Theme: Celebrate the Sea: Explore the deep

Seaweek '97 coordinator: Lin Fairlie

Extending the theme - classroom activities

The Depth Chart

Background

So far, exploration of the deep has reached about 4.5 kilometres, though exploration of much deeper regions has begun. The deepest regions of the sea are about 11 kilometres.

Aim

To gain some concept of the scale of the depth of the sea and the distribution of organisms in it.

Activity

• Find a piece of card or paper 2 metres long.
  
• Divide it into ten scaled 500 metre sections. The top section is above the ocean surface, it is for your heading and some sort of object to establish scale eg a bridge or ship. The other nine sections will take your chart to a depth of 4500 metres.
  
• Research the ocean. Mark where light ends (1000 metres) and draw in plants and animals, at the level in the ocean where they are found.

Adapted from the Primary Activity Booklet
in the Seaweek'97 Education Kit
by Jim Grant and Ann Fleming

Chat with a Scientist

Students can undertake a journal search but why not ask a scientist.

Activity

• Create a series of questions which can be answered by a panel of marine scientists on the internet at http://oceanlink.island.net/

• They ask for the user name in order to provide suitable information. For example: Are there any deepsea vents in Australian waters? How deep are the seamounts near Tasmania and what new marine life was discovered there?

Adapted from the Secondary Activity Booklet
in the Seaweek'97 Education Kit
by Jill Strachan

The Weight of Water

Background

Water is heavy. It is much, much heavier than air. The weight of water pressing down on the creatures deep in the sea is massive but they develop there and are not affected by it. They are drastically affected when hauled up to the surface and some parts of them explode as the pressure in their body is released. If a person was not protected by a submersible in the depths they would be crushed. We experience the pressure created by the weight of water ever day when we turn on the tap. The weight of water in the dam (which supplies us with tap water) pushes the water out under pressure.

Aim

To investigate the weight of water and the effects of pressure

Activity

• Fill a large bucket with 25 cm of water. What would be the weight of a column of water a metre high of a similar size? (just multiply by four). What would be the weight of water pressing down on a creature the size of the base of the bucket at a depth of 4, 000 metres (four kilometres)?
• If your school has very fine scientific scales you can compare the weight of air and water. Weigh an uninflated balloon and write down its exact weight.
• Now blow it up (but not too hard) then measure the circumference and weight it again. There should be a slight increase in weight. That increase is the weight of the air in the balloon.
• Now carefully fill another similar balloon with water until it has the same circumference. If it looks like bursting do not proceed. Weigh it carefully. How many times heavier is water than air?

Adapted from the Primary Activity Booklet
in the Seaweek'97 Education Kit
by Jim Grant and Ann Fleming

Further primary activities