What is a Bar Chart - Data Handling, Math, Class 7 Video Lecture

good morning children
now we shall learn one more way to
represent data and this is bar chart in
the society there is a park the Society
did a survey to figure out how many
children came to play on Sunday at
different times
let us see what was the data available
at 10 o'clock in the morning that is at
10:00 a.m. 15 children came to play in
the park at 1 o'clock in the afternoon
which is 1 p.m. how many children were
there there were just four children as
it was very sunny and hot
next at 4 o'clock that is at 4 p.m.
there were 25 children in the park and
lastly at 6 p.m. there were 36 children
in the park now let us put all this data
in that tabular form so we will put time
and number of children in a table so at
10 a.m. how many children were there
there were 15 children in the park at 1
p.m. there were just four children in
the park at 4 p.m. 25 children were
there and at 6 p.m. 36 children were
there so we made a table to represent
the data about children in the park at
different times now what else can be
done visually we can use a
to graph to represent this data and the
pictograph will look like this see here
we have time and number of children and
this symbol represents two children so
this was the pictograph we used to
represent the data but what is the
problem with pictograph generally if we
see it is very time consuming to make a
pictograph and also at times it is
difficult to draw and also to read it or
to say to interpret it so is there other
way to do it yes there is let us see
that so here we can use bars of uniform
width and the length of bar can
represent the given number so see here
all the bars are of same width but they
have different lengths because they
represent different numbers now let us
see how to use it in a chart first we
will draw a vertical line and a
horizontal line the horizontal line is
also called x axis and the vertical line
is called y axis now along the
horizontal line we have marked points at
equidistance and let us see this
vertical line we will represent the
number of children and on this
horizontal line we will represent the
time now we divide this vertical line
also add equidistance point and
let's number it as it is representing
number of children so we do it 0 5 10 15
20 25 30 35 and 40 you may ask why did
we choose till 40 only why not till 6070
yes we can do that but since our maximum
data is of 36 children's so it is
sufficient to have this data
representation till 40 only next we put
the different time slots for which we
have collected the data 10 a.m. 1 p.m. 4
p.m. and 6 p.m. now we will draw bars of
different lengths to represent the
number of children but remember the
width of bar should be the same so at 10
a.m. how many children were there there
were 15 children
so where is 15 on this vertical line it
is here so we will draw a bar which is
of length 15 let's place it here at the
time which represents 10 a.m. now at 1
p.m. there are 4 children
so let us draw a bar representing 4
children first the 4 is here on the
vertical axis now we will draw a bar
which is having the same width as this
bar but of length equal to 4 so this bar
represents 4 children and these were the
children present at 1 p.m.
next we need to represent the data at 4
p.m. at 4 p.m. there were 25 children so
let us find where is 25 on this vertical
line it's here now at 4 p.m. we will
draw a bar which is of length equal to
25 but which would be same as these two
bars so here is the bar which represents
25 children present in the park at 4
p.m. now at 6 p.m. 36 children we're
there in the park let's represent it
using a bar so 36 children 36 should be
here approximately so let's draw a bar
which is of length 36 4 6 p.m. you know
this type of representation of data
using bars which are of uniform width
but their lengths represent different
data is called bar chart now let us use
this bar chart and interpret the values
of data now tell me at what time maximum
number of kids were there in the park
this should be easy to answer just by
looking at the chart we can say this
blue colored bar has the greatest length
hence it represents the maximum number
of children and the children were
present at 6 p.m. so we can say maximum
number of children were present at 6
p.m.
next let us find the minimum
merav kids present at a given time this
also we can figure it out visually this
is the bar which has the smallest length
so this represents the minimum number of
children and this is equal to four so we
can say minimum number of kids present
at a given time is equal to four now let
us try to figure out other questions at
what time number of kids was greater
than twenty for this let us draw a
horizontal line add twenty now it should
be clear
whichever bar has length greater than
twenty should be the required value by
us so here if we see this brown bar has
greater length than twenty and this blue
bar has also length which is greater
than twenty and this was at 6:00 p.m. so
we can say at 4:00 p.m. and at 6:00 p.m.
the number of children in the park was
greater than 20 so now you know how to
draw a bar chart and how to read a bar
chart to reiterate what is a bar chart a
bar chart is representation of data
using parts which are off uniform width
but their lengths represent the value of
given data like here bars of different
lengths represent the number of cut like
here bars of different lengths represent
the number of children at a given time
in the park so now you know how to use a
bar chart
that's all for now bye bye children