Charles Law experiment

 When you heat a gas, it expands. This experiment aims to quantify this. We trapped a volume of air in a capillary tube underneath a small plug of conc sulphuric acid. You get the acid in by heating the tube and up ending it into the conc acid whilst still hot. As the air cools and contracts, it pulls the acid up. I think it is conc sulphuric to keep the air dry. We recorded the length of the air column as the temperature increased. You can just make out the sulphuric acid plug in the picture below.

We investigated a range of temperatures between 20 and 100 degrees Celsius, dictated by the water. Then we plotted a graph, extrapolating backwards to find where the volume of the air column would be zero. This occurs when the temperature is absolute zero. It's not an accurate experiment because we extrapolate backwards over 3 times the range of the readings.