potometer

Question 1

what does a potometer measure

Answer 1

measures water uptake in plant, rate of transpiration

Question 2

factors effecting

Answer 2

temp
humidity
wind
light
water availability
SA

Question 3

why should the plant be cut under water

Answer 3

prevent air bubbles

Question 4

why is it cut at a slant

Answer 4

to increase SA for more water uptake

Question 5

control variables

Answer 5

light
wind
humidity

Question 6

how do u control light

Answer 6

change distance between lamp and potometer

Question 7

how do u control wind

Answer 7

using a fan at different speeds

Question 8

how do you control humidity

Answer 8

wrapping a plant with plastic bag

Question 9

limitations of this

Answer 9

not all water is transpired some is used for photosynthesis

when plant is cut the plant starts to die so uptake is lower than normal

Question 10

how is rate of transpiration calculated

Answer 10

-measure distance bubble traveled in the capillary
-measure the radius of capillary
-find the volume of water taken up by using pi x r^2
-divide volume by time

Question 11

outline the procedure

Answer 11

1. set up the potometer
2. clamp the capillary tube into the stand. place the bottom of the capillary tube into the beaker of water
3. smear petroleum jelly around the joint to maintain airtight conditions
4. leave for 5 mins for a bubble to be drawn into capillary tube
5. measure the movement of the bubble along the capillary tube in a certain length of time
6. repeat the experiment and change abiotic variable