This is the final design of our t-shirt! Please pay up RM25 asap to SiWen (treasurer) The sooner you pay, the sooner we will get it. We'll wear it during Canteen Day!
<3 peifen
Friday, February 12, 2010
hey guys.. so sorry about that link part.. idk why it wont enter the spaces.. i cant make the font smaller. anyone who knows, do it ya. hope you guys like the new template.
Aim : To study the effect of air movement on the rate of transpiration using bubbles potometer.
Problem statement : How does the movement of air affect the rate of transpiration?
Hypothesis : The faster the movement of air, the greater the rate of transpiration.
Variables :
Manipulated : Air movement.
Responding : The distance travelled by the air bubble in 5 minutes.
Constant : Surrounding temperature, type of plant, light intensity.
Materials : A leafy shoot, vaseline, a piece of cloth and dilute eosin solution.
Apparatus : A rubber tubing (5cm), a capillary tube (40cm), a 250ml beaker, secateurs, a retort stand, a stopwatch, a stopwatch, a ruler and a basin of water.
Technique : Measure the distance travelled by an air bubble in a potometer in 5 minutes using a ruler.
A bubble potometer.
Procedure :
1.A leafy shoot is chosen from a plant. The shoot with secateurs is cut off and the cut end is immersed immediately into a basin of water.
2.About 1cm of the stem is cut obliquely under the water from the cut end of the shoot.
3.The rubber tubing is fix into the capillary tube under the water. The rubber tubing and capillary tube is filled with water. The air bubbles are make sure not trapped inside the capillary tube.
4.The stem is fix to the rubber tubing under the water. The leaves are make sure kept out of the water as much as possible.
5.The apparatus are removed from the water and set up as shown in the figure above.
6.The end of the capillary tube is immersed in a beaker of water.
7.The leaves and apparatus are wiped dry with dry cloth.
8.The joint between the stem and the potometer are smeared with Vaseline to prevent leakage of water and the apparatus are airtight.
9.The capillary tube are removed from the beaker and the rubber tubing are pressed to remove a drop of water from the capillary tube. A bubble of air are allowed to enter and the capillary tube are placed back into the beaker.
10.The potometer is placed in an enclosed room with no air movement.
11.A few minutes are allowed for the shoot to reach a steady state before taking any readings.
12.The stopwatch is started and the distance travelled by the air bubble in 5 minutes is recorded.
13.Repeat steps 11 and 12 by placing the potometer under fast moving fan.
14.The distance travelled by the air bubble under both conditions are recorded in the following table.
Precaution steps :
1.When you select the shoot, make sure the base of the shoot fits snugly into the stopper or rubber tubing of the potometer.
2.Choose a shoot with many leaves as the shoots with few leaves often give inadequate results.
3.Do not allow the air bubble to reach the end of the shoot.
Results :
Condition
Distance travelled by the air bubble in 5 minutes (cm)
Rate of transpiration (cm/minute)
1st reading
2nd reading
3rd reading
Average
Non-windy (still air)
0.30
0.25
0.20
0.25
0.050
Windy (fast moving fan)
0.30
0.50
0.20
0.33
0.066
(maybe you all couldn't see the title)
Graph of rate of transpiration against condition
Discussion :
The leafy shoot must be cut under water to prevent air bubbles from forming inside the xylem vessels of the shoot. This ensures a continuous column of water inside the xylem vessels. The connection between the stem and the potometer is smeared with Vaseline so that the potometer airtight and no bubbles are formed inside the potometer.
The movement of the air bubble in the potometer indicates that transpiration is taking place. The potometer measures the rate of water uptake by an isolated leafy shoot. The rate of water uptake by a detached shoot is the rate of water evaporation from the leaves and stem into the atmosphere. Therefore, a potometer indirectly measures the rate of transpiration. In a potometer, the water in the xylem vessels in the shoot is continuous with the water filling the capillary tube that reaches the cut end of the stem.
From the graph, the movement of the air bubble in the potometer is placed under a fast moving fan represents the process of transpiration in an environment with high wind velocity. The rate of transpiration is higher when there is air movement (the potometer under a moving fan). The faster air movement helps to remove the water vapour which diffuses from the stomata and accumulates near the leaves surface.
The assumption made in this experiment is that the potometer measures the rate of transpiration because it is the same as the rate of water uptake by the shoot. The distance travelled by the air bubble in the given time gives the rate of water uptake by the plant. This is the indirect measurement of the rate of transpiration.
Conclusion :
The faster the movement of air, the greater the rate of transpiration. The hypothesis is accepted.
Homework During Chinese New Year :
BM - Karangan - Surat Rasmi (aduan), Laporan Aktiviti, Wawancara Tokoh
Math - Waja, Activity Book (chap 3-5)
Add Math - Waja (chap 1-3)
Chemistry - Text Book (exercise)
Biology - PEKA (above)
Moral - Folio, Work book (unit 5-9), Esei (unit 5&6)
2010 will be another though year, loaded with never-ending homework.
SPM year girls!! Gotta work hard!!
And all of you... Please don't ponteng latihan rumah sukan.. Esp those rafflesians hahahaha...
I know.. lame. =P Do you know what is lame?? THIS is:
Lim Pei Fen[LAME POST] Couldn't do any homework due to the absence of correction tape. (Yes.. I haven't solve that) Went to Chiew to get one but couldn't find the one I wanted thus bought a liquid paper instead. Para pengawas sekalian jangan rampas ya... =D
My status yesterday =P Dah buat homework sampai satu wayar dah putus. GOOD...that is gooooodd... xD
its 2010 already and 4 physics has *eherm* matured into 5 Physics5 Bestari.
Sad to say. this blog is dead!!!!!!
people people!
update the blog girls!!!
*sings* update update update!!!!
zz okie, i sound dumb.
back to topic, its 2010 already and some of us are still writing 2009/4 Physics on our exercise books.
Homework piles up like a mountain as usual and we have some new teachers! :)
Bm- Puan Rosnah
English-Puan Fauziah
Math-Puan Khatijah
Sej-Puan Ramlah
Moral-Puan Liyana
Add Math- Miss Tang
Chem-Cik Ilyanie
Physics-Puan Saidatul
Bio-Cik Balkis
everyone is busy busy as usual.. including me, so I'll sign out for now.
hopefully, the blog will be updated the next time I come in!
Toodles!
Our class blog is like DEAD. Can someone please just update it? Oh ya, school is reopen soon. No longer, we have to wake up early in the morning. The most important thing is, make sure you've completed all your homework. :)
Bm - 6 essays, synopsis of Julia Bi - 3 essays Math - one set of paper Add Math - a few sets of paper, analysis for Form4 exams Physics - notes Chemistry - notes Biology - scrapbook, peka Moral - notes Civics - 1 essay
