Video Transcript
Grams
In this video, we will learn how to
use gram weights and a scale to measure the mass or weight of objects. Here’s a set of scales. We use these to measure the mass of
objects. We simply place the object on the
scales, and then we read the scale. The dial on the scale has moved
around, and it’s pointing to the number 100. So the mass of this jar of coffee
is 100 g, which means 100 grams. g stands for grams. This is the unit of measurement
we’re learning about in this video. We use grams to record the mass of
objects.
These scales have numbers in the
middle, which go around in a circle, a bit like a clock. We can think of this scale a bit
like a circular number line. If we were to draw this as a
straight number line, it would start at zero grams. It goes up to 500 grams, and it
goes up in hundreds, 100 grams, 200 grams, and so on. The halfway mark is worth 50
grams. And the smallest divisions are
worth 10 grams. And we know that the dial on these
scales is pointing to the number 100. And the jar of coffee weighs 100
grams.
We call these balancing scales. To use balancing scales, we put the
object that we’re measuring on one side of the scales. And we place gram weights on the
other side until the scales are balanced. To balance the apples, we used a
50-gram weight and two 10-gram weights. 50 plus 10 is 60, and 10 more makes
70. The mass of the apple is 70
grams.
Let’s practice using gram weights
and measuring scales to record the mass of objects.
How much flour is this?
In this question, we’re being asked
to find the mass of the flour. We’re shown a set of balancing
scales. There’s a bag of flour on one side
of the balancing scales. And on the other side, there are
two different gram weights. If we work out the total number of
grams, that will tell us the mass of the flour. The largest gram weight has a
number 50 on it and a “g,” which means 50 grams. And the second weight is a 10-gram
weight. What is 50 plus 10? It’s 60. The mass of the flour is 60
grams.
What is the mass of the can of
soup?
In this question, we have to read
the scales to find the mass of the can of soup. To read the mass, we need to look
closely at the dial on the center of the scale and see which number it is pointing
to. Can you tell what it is?
It helps if we make the scale a
little bigger. Let’s start at zero and count our
way round to where the dial is pointing to. Zero grams, 100 grams, 200 grams,
300 grams, 400 grams. The mass of the can of soup is 400
grams.
What is the mass of the
basketball?
In this question, we have to find
the mass of the ball. But there’s a problem. There’s a ball and a cube or a box
on the measuring scale. This scale tells us the mass of the
box and the ball together. The dial on the scale is pointing
to the number 600. So we know the mass of the box and
the ball is 600 grams.
On the second set of scales,
there’s just the cube. The dial on the scale is pointing
to the number 400, which means the mass of the cube is 400 grams. So we have to find the difference
between 600 grams and 400 grams. What is 600 take away 400? It’s 200.
If the mass of the cube and the
ball together is 600 grams and the mass of the cube on its own is 400 grams, then
the mass of the ball on its own is 200 grams. To find the mass of the ball, we
subtracted 400 from 600. The mass of the ball is 200
grams.
What is the mass of the bread
roll?
In this question, we have to use
the balancing scales and the gram weights to find the mass of the bread roll. We can see that the scales are
balanced, which means that the mass is equal on each side. If we add together all of the gram
weights that we used to balance the scale, that will tell us the mass of the bread
roll.
The largest gram weight has the
number 50. This is worth 50 grams. There are two 10-gram weights and a
one-gram weight. Let’s add these gram weights
together. Let’s start by adding in the ones
column. Zero plus zero plus zero plus one
gives us a total of one. Next, we need to add in the tens
column. Five plus one plus one gives us a
total of seven. 50 plus 10 plus 10 plus one equals
71 grams. The mass of the bread roll is 71
grams.
What have we learned in this
video? We’ve learned how to use gram
weights and scales to measure the mass of objects.
