Introduction: Agar is a polymer made up of subunits of the sugar galactose, its also a part of the cell walls of several species of red algae that are found in eastern Asia and California. Agar is dissolved in boiling water and cooled, because of this laboratory agar looks gelatinous. Other less well-known uses include serving as a thickening for soups and sauces, in jellies and ice cream, in cosmetics and for clarifying beverages. Agar is used for culturing bacteria, its more beneficial than regular jello because it wont be eaten by bacteria and Agar is more stronger and firmer.
Diffusion is one of the most important processes that happens in a cell because it is used to transport matter like molecules, nutrients, water, oxygen, and cellular waste through the cell membrane. In the
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The students then place the cut and measured Agar cubes in 3 separate beakers of the NaOH at the same exact time.
A timer is used to keep track of the time and the Agar cubes must stay in the beaker for 8 minutes.
Once the eight minutes are done the students must remove the Agar cubes and place them on a cutting board and cut into it using the scalpel.
Once cut, they can measure the rate of diffusion by using a ruler.
Repeat the steps again for the measurements of 3 cm3 but use 60mL of NaOH, and for the 5 cm3 the students must use 80 mL of the NaOH.
Risk Assessment:
The risk assessment in this lab revolves around lab safety. The students must be wearing their gloves and aprons at all time to be careful with the Agar and to not spill the NaOH on their school uniforms. Also while cutting the Agar Cubes they must carefully and cautiously avoid directing the scalpel towards their fingers or wave the scalpel around in the direction of their classmates. If the Agar is not measured correctly this could leave a huge flaw in the
Next prepare the third test tube with an accurate measurement of 5ml sodium carbonate once again labelling appropriately.
1. Gathered all required materials to designated lab bench. 2. Considered all safety precautions including the prevention of spilling water to avoid falls, handling glassware carefully to prevent shattering, avoiding long periods of working with warm water to avoid burns and avoiding the digestion/inhalation of by-products produced after the reaction (e.g. ethanol and carbon dioxide gas). 3.
First, we added water to the graduated cylinder to 20 mL. Then, placed the unknown substance in the water, the water increased and measured 25 mL. The volume was determined by subtracting 20 mL from 25 mL. The volume equaled 5 mL for the unknown substance. Next, we filled the water to 20 mL in the graduated cylinder. Then, placed aluminum in the water, the water increased and measured 25 mL. The volume was determined by subtracting 20 mL from 25 mL. The volume equaled 5 mL for aluminum. After that, we added water to the graduated cylinder to 20 mL. Then, placed the zinc in the water, the water increased and measured 22.5 mL. The volume was determined by subtracting 20 mL from 22.5 mL. The volume equaled 2.5 mL for zinc. Last, we added water to the graduated cylinder to 20 mL. Then, placed lead in the water, the water increased and measured 24 mL. The volume was determined by subtracting 20 mL from 24 mL. The volume equaled 4 mL for
1) Separate the solid from the liquid in the beaker by decanting the liquid. Ask your instructor to demonstrate the correct procedure.
I started with controlling my experiment environment. It was in a still kitchen, with no appliances running to minimize humidity and control the room temperature. I then broke my ice cube tray and finding cubes that weight .10grams. I set up my timer for each station. I put three-.10gram ice cubes in a identical contained on top of the pre measured ½ teaspoon of sugar, salt and baking soda, then I hit start on the timer. When the timer hit 15 minutes I picked up each ice cube and put it on another dry identical dish. I then measured the melted liquid, followed by measuring the melted ice cube alone. I repeated this three times to get an average.
* Record how long it takes for each Ice Cube to melt completely, taking progress notes as you go. For instance, the percentage of the ice cube that has melted at 5 minutes, 20 minutes, etc.
The purpose of this lab was for the student to get involved with his or hers new lab kit as well as being able to know, identify and use each other tools provided in the kit. Another key learning aspect of this lab is to teach the student how to measure properly the many units in the SI system. I will be using laboratory dilutions, measurements, and weights to then calculate using algebraic formula.
A 100 mL graduated cylinder should be used to measure out ~40 mL of water.
With the other two trials were 0.18g, for the second trial and 0.17g for the third trail for Mass of Sodium Acetate After 3 ½ Minutes (g). These results demonstrated that the first trial had the most sodium acetate in it and it had more time to react with the oxygen in the air. Errors were involved with the first beaker being weighed. The beaker needed to cool down for more than 1 min ensuring that the plastic balance was no get damaged. In a 30 second of planning out a new time limit which was 3 and a half minutes.
All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The process in which molecules of a substance move from an area of high concentration to areas of low concentration is called Diffusion. Whereas Osmosis is the process in which water crosses membranes from regions of high water concentration to areas with low water concentration. While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help.
Cells are always in motion, energy of motion known as kinetic energy. This kinetic energy causes the membranes in motion to bump into each other, causing the membranes to move in another direction – a direction from a higher concentration of the solution to a lower one. Membranes moving around leads to diffusion and osmosis. Diffusion is the random movement of molecules from an area of higher concentration to an area of lower concentration, until they are equally distributed (Mader & Windelspecht, 2012, p. 50). Cells have a plasma membrane that separates the internal cell from the exterior environment. The plasma membrane is selectively permeable which allows certain solvents to pass through
|EMB Agar | |Distinguishes bacteria that ferment |Dark blue colonies with|E. coli and P. |
diffusion is one of the passive transport processes. it is used in oxygen entering a cell and carbon dioxide leaving a cell. diffusion is the movement of particles such as atoms or molecules from a high concentration place in an area of a low concentration. this shows that they diffuse down the concentration gradient. the concentration gradient is a gradual change in the concentration of solutes in a solution as a function of distance through a solution. in biology a gradient results from an unequal distribution of particles across the cell membrane. When this happens solutes move along the concentration gradient until the concentration of the
Measure 500ml of tap water in the 500cm3 beaker, then measure 5g of sodium hydrogen carbonate using the 50cm3 beaker and weight scale and place in the beaker of water, using the glass rod to dissolve it into the mixture.
Diffusion is an automated process by where the levels of oxygen, water and carbon dioxide pass over a ‘semi-permeable membrane’ between the walls of the cells and blood vessels to create a level environment. This membrane only allows these three elements to pass whilst retaining other elements such as blood cells, hence semi-permeable. The high concentration on one side of the cells transfers through this membrane until the level is equal on both sides.