Floatation

 Investigate Parameters affecting Period or frequency of oscillation

IndependentDependantControlled MassPeriodFreshness of soda water Depth of Soda WaterFresh raisin TemperatureAtmosphere and Temperature Pressure

 Raisins  Electronic Balancing Scales  Knife  Board  Soda Water (13 bottles in the end)  Beakers  Thermometer  Hot plate  Video Recording Device  Stopwatch  Vacuum Pump  Conical Flask/Cork

 Carbon Dioxide is dissolved into water (Carbonation) to form carbonic acid  H 2 O(l) + CO 2 (g) H 2 CO 3 (aq)  The most CO 2 is dissolved at high pressures and low temperatures  Hence H 2 CO 3 is converted back faster to CO 2 at lower pressures and higher temperatures

Hence in our investigation we would investigate the effect temperature and pressure had on the system Mass and Water depth was tested to analyze the relationship the weight force of the raisin had with it’s buoyancy

 Parameters – Mass, Water Depth, Temperature, Pressure 1.Record the time, after 4 Minutes, that the raisin oscillates and reaches the top of the soda 2.With the recorded times calculate the differences between them and find the average. 3.Repeat each environment 3 times to ensure accuracy 4.Find the average of the three trials

 Average Period of each trial, and then the average of those three trials Mass (g)Water Depth (cm)Average length of Period (s) ± ± ± ±2

 Average Period of each trial, and then the average of those three trials Mass (g)Water Depth (cm)Average length of Period (s) ± ± ± ±2

 Average Period of each trial, and then the average of those three trials Mass (g)Water Depth (cm)Average length of Period (s) ± ± ± ±2

 1.At low water Depths, Mass does not have an observable effect  2.At higher Water Depths (8.5cm), Mass does have an effect  3.More bubbles would need to nucleate on heavier raisins to overcome the weight force, making the raisin boyant  4.In low water depths (low volume of soda water) the amount of carbonic acid being converted into CO2 was less so there would not often be sufficient bubbles to overcome the weight force of relatively heavy 1 gram raisin

Average Period of Three Trials: 7.16s±2

=22.5 degrees (Lab conditions) =60 degrees

 1.Temperature: As the Temperature increases the length of Period becomes shorter 2.Temperatures over 80 degrees too many bubbles formed and the raisin didn’t oscillate, hence there is a limit to the relationship at extreme temperatures 3.Also found over time because of the accelerated rate of Carbonic acid being converted to CO2, Bubbles run out faster than in a room temp. solution and hence after »3 minutes the bubble rate has decreased, hence increasing the period duration (not shown on graph)

Average Period of 3 Trials: 4.6s±1.5s

 1. The low pressure caused more bubbles to form giving the raisin more buoyancy to oppose the weight force  2. Limits existed in this experiment where pressure below 40 kPa would cause too many bubbles

 The Number of Bubbles are directly proportional to the period except at the limits where the raisin fails to oscillate (extremely low pressure and extreme high temperature)