A student is investigating how the boiling point of a salt solution varies with pressure. It is suggested that the relationship between the Celsius temperature θ at which the water of the solution starts to boil and the air pressure P is θ = kσP^q where σ is the density of the solution and k and q are constants. Design a laboratory experiment to test the relationship between θ and P. Explain how your results could be used to determine values for k and q. You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to • the procedure to be followed, • the measurements to be taken, • the control of variables, • the analysis of the data, • any safety precautions to be taken.