Video Transcript
Order the animals on the scales, a
duck, a penguin, and a rabbit, from lightest to heaviest.
And if we look at the bottom of the
question, we can see that we have three possible answers to choose from. In this question, we’re shown some
animals on some sets of weighing scales. There’s a duck, which appears
twice. Then, we have a penguin and a
rabbit. And although we don’t weigh all
three objects at the same time, we’ve got enough information here for us to be able
to put these animals in order from lightest to heaviest.
Let’s draw a line to help us. Because we’ve been asked to go from
lightest to heaviest, let’s put the word lightest on the left and heaviest on the
right. Now, the idea behind this line is
it is going to work a little bit like a number line. But instead of putting numbers in
order, we’re going to be putting these animals in order. Let’s look at our first set of
weighing scales. What can we see? We can see the end with the penguin
on it has gone down, and this has pushed the end with a duck on it upwards. Although we’ve only compared two
animals so far, we can tell which one’s heavier, can’t we? The penguin belongs somewhere at
this end of our comparing line because it’s heavier than the duck. And we’ll put the duck at this end
because it’s lighter than the penguin.
Now, let’s look at our second set
of scales. On these scales, we’re comparing
the rabbit and the duck. This time, it’s the end with the
duck on that’s moved downwards, and the end with the rabbit on is lifted up. We can say then that the duck is
heavier than the rabbit. And if we look at our line and we
know that the duck is heavier than the rabbit, we’re going to have to draw the
rabbit to the left of the duck towards the lighter end of our line, aren’t we? The rabbit is lighter than the
duck, and the duck is lighter than the penguin.
Now that we’ve put our animals in
order from lightest to heaviest, can you spot the correct order in the answers? It’s this one. We found that the penguin was
heavier than the duck, but that the duck was heavier than the rabbit. And so, if we order the animals
from lightest to heaviest, the correct order is the rabbit, then the duck, then the
penguin.
