SUBJECTS: Technologies
YEARS: 3–4
Have you seen large ships that carry shipping containers as cargo?
In this clip we show you how these ships use ballast to help them balance their load.
Find out what ballast is and how it stops a ship from sinking.
Also see the massive engines on these big cargo ships.
Things to think about
- 1.What types of things do cargo ships carry? Imagine how heavy the load is that they carry from one country to another. How do cargo ships that carry heavy loads avoid sinking?
- 2.What happens if the weight on board (load) is not balanced? How is sea water used to balance out the load? What is this sea water called? How do they know how much sea water is needed to balance the load? Where does the heat come from in the engine bay? Where do the engine's exhaust fumes go?
- 3.Draw a picture of a cargo ship with a heavy load. Show how ballast is used to balance the load. Draw the cargo ship again, showing the engines and where the exhaust fumes go. You may need to look at some other sources to find out more about how large ships work.
- 4.Use a 1-litre soft-drink bottle with a lid as your boat. Make and attach a sail and cabin. Test your boat in the water. You may find that it does not stay upright. Take it out of the water and add a small weight to the bottom of your boat, something heavy such as a metal bolt. Now test it again. This is like adding ballast to your boat. Why does it work?
Acknowledgements
Music by Glyn Lehmann.
Date of broadcast: 7 May 2001
Copyright
Metadata © Australian Broadcasting Corporation and Education Services Australia Ltd 2012 (except where otherwise indicated). Digital content © Australian Broadcasting Corporation (except where otherwise indicated). Video © Australian Broadcasting Corporation (except where otherwise indicated). All images copyright their respective owners. Text © Australian Broadcasting Corporation and Education Services Australia is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0).