diagram that illustrates how a boat floats. See if your children can explain this to someone else. If you have a boat, or know someone who has, have a close look at its design and construction. Boat building has changed dramatically over time but behind all built structures is a design, a drawing. Art and design go hand in hand. Science and Technology then come on board. Create a design brief for the kids to develop their ideal or imaginary boat or a boat that would best suit their situation and needs. What about a variation of an amphibious boat??
Help them to float an idea! Let’s encourage the designers and inventors of tomorrow to build their dreams.
Teacher and Artventure Blogger