LAB REPORT 2

Topics: Osmosis, Diffusion, Semipermeable membrane Pages: 7 (1355 words) Published: November 19, 2014
FUNDAMENTALS AND CONCEPTS IN BIOLOGY 1
LAB REPORT TWO (2)
Renuka Ramtahal
00044355

TITLE: An examination of diffusion rates of solutes.
INTRODUCTION: Diffusion is the movements of particles or molecules along a concentration gradient or from a region of higher to regions of lower concentration until it is evenly distributed throughout the area (until there is equilibrium). The simplest means by which solutes enter and leave a cell is via diffusion. Diffusion occurs in gaseous state or within gas molecules and liquid molecules. The effects of temperature on rate of diffusion will be observed. AIM: The observation of the effects of temperature on rate of diffusion. OBJECTIVES: Observing diffusion at different temperatures (Ambient, cold and hot) through the use of filter paper and potassium permanganate. STATEMENT OF EXPECTATIONS: We know that chemical reaction speeds up with temperature, and that the potassium permanganate will expedite at high temperature. Therefore we expect that the rate of diffusion of the potassium permanganate to be greatest at the highest temperature. METHOD:

Three (3) test tubes were labelled with our group name and “hot”, “cold” and “ambient”. A disc of filter paper was saturated completely in a concentrated solution of potassium permanganate (KMnO4). For each of the nine (9) test tubes the disc was quickly dunked into a beaker filled with distilled water to wash of excess dye and then placed at the bottom of the test tubes. Ten (10) ml of water was quickly poured into each test tube using a syringe gently introducing the water (H2O) to the test tube by aiming the flow of the water (H2O) down the side of the test tubes. The test tubes were immediately transferred to the appropriate incubation chamber, the water (H2O) bath at 60 °C, the ice bath and the water bath at ambient temperature. Each of the incubation chamber the temperature was measured. The test tubes was removed from the incubation chamber after ten (10) minutes and dried with a paper towel ensuring that the content was not agitated. Each test tube was held in turn against the scale that I drew and how far the dye travelled in the water column was measured. RESULTS:

TEMPERATURE

SARAH
PADRAJ
THUNDER CATS
LOL
RITE
X
SD
21°C
426
271
326
103
335
292.2
119.5
4 °C
1201
373
471
332
682
611.8
356.09
60 °C
170
23
22
84
85
76.8
60.62

V= Sum of squares of variance from mean
= (247-426)2 + (247-335)2 + (247-271)2 + (247-326)2
SD=√ v.

Temperature affects the rate of diffusion an as seen from the results at 60 °C hot water the rate of diffusion was the fastest whereas at 4 °C cold water the rate of diffusion took the slowest to occur. The group LOL ambient temperature was faster compare to the other groups and the group Sarah at 60 °C the rate of diffusion took longer.

DISCUSSION: As temperature increase the rate of diffusion increases. In the experiment as temperature increase so did diffusion and this trend was seen because at normal temperature particles are passive (no energy added) however when the temperature increase there were kinetic energy added so the particles move faster. The test tubes were placed in test tube holders so they won’t fall and break. The students were to be careful around the hot plate so they won’t burn their hands. Lab coat was worn so if anything spill it will protect you.The rate of diffusion was timed using a stop clock a source of error could be that the student stop the clock before diffusion reach end point or the student wasn’t paying attention and stop the clock after end point. The temperature of the incubator could not have been tested before placing the test tubes in it.Apparatus and material should have been set up and ready for the experiment to be carried out.

TITLE: Effects of osmosis on portions of root tuber tissue.
INTRODUCTION: Osmosis is the movement of water molecules or particles through a semi-permeable membrane from an area...
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