I reject my hypothesis. I reject my hypothesis because I thought that nothing will happen to onion if we add saltwater, pure water and vinegar water but that didn’t happened. An onion is a multicellular (consisting of many cells) plant organism. As in all plant cells, the cell of an onion peel consists of a cytoplasm, nucleus and a large vacuole, cell wall and cell membrane which is selective permeability. Water moves from a high concentration of solutes to a low concentration to make a balance between the salinity of the water inside the cell and the water outside of the cell and that was why my hypothesis was wrong when water or salt in water was greater outside the cell than inside, high concentration move to low concentration that process will happen until inside and outside be equal and that’s called osmosis which is special type of diffusion that involve water molecule. Osmosis is the special case of diffusion involving water molecules. Water molecules move from areas of high water concentration to areas of low water concentration through a selectively permeable membrane. I learned so much from this experiment for example diffusion, permeability and osmosis. Also i learned that if i hold coverslip at 45 degree angle it will prevent from air bubbles and that I need 23%(dissolving 15 ml of table salt (NaCl) in 50 ml of water or 15 ml Nacl in 50 ml of water) of NaCl for this kind of experiments. Also I learned osmosis when i added saltwater to onion, the onion cells lost their own water and disperse it into the surrounding salt water due to osmosis (osmosis is the movement of water through a selectively permeable membrane). Osmosis is diffusion of water across a semipermeable membrane. Semipermeable membrane is a thin barrier between two solutions that permits only certain components of the solutions, usually the solvent, to pass through. Salt is too big to pass through a cell membrane, but water molecules can fit. Since everything want reach equilibrium, the only thing that can flow to create equal concentration(The quantity of solute (for example sugar) dissolved in a given volume of solution (for example water) is water. When pure water added to onion, the onion cells absorb the pure water around them because the waters inside the onion cells naturally have a small amount of salt. Basically osmosis make all the water involved equal according to how much salt is in there. Also vinegar water which is acid and because of its acid it broke down cell wall of onion cell. This could also break down entire cell too and that’s why cell appear black hole.  Osmosis and diffusion happen lot in everyday life. For example diffusion happen in plant when a leaf cell is photosynthesising the concentration of carbon dioxide outside the cell is greater than the concentration inside, so carbon dioxide diffuses into the cell. But the concentration of oxygen inside the cell is greater than the concentration inside, so oxygen diffuses out of the cell. Also osmosis happen to plant when root hairs of the plant take in water from soil and because the vacuole is low concentration and water in soil is high concentration water passes from the soil into root hair cell. So now vacuole is high concentration of water. Water will now pass from this are of high concentration to the next cell which has low water concentration. So water continues to move along the cells of the root up the xylem to the leaf. That means all the time water is moving to areas of  lower water concentration.

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