Australia's Science Forum

Hi everyone,

We have a year 8 prac where students cover leaves with strips of aluminium and
leave it for a few days to show that no starch forms in the covered areas (after further testing
with boiling in metho and using iodine for indicator).

What is the best (pot) plant to use? I'm using geranium, but the leaves are crinkled and the aluminium strips
do not sit flat against the surface. Any suggestions welcome!

Thanks, have a great day.

Our yr 11 Bio class went out to our garden and found some weeds to cover with foil/black garbage bag and they said it worked well.

Geranium plants, they have great resorts from the good old Geranium.

It won't matter if the foil doesn't sit flat on the leaf, as long as there is no light penetrating. So as long as the foil is wrapped around the leaf they will still get good results. Make sure that the plants are in full sun afterwards, inside next to a window will not be sufficient as the glass will interfere with the light transmission.
The students here normally go outside and cover the leaves in situ. There are a few rose bushes close to the labs and these work well.

We use geraniums in the garden. Always give good results.

We have used the new soft leaves of hydrangeas too. Although that may be a challenge this time of the year in some areas as they are deciduous!!

More so in your part of the world, Rae. In warmer climes, they should still have some leaves.

Thanks guys! Looks like we'll stick to geraniums.

We use hibiscus bushes in the garden. That way later we can then compare the variegated leaves v the all green leaves as well.