Question Video: Using Scales to Measure Mass in Kilograms | Nagwa Question Video: Using Scales to Measure Mass in Kilograms | Nagwa

# Question Video: Using Scales to Measure Mass in Kilograms Mathematics

Fill in the blank: The mass of the puppy is ＿ kilograms.

02:48

### Video Transcript

Fill in the blank: The mass of the puppy is what kilograms.

In the picture, we can see a set of balancing scales. This is the sort of equipment we can use to help weigh the mass of different objects. In this case, we’re using them to measure the mass of a puppy. And we can see the puppy at one end of our measuring scales. And at the other end, we have what look like some metal weights. Can you see what’s written on them? Each of the weights is labeled one kg or kilogram. So how many kilograms are at this end of our scales? There are four of them. Each one is worth one kilogram, so we can say that there are four kilograms altogether.

Now our question asks us to fill in the blank with the mass of the puppy. In other words, how heavy does the puppy weigh? Well, we could just look at our kilogram weights and say it weighs four kilograms. And that it’s actually the right answer. But before we say that, we need to think carefully. Why is the mass of the puppy four kilograms? And it’s not just because four kilograms are on the other end of our scales.

These scales have four kilograms at one end and a puppy at the other. But on these scales, the puppy is lower than the four kilograms. If our scales look like this, we would know that the puppy was heavier than four kilograms. It would weigh more than four kilograms. And if our set of scales look like this, again, we’d still have four kilograms on one end and a puppy on the other. But this time, it’s the four kilogram weights that’re heavier. This end of our set of scales is pushed down. The puppy is lighter than four kilograms. And so in this example, we would say that the puppy is less than four kilograms.

Now, let’s come back to our picture. How would you say we know that the mass of the puppy is four kilograms? Yes, there are four kilograms at one end and a puppy at the other. But the important thing is that our scales are balanced; both ends of the scale weigh the same. The mass of the puppy is equal to four kilograms. Can you see how they’re both level with each other? We didn’t just find the answer by counting the number of kilograms. We looked at the fact that our weighing scales were balanced. And we know now that the mass of the puppy is four kilograms.

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