IN THIS EXPERIMENT YOU WILL…
Conduct a series of 3 experiments. The first deals with the spontaneous movement of water trough tubes of various diameters. The second deals with the applied to water and the third looks at the pathway water takes to reach the source (leaf or flower). It is important when looking at the way it moves in a plant. It is also important to know the various ways in the plant substances move, as like with animal tissue, substances vary in the way they move from their point of absorption to where they are used.
MATERIALS
The box includes:
- Experiment booklet
- Digital software
- 100 ml glass beaker
- Capillary tube apparatus
- Water soluble dye x 2
- Retort stand and rod
- Retort clamp with bosshead
- Glass tube
- Pliers
- Small piece of Rubber tubing
- Wire
- Scalpel
- Paraffin in dropper bottle
- 250 ml glass beaker (250ml)
To be supplied by educator
- Water
- Potted plant
- Permanent marker
HOW DOES IT WORK?
In the 3 experiments the theory of how water move, is pulled through a plant and the pathway it takes was observed by students.
Experiment 1: The study of the spontaneous movement of water: Time allocation: 45 Min
The food colouring is added to water so that the movement of water is easily visible in the capillary tube apparatus. The water is then poured in the capillary tube apparatus. The capillary tube apparatus is a collection of tubes of various diameter on a stand. Water has a very distinctive “
” meaning its affiliation to spread it to relieve , this affects how it will move up the capillary tubes of different
. This is seen in the experiment.
Experiment 2: The study Root pressure in plants: Time allocation: 45 Min
The plant is cut off at the stem so that all the leaves and flowers are gone and only the
and roots remain in the soil. The glass tube is attached to the stem by using the rubber tube and wired so that it is water proof and sturdy; the glass tube is held up straight by the retort stand and clamp. When the water is added to the pipe, paraffin is added to prevent of the water from the tube, and the water level was marked. As the roots are watered, they apply
and “draw up” water from the soil, subsequently the water level will rise in the tube.
Experiment 3: The pathway of water through plant tissue Time allocation: 45 Min
The dye in the water allows us to track the movement of water in the stem and can be seen in the petals of the flower where it has stained the colour. When small
of the stem is viewed under the microscope the students can identify where the water moved through the stem.
PRECAUTIONS
- Use a sharp scalpel to cut the stem to ensure that xylem cells are not damaged.
- Add oil/paraffin over the water in the tube to prevent evaporation of water.
- The potted plant must be well water prior to the experiment
- The rubber tube must be airtight to Chemicals
- Paraffin First aid measures:
- Eye contact: Irrigate thoroughly with water. If discomfort persists obtain medical attention.
- Inhalation: Remove from exposure.
- Skin contact: Wash off thoroughly with soap and water.
- Ingestion: Wash out mouth thoroughly with water. In severe cases obtain medical attention.
- Spillage: Split material may lead to slippery surfaces.
- Firefighting measures: – Combustible if substance floats on surface of water. – Extinguish with foam, dry powder, carbon dioxide or vaporising liquids – Handling: Change contaminated clothing. Wash hands after working with substance.
Experiment 1: The Spontaneous movement of water: Capillarity
Time Allocation : 45min
AIM
To investigate the spontaneous movement of water through tubes with different diameters.
APPARATUS:
- 100 ml glass beaker
- Capillary tube apparatus
- Dye in dropper bottle
- Water
METHOD:
- Half fill the beaker with water.
- Add sufficient ink to dye the water and make it clearly visible.
- Observe the level of water.
- Place three capillary tubes of different diameters in the beaker.
- Observe the level of water in each capillary tube.
CONCLUSION:
Liquids have a natural tendency to move up tubes with narrow diameters (fine pores)
Experiment 2: Root Pressure
Time Allocation : 45Min
AIM
To investigate whether roots exert a pushing force strong enough to cause water to move up the stems of plants.
APPARATUS:
- Retort stand and rod
- Glass tube
- Pliers
- Small piece of Rubber tubing
- Wire
- Scalpel
- Retort clamp and boss head
- Paraffin in dropper bottle
- Pot Plant
- Water
- Permanent marker
METHOD:
- Carefully cut the stem of a well-watered plant about 4-5 cm above the soil level. (NOTE: use sharp scalpel so as not to damage xylem)
- Attach rubber tubing to the cut stem portion that remains.
- Tie the rubber tubing tightly to the glass tubing and the stem portion using pliers and wire.
- Clamp the glass tubing in the place using a retort stand.
- Add a little water through the open end of the glass tube.
- Add one or two drops of oil or Paraffin over the water in the tube.
- Mark the level of water and oil/paraffin.
- Continue to water the cut potted plant two to three times a day.
- Observe what happens to the level of the water in the glass tube.
RESULTS/OBSERVATION:
After a day or two, the level of water rises in the glass tube.
DISCUSSION:
Transpiration takes place through the stoma of mainly the leaves, and to some extend through, the stems. Since there were no leaves, transpiration could not have occurred and be responsible for the rise in water in the glass tube. The glass tube was not a capillary tube i.e. the bore is large not narrow to cause rise in water level in the tube. Therefore, the rise in water level in the glass tube could only be due to root pressure.
CONCLUSION:
Root Pressure is responsible for the upward movement in the plant.
Experiment 3: The pathway of water through a plant stem
Time Allocation : 45Min
AIM
To demonstrate the path way of water through a plant.
APPARATUS:
- Glass beaker (250ml)
- 15ml food colouring (preferably red or blue)
- Scalpel
- Water
- 2 white flowers
METHOD:
- Pour 200ml water into the glass and add 15ml food colouring.
- Cut 1 cm from the end of flower stem using the scalpel. Preferably keep the stalk under water while cutting.
- Immediately place the flower into the glass of coloured water.
- Place the glass in the direct sunlight and leave for 24 hours or a few days
- Notice the colour change to the white petals.
- Use a scalpel to cut a thin cross section. Make a wet mount and look at it under a light microscope.
CONCLUSION:
In the 3 experiments the theory of how water move, is pulled through a plant and the pathway it Takes was observed by students.
Add Comment