Vision Training
Estimate, Compare and Measure
Purpose
Many children have a poor understanding of
concepts such as length, weight, volume and
area. For example many 6 and 7 year old would
not be able to estimate the length of 10 cm.
There are three steps in logical reasoning. The
first is to estimate by visual analysis, the second is
to compare an object against another object and
the third is to use an object as a measuring device.
As a result throughout this activity the child should
be asked to analyse a problem in this order. Many
children are impulsive and will often guess their
answer, by having them estimate it breaks down
this tendency and forces them to use their logical
reasoning abilities.
The child should also be encouraged as much as
possible to manipulate each object by feeling it
in their hands. Effectively their body becomes a
measuring device their hands become scales the
length of their arm a ruler.
The exercise introduces the child to the concepts
of length, weight, volume and area. Each is
discussed further below.
Equipment
Any object from around the house can be used.
Ruler, tape measure, measuring cups, two sets
kitchen scales.
Instructions
Length
Choose two objects from around the house. Make
sure they are objects which can be moved and
aligned. Have the child estimate which one they
think is longer. Once the child has given their
answer they are encouraged to place the objects
side by side to compare. The child should be
encouraged to make sure the objects are properly
aligned. Begin with objects that are quite obviously
different in length as the child’s perceptive skills
improve make the objects closer in length.
Language is important when dealing with maths
concepts such as length. The instructor should
continually encourage the child to use words such
as long, longer, longest.
The child should be encouraged to make direct
and indirect comparisons. For example, “find
something in this room as tall as this book” is a
direct comparison whereas “find an object that is
longer than a cricket bat but shorter than a golf
club” is an indirect comparison.
With practice the child should be able to compare
the lengths of more than 2 objects. Have the child
arrange objects according to their length.
Unfortunately not all objects can be moved
therefore a third object has to be used to measure
the other two objects, this is where we introduce
a measuring device. At this stage the child should
be encouraged to use any object as a measuring
stick.
For example, “How many paces is it from one side
of my living room to the other?” “How many paper
clips is it from one side of my exercise book to the
other?”
Next use a formal measuring device such as a ruler
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or tape measure. The instructor needs to teach the
child how to read the scale and familiarise them
with the concept of centremetres.
The child may still need to use a combination of
measurement devices consider the lines below, the
child is asked to look at them and estimate which
one is the longest, which is extremely difficult by
visual inspection alone. They are then encouraged
to measure each object. For the straight lines a
ruler can be used, for the curved lines the child
may use a piece of string curl it up into the same
shape and then stretch it over a ruler.
Weight
Children’s concept of weight will be poorer in
comparison to length.
Have them arrange objects in increasing and
decreasing order of weight. Have them point at
the heaviest, the next heaviest, the third heaviest
and the lightest. Begin with objects with a large
difference between their weights such as a feather
and a can of soft drink. As the child becomes
competent the objects should be made more
similar.
Again direct and indirect comparisons are useful to
reiterate the concept of weight. For example ask
the child to find something in the room which is
heavier than the remote control, or ask the child to
find something that is heavier than a loaf of bread
but lighter than a box of cereal.
Kitchen scales are invaluable in these types of
exercises. Have the child arrange two scales side
by side and have them compare the difference
between the weight of various objects. Ie. Their
teddy bear or doll.
Once the child recognises the difference in the
weight of various objects the instructor then shows
the child how to read a scale and familiarises them
with the concept of grams. The instructor writes
the numbers down and asks the child which is
more. This will slowly introduce children to number
value. It is not important at this stage if the child
cannot recognize the number but the child must
appreciate that the first number dictates the value.
For example if a teddy bear weighs 500 grams
and a doll weighs 300 grams, the 5 in 500 is more
than the 3 in 300 so it must be more. Also 1000 is
more than 500 because it has 4 numbers whereas
500 only has three.
Volume
Volume is a fun concept to work with because it
involves working with water. Have the child first
estimate then compare the volume of objects such
as a wine glass and a coffee cup, a vase versus a
bottle. The child fills up each object with water and
then measures each by pouring the contents into a
measuring container. The child visually compares
the height of the waterline. To really highlight the
difference the instructor can use different coloured
cordials such that the child has to compare the red
cordial with the green cordial. This can be made
into a game the instructor (or a sibling) can be one
colour and the child the other. Two or more objects
are chosen and the players visually estimate
which objects would contain more or less. After
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estimating they compare by each pouring their
coloured water into the object. The person who
has estimated correctly wins.
Area
Area is another attribute which can be measured.
Again any object can be used as a measuring
device. For example a table cloth can be used
to measure the area of a table as compared to
pieces of A4 paper.
oo The activity could have an environmentally
friendly feel. Each member of the family could
put a bucket in the shower and measure how
much water they use.
oo Pedometers are great. The child can measure
distances in steps and metres. Ie. What is the
distance between home and the corner shop.
oo Cooking is a great way to introduce children to
the concepts of volume and weight. ie. 100g
butter, 2 cups milk.
Area is a more difficult concept to calculate because
it requires an understanding of multiplication
(length x width), at this stage all that is important
is that the child appreciates the concept. The
child should be shown how the length and width
contribute to overall area. For example to measure
the surface area of a table it would require more
A5 pieces of paper than A4 because it is smaller
in length and width
Once the child becomes adept at measuring
objects by length, mass, area and volume have
them compare more than one attribute at once.
For example find two objects which hold the same
amount of water but one is taller than the other.
Other Fun Activities
oo Height and weight charts are useful for showing
changes over time.
oo The child could draw a treasure map of the
backyard with the distances in paces written
between objects.
oo One, two or more children could play a game
like the ‘price is right’ where the children take
turns guessing the weight, length etc of an
object. With each answer the instructor says
more, less, higher, lower.
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