NAME: YASODARA KARUNARATNE
CLASS: 12.4
SCHOOL: RENAISSANCE COLLEGE HONG KONG
September 2
010
IB DIPLOMA BIOLOGY [ IA TASK 2C ]
08
Fall
INTRODUCTION:
Surface areas to volume ratios are fundamental to biological processes such as gas exchange, absorption of nutrients and the excretion of waste. They affect how rapidly organisms lose or gain heat from the environments and they influence the rate of water loss from an organism by evaporation or transpiration in plants.
Plants adapted to dry habitats are known as Xerophytes such as cacti, which are, called succulents, as they are able to store water in specialized tissue.
[Taken form the task sheet]
AIM:
To investigate the relationship between surface area and the volume of a model cactus and to determine whether this relationship affects the percentage loss of water by evaporation. [Taken from task sheet]
METHOD:
1. Cut the oasis block into 2 blocks with an approximate size of 8cm x 8cm x 4cm.
2. Cut one oasis block into 4 cubes with approximate 4cm sides.
3. Cut the remaining oasis block into 32 cubes with approximate 2cm sides.
4. Weight all three sets of oasis blocks including the uncut one.
5. Put the three sets of blocks onto a tray and saturate them all with water.
6. Reweigh the blocks again and place onto a large tray by the window to allow for evaporation.
7. After 2-3 days reweigh the blocks and calculate the percentage water loss from each set of blocks.
8. Calculate the volume, surface area and the surface area to volume ratio for each set of blocks.
[Taken from task sheet]
APPARATUS:
* Oasis Blocks
* Scalpel
* Ruler
* Electronic Scale
* Tray
DATA COLLECTION:
| Block Set 1 | Block Set 2 | Block Set 3 |
DAY 1 | Length, Width and Height of Blocks (cm) 0.5mm | 8 x 8 x 4 | 4 x 4 x 4 | 2 x 2 x 2 |
| Original Weight of the set of blocks (g) 0.005g | 7.19 | 6.77 | 7.24 |
| Surface Area to Volume...