Investigate and compare the effects of pH on the catalytic effect of the enzyme catalase, found in (a) celery and (b) animal liver, on the rate of breakdown of hydrogen peroxide.
Investigate and compare how the solubilities, in water, of (a) potassium chloride and (b) sodium carbonate (anhydrous) change with temperature.
Investigate and compare how the rates of flow of powdered or granulated solids through a funnel are affected by (a) the size of the solid particles and (b) any one of the funnel dimensions.
You can find the practice reporting booklets for the set investigation titles here.
And, if you are planning on doing your own investigation, the practice booklet can be found here.