Water Potential Investigation
Planning the Investigation
I am going to find out whether the weight of potato cylinders increases or decreases when placed in strong and weak salt solutions and left for 48 hours, during these 48 hours the water molecules will diffuse from areas of high concentration to low concentration.
I predict that the stronger the salt solution, the lighter the potato cylinder will be after 48 hours.
I think this will happen because the salt solution has a very low water potential and the potato cylinder will have substantially higher water potential than the salt solution around it. As I will now explain, then water molecules diffuse from the potato cylinder to the salt solution; this makes the potato cylinder a great deal lighter as well. This is all due to high and low water potential. Water molecules move about rapidly from one location to another. The greater the concentration of water molecules in a system, the higher the so-called "water potential". The stronger the salt solution, the lower the water potential, and pure water has the highest water potential. When two systems containing water are in contact (in this case potato cylinder and salt solution), the random movement of the water molecules will result in the net movement of water molecules from the area of high water potential to the area of low water potential, until the concentration of water molecules in both areas, or systems is equal. This process is called diffusion, in water molecules move, according to the laws of energy, from region of higher to lower "free energy". This movement down gradients of free energy is diffusion.
Planning the Investigation
I am going to find out whether the weight of potato cylinders increases or decreases when placed in strong and weak salt solutions and left for 48 hours, during these 48 hours the water molecules will diffuse from areas of high concentration to low concentration.
I predict that the stronger the salt solution, the lighter the potato cylinder will be after 48 hours.
I think this will happen because the salt solution has a very low water potential and the potato cylinder will have substantially higher water potential than the salt solution around it. As I will now explain, then water molecules diffuse from the potato cylinder to the salt solution; this makes the potato cylinder a great deal lighter as well. This is all due to high and low water potential. Water molecules move about rapidly from one location to another. The greater the concentration of water molecules in a system, the higher the so-called "water potential". The stronger the salt solution, the lower the water potential, and pure water has the highest water potential. When two systems containing water are in contact (in this case potato cylinder and salt solution), the random movement of the water molecules will result in the net movement of water molecules from the area of high water potential to the area of low water potential, until the concentration of water molecules in both areas, or systems is equal. This process is called diffusion, in water molecules move, according to the laws of energy, from region of higher to lower "free energy". This movement down gradients of free energy is diffusion.
