Practice Biology Ia: Diffusion
Practice Internal Assessment Report
Christine Zhu
St Pauls Grammar School
00296648
Biology HL
Trial 1 & 2: 8/4/13
Trial 3 & 4: 10/4/13
Photo credits: Smarties by Andrew Dean, copyright Rebecca Douglas, retrieved 9/4/13 http://rebeccadouglas.photoshelter.com/image/I0000WDNZi_s2W4A
Smarties Diffusion Experiment
RESEARCH QUESTION
How does changing the colour of smarties affect the extent of its passive diffusion?
INTRODUCTION
Passive diffusion, also known as simple diffusion, is used to describe the exergonic reaction of a substance where the substance passes in the direction of the concentration gradient. Most of the molecules move from the area of high concentration, inside the membrane of a cell, to the outside where there is a lower concentration. No expenditure of energy is used during the transportation; the molecules are moved by their innate kinetic energy.
The purpose of the experiment was to model and investigate simple diffusion. This particular investigation was chosen because it is a simple demonstration of the processes of passive diffusion. The variables of concentration and spread are easy to work with; the experiment is also familiar because it has been conducted in year 7.
The concentration is an important factor in diffusion. It is expected that a bigger concentration will have a greater concentration gradient and thus more diffusion. In comparison, the smaller concentration will have a smaller gradient and hence less diffusion. Therefore, it is predicted that darker colours will spread better because of the more colour concentration.
RISK ASSESSMENT
Table 1 - Risk assessment and control measures Risk | Control Measures | Filter paper- flammable. | Do not expose to flame. After use, dispose of residue appropriately | Pipette Filler - possibility of ingestion of liquid if pipette filler is not used. Organic solvents may cause swelling of the surface layer of plastic, causing cracking. | Properly fitting pipette filler needs to be
Christine Zhu
St Pauls Grammar School
00296648
Biology HL
Trial 1 & 2: 8/4/13
Trial 3 & 4: 10/4/13
Photo credits: Smarties by Andrew Dean, copyright Rebecca Douglas, retrieved 9/4/13 http://rebeccadouglas.photoshelter.com/image/I0000WDNZi_s2W4A
Smarties Diffusion Experiment
RESEARCH QUESTION
How does changing the colour of smarties affect the extent of its passive diffusion?
INTRODUCTION
Passive diffusion, also known as simple diffusion, is used to describe the exergonic reaction of a substance where the substance passes in the direction of the concentration gradient. Most of the molecules move from the area of high concentration, inside the membrane of a cell, to the outside where there is a lower concentration. No expenditure of energy is used during the transportation; the molecules are moved by their innate kinetic energy.
The purpose of the experiment was to model and investigate simple diffusion. This particular investigation was chosen because it is a simple demonstration of the processes of passive diffusion. The variables of concentration and spread are easy to work with; the experiment is also familiar because it has been conducted in year 7.
The concentration is an important factor in diffusion. It is expected that a bigger concentration will have a greater concentration gradient and thus more diffusion. In comparison, the smaller concentration will have a smaller gradient and hence less diffusion. Therefore, it is predicted that darker colours will spread better because of the more colour concentration.
RISK ASSESSMENT
Table 1 - Risk assessment and control measures Risk | Control Measures | Filter paper- flammable. | Do not expose to flame. After use, dispose of residue appropriately | Pipette Filler - possibility of ingestion of liquid if pipette filler is not used. Organic solvents may cause swelling of the surface layer of plastic, causing cracking. | Properly fitting pipette filler needs to be
Bibliography: 9. Anonymous. (2009). Standard Deviation. http://standard-deviation.appspot.com/ 10 11. Anonymous. (last modified 2013). 68-95-99.7 rule. http://en.wikipedia.org/wiki/68-95-99.7_rule 12