Fun Science Flower Transpiration Experiment

Find out how flowers and plants bring water up their stems and in to their leaves through transpiration, and personalise a bunch of flowers to make them a unique color to you!

What you will need: A clean vase, white flowers such as carnations or roses, food coloring of your choice, scissors, water.


# 1 – Trim the flowers to length, check they fir the vase. Fill the vase with water and add as much or as little food coloring as you like.

# 2 – Pit the flower in the vase with the food coloring and leave it for a few hours. After about 4 hours the petals should start to be turning the same color as what’s in the jar. The flowers in the picture have been split up the stem ,and placed in different colors to achieve a multicolored rose.

This is why….

The transpiration stream: This is the movement of water up the stem of a plant from root to leaf when water is lost from the plant due to evaporation occurring at the leaves.

Water is absorbed by the root or in this case the stem, also known as the xylem vessel. Water moves up the stem by adhesion (being attracted to the side of the vessel) and cohesion (water molecules being attracted to each other). Therefore when water evaporates from the top, at the petals, it changes the pressure in the stem and pulls up more water to replace what has been lost. As water is clear we can’t normally see this process with the naked eye, but when we add color to the water we can!