CBSE Book Class 8 Science Activity Back to the Earth

 CROP PRODUCTION AND MANAGEMENT

It was a bright Sunday morning. Working in the garden was the favourite pastime for the Malhotra family.  It was great fun for little Snigdha to help her father clean up the leaves that were shed by the trees. Her  father would then dump them into a pit and cover it.

“Now these leaves would rot and form compost after some time. We could use this compost in place of  expensive fertilizers in our garden”, explained Snigdha's father. What  causes  the  rotting  of  so  many  leaves?  How  do  these  dead  leaves  get  changed  into  such  useful  compost? What happens to the millions of leaves that get shed from trees in forests? The list of questions  that were bothering Snigdha seemed to be endless. Let us findout through this simple activity what  exactly happens when leaves fall on the soil?

You will need: 

a) Leaves of the same tree       e) Brick Powder

b) Graph Paper / Square grid     f) Magnifying glass

c) Garden soil                          g) Distilled water

d) 2 Pots                                h) Khurpi

Take two leaves and attach a piece of paper to  each  of  their  petioles.  Label  them  A  and  B.  Draw their outlines on a graph paper. Count the  total no of squares covered by the leaves to find  their area.

Take  two  pots  1  and  2.  Partly  fill  pot  1  with  garden soil, place the leaf A flat on the surface  and pour some more soil till the pot is full. Take  some  redbrick  powder.  Now  partly  fill  pot  2  with  brick  powder.  Place  leaf  B  flat  on  this  surface  and  pour  the  remaining  brick  powder  on top of the leaf till the pot is full. Keep the  contents  of  both  the  pots  A  and  B  moist  by  adding  water  boiled  &  cooled  to  room  temperature.

Dig up the soil in both the pots every two weeks  to see if there are any changes in the leaves. Bury the leaves again. After two more weeks, dig  up to take out both the leaves. Shake off any soil  from the leaves. Dry both the leaves A and B by  placing  between  blotting  paper.  Draw  the  out  lines on graph paper, marking any holes that have  appeared. compare the area of each leaf with its  original  area.  Replant  the  two  leaves  in  their  respective pots and repeat the above procedure  at 2 week intervals till there is a clear difference  between the two leaves. 

Please refer to the link below - CBSE Class 8 Science Activity Back to the Earth