How do leaves fall off the trees?

Today, Year 2 wanted to find out the answer to “How do the leaves fall off the trees?” They already thought that the wind might blow them off but there is wind in summer too and the leaves stay on – so something must be different!

20131112_10062820131112_095112We went outside to investigate the leaves that had fallen from the trees in our playground and noticed something very interesting. All of the leaves on the ground had big lumpy bits on the end of the stalk. We discovered that as the days get colder, the tree makes this abscission site. It gets very thick and it squeezes the stalk so that all of the water going in and all of the waste coming out gets stuck and it just dies and falls off!

20131112_10025820131112_100757We looked at the lumpy abscission site under the microscope and thought the shape was very interesting. You can see easily where it is squeezing the stalk and everything travelling through it. Then we modelled this process. We were the trees squeezing the (plasticine) stalks until they eventually cut off and fell to the floor. Here is Ben and Mattie to tell you a bit about what they learned!

About lab13network

Lab_13 is a space in a school managed by pupils for pupils to conduct their own research and experiments driven by their curiosity, imagination and enthusiasm, and under the watchful supervision of a Scientist in Residence (not a teacher!!).
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