Video Transcript
Four students have a competition to see who can most accurately guess the mass of a watermelon. Scarlett suggests two kilograms, Michael suggests four grams, David suggests 20 grams, and Madison suggests three metric tons. Who do you think is the winner?
To answer the question, we need to consider the mass of a watermelon. We will also consider the masses suggested by the students and equate each to an object for comparison purposes.
Let’s start with the smallest mass of four grams suggested by Michael. Four grams is a small mass. An example of an object that has an approximate mass of four grams is a nickel coin. So, the question becomes, do a watermelon and a nickel have a similar mass? We know that a nickel is much smaller and lighter than a watermelon, so we know that they do not have similar masses. So we can rule out Michael’s guess of four grams because a watermelon must have a larger mass than four grams.
Now, let’s take a look at the next smallest mass of 20 grams suggested by David. 20 grams is another example of a small mass. Something that measures approximately 20 grams is a mouse. So, do we think that a mouse and a watermelon have a similar mass? We know that a mouse is much smaller and lighter than a watermelon. They do not have a similar mass. So we can rule out David’s guess of 20 grams because a watermelon does not have a similar mass to a mouse.
Next, let’s take a look at Scarlett’s guess of two kilograms. Notice the unit is different. We are now working in kilograms rather than grams. Remember that one kilogram is equal to 1000 grams, so two kilograms is equal to 2000 grams. Two kilograms is a medium-sized mass. An object that has an approximate mass of two kilograms or 2000 grams is a brick. So, do a watermelon and a brick have similar masses? If we imagine holding a watermelon in one hand and a brick in the other, we can guess that a watermelon and a brick are similar in mass. So, this is a possible answer. Let’s look at the last option to check if we are correct.
The last guess suggested by Madison is three metric tons. Three metric tons is a very large mass. It is equivalent to three million grams. Three metric tons is approximately the mass of a killer whale. We can quickly tell that a killer whale and a watermelon are not similar in mass. So, we can rule out Madison’s guess of three metric tons.
So, this brings us back to Scarlett’s guess of two kilograms. A watermelon does have a mass of approximately two kilograms, so the correct answer is Scarlett.
