A student uses a pressure sensor to measure the total pressure at different depths in two open tanks. One tank contains water and the other tank contains cooking oil.
The Table shows the results.
Table
| Depth in cm\text{cm}cm | Total pressure in water in kPa\text{kPa}kPa | Total pressure in oil in kPa\text{kPa}kPa |
|---|---|---|
| 0 | 100.0 | 100.0 |
| 10 | 101.0 | 100.9 |
| 20 | 102.0 | 101.8 |
| 30 | 103.0 | 102.7 |
| 40 | 104.0 | 103.6 |
Explain why the pressure reading at a depth of 0 cm is not zero.
Describe how the total pressure in the water changes with depth.
Use data from the Table in your answer.
Give the pressure due to the water alone at a depth of 40 cm.
Deduce which liquid is denser.
Justify your answer using data from the Table.
On another day, atmospheric pressure is 98.0 kPa.
Predict the total pressure in the oil at a depth of 40 cm on that day.
132 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.