SUGGESTED STUDENT ACTIVITIES FOR FINDING PI
SUGGESTED STUDENT ACTIVITIES FOR FINDING PI
Students can work in pairs –groups of even 10 or 20 can take part in the playground activities-
Four types of measurements[
mt] are suggested
A [i]
mt of circumference [c] and radius [r]
[ii]
mt of circumference [c] and diameter [d]
B [i] mt
of area [A] and radius
[ii] mt of area [A] and
diameter
C mt of volume
[V] and the parameters needed for using appropriate formulas
D simple cut and paste method given below
A simple fun activity
Draw
a fairly large circle on a cardboard of
medium thickness [ say 10 cm radius] –draw
diameters such that the circle is divided into equal sector shapes [ 12 or 16
or 24 sectors ok]-
A
sector looks like a piece of pizza or
pie or birthday cake i.e conical shape---. cut so many pieces – arrange them in the form of a rectangle- measure the length[ l] of this constructed rectangle- breadth of the
rectangle is the same as the radius[r]
of the starting circle – divide l by r to get pi = [l/r]
Teachers
may show stepwise pictures to students .[tip
for the teachers : cut the last sector into 2 equal small sectors and take them
to opposite ends of the rectangle to give you s decent looking rectangle]
Activities
below are indicated by the types mentioned above-
* type A[i] uses the formula pi =
c/2r -- type A[ii] uses the
formula pi = c/d
**
type B[i] uses the formula pi = A/[rxr]--- type B[ii] uses the
formula pi =4A/[dxd]
** type C formulas depend on the shape of the
volume e.g cylinder, sphere
LIST OF ACTIVITIES
1
circles drawn on plain paper with a compass – known radius
2
circles drawn on graph paper
with a compass – known radius
3
circles drawn on playground with an
improvised compass – known radius
4
half circle drawn on a wall with an
improvised compass – known radius
5
playground fun with human hand-held
circle – both r and d using ropes
[1 to 5 belong type A[i] using the formula given above]
6
circles drawn on plain paper using circular objects –mt of diameter [dia]
7
circles drawn on graph paper
using circular objects – dia mt
8
Circles drawn on playground using
large circular objects – dia mt e.g large wheel. Big drum standing-
9
roll a tin or dabba on the table and measure distance [l]- measure dia using improvised vernier calipers
–stick a thin tape or a thread on the dabba to easily count the number of
rotations[n] – here c= l/n
10
Do
9 above outdoors – use a tyre or wheel or cycle etc.
11
Do 10 above using a drum – have fun kicking the drum carefully
between two straight lines – don’t forget to put a mark on the side of the drum
12
Take a solid pipe – tightly wind a wire
or twine around it – compact the wire/ string leaving no space between rings- count the
number of rings [n]- unwind the wire /string and measure the length [l] – find
dia of the pipe using a vernier – see 9
13
Go to the packing department- take a
roll of cellotape or any thin adhesive tape- make a mark simultaneously [
meaning ‘at the same time’ ‘at one stroke’] in many layers by pricking a pin
radially- unwind the tape and stick it on the side of the table [ i.e along a
perfect straight line] –measure the total length [l]- number or rotations [n =
pricked points ] – see 9
14
This is special for senior iti students
- ask your teacher if he can give you a
gear which converts circular motion [=rotation, revolution] to linear motion –
use the arrangement to measure c. Diameter to be separately found – method
similar to 9 to 13 above
[6 to 14 belong type A[ii] using the formula given above]
15 Draw circles on a graph sheet , using compass
– physically count the small squares , thus finding the area--- radius is known while
drawing the circle – use formula
[[teachers/ volunteers can help in square counting method]
16. In
15 above another person can draw
concentric circles and do as before
[15 to 16 belong type B[i] using the formula given above]
17. Draw circles on a
graph sheet , using available [perfectly] circular objects – physically
count the small squares --- measure diameter- teachers/ volunteers can help to get the dia
from the graph paper itself.
18. If there is a large
room with tiled floor , 17 can be done –
all square tiles is preferred--,
[17 to 18 belong type B[ii] using the formula given above]
19. Volume of a cylinder= [pi]x [ rxr] x [h] use this formula to
calculate pi – a calculator may be needed.
2o use water
and measuring jar/cylinder to find the volume --- many cylindrical
objects can be found around you- tiffin or lunch box, water bottle,
21. Volume of a sphere = [4/3] x [pi] x [ rxrxr]
– this formula can be used – find fairly
spherical shapes which can be filled with water – e.g binthige,
water filled balloon. Rubber ball cut into half
22. volume ofa very long cylinder- take a garden
hose pipe [,the longer the better]—fill
up and carefully pour water into a bucket – carefully measure the volume of
this water – find the INTERNAL DIA by a suitable method- [teachers/ volunteers
can help in this]- stretch and find the length of the pipe [l]- in cylinder formuls use l inplace of h
23. Do 22 above – find CROSS SECTION AREA ,
INTERNAL, by imprint method [ or any other]
[19 to 23- belong type C- use proper formulas]
SETHU BANDHANA TRUST
(FOR UNDERPRIVILEGED
CHILDREN AND YOUTH) Reg. No. 74/ 01-02.
80-G approved
A-1-4, 4TH
MAIN, BOGADI 2ND STAGE (SOUTH) AIISH Layout, MYSOORU, 570026
Ph. 0821- 2342582 / 87627-89139
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