Task description: ERT on gases You have studied the gas laws during lessons. You have to respond to the following tasks in an assignment format: • Your response must be 1000 to 1500 words excluding tables, graphs, formulas and calculations.

• You will have some time in class to do this, but you must also use home time to complete your assignment. • Your work must be done individually.

• You will have the opportunity to submit a draft for feedback from your teacher. Task 1

Josh and Jack dive from a boat to a depth of 30 m in the ocean near the Gold Coast. Josh is a free or 'skin' diver and holds his breath while Jack is a scuba diver and breathes compressed air from a tank. They both descend to a depth of 30 m.

Task 1a Your task is to perform appropriate calculations and construct graphs that shows how each of the following variables behaves as a function of depth: • Total pressure (in kPa) acting on the divers' bodies • The volume (in L) of the gas in each diver's lungs

• The amount of air (in mmol) in each diver's lungs. You have to plot both Josh's and Jack's information on each of your graphs so you can compare them.

You have to show the calculations for at least one depth so the method you used is evident. The rest of your table can then be completed. For each graph:

• Systematically analyse your primary and secondary data to identify the trends and the relationship between them. • Describe each trend with a mathematical relationship and in words. Include appropriate reasoning and calculations to justify your mathematical relationships. • Compare and explain the trends found for Josh and Jack.

Assumptions made for the purpose of this question:

• Each diver's lung capacity is 6 L at the surface. • Both divers' lungs contain the same number of air particles prior to descent. • Each pair of lungs behaves like balloons. • Ignore any biological gas exchange that may take place in the lungs during the dive.

• Assume the water and body temperatures remain the same. Task 1b

Plot a graph to show the relationship between the total pressure and the volume of the gas in Josh's lungs. • Identify the trend of the graph and the relationship between pressure and volume.

• Evaluate the scientific interrelationships and the validity of your findings under extreme pressure. Task 2

Deep sea divers sometimes experience decompression sickness, more commonly known as 'The Bends' if they do not return to the surface slowly. Your task is to scientifically explain why this happens.

To complete this task successfully, you have to: • Provide a short reproduction and interpretation of the condition and technical information such as the composition of air and blood, appropriate formulas and laws. • Explore suitable scenarios and make appropriate and justified assumptions.

• Perform appropriate calculations to aid in the justification of the physiological effects of The Bends. • Include appropriate graphs to use in the identification and explanation of scientific relationships.

• Use scientific reasoning to make justified suggestions on how to treat patients that suffer from The Bends.