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Plant vessels

Add food colouring to a petal of a white flower, and see the path water takes through the plant.
Science content (2016 curriculum): 
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
Biology: Classification of Living Things, Biodiversity (1, 3)
Biology: Sensing, Organ Systems (4, 5, 6)
  • white petal - a carnation works well
  • tape
  • clear plexi or other stand to tape petal to
  • wax paper
  • food colouring

Plants need food molecules to stay alive, just like we do. Plants move food molecules to the parts of the plant where they are needed. (Molecules are tiny particles that make up all living things.)
In this experiment, you can use food color to follow food molecules in a flower petal.

Remove a petal from the flower.
Have more than one person in your group do the activity — then you can compare results.

Cut the pointed end off the petal.

Stick the petal on a piece of tape, with the cut side hanging over the edge.
Make sure the petal is lying flat on the tape.
Stick the petal to the clear stand, with its cut side just touching the white base.

Put a piece of wax paper on the tray, in front of the petal.

Put a drop of food color on the wax paper.

Slide the wax paper under the stand, so the petal dips into the food color.
Start the timer.

Watch the food color creeping up into the petal.
The food color flows along tiny tubes in the petal.
When the timer is done the smaller tubes should be filled with food color.

What pattern is the food color making?
Draw the pattern in your Lab Notebook.
This is the pattern that the tubes make in the petal.

What are the tubes in a petal for?
The tubes carry food molecules to all parts of the petal.

Plants don't just have tubes in their petals.
Tubes are all over plants and carry food molecules everywhere.

We also have tubes that carry food molecules everywhere in our body: our blood vessels.

Our blood vessels have a similar branching pattern to the tubes in plants.

Look for branching blood vessels in your arms.

When you are done, tape your petal in your Lab Notebook or throw it away.

Put another piece of tape over the rest of the petal. (It will stop the food color from making a mess.)

Attached documents: 
Grades taught: 
Gr K
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7
Self guided
Teaching site: 
New York Hall of Science
Activity originally developed and delivered: 

New York Hall of Science