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Meet Mortimer Thumb he's Tom thumb's lesser-known little brother [Mortimer waving next to his brother]

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emphasis on little. For the past year Mortimer has been building his own boat

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he dreams of setting sail in steering his homemade ship from one end of a

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beaker filled with water to the other. When you're Mortimer's size well it's

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safer to dream small. He finally completes his cube-shaped boat and is

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ready for the adventure of his lifetime, but he's a bit nervous he really doesn't [Mortimer looking apprehensive]

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want his boat to sink. So to determine whether or not his boat will float he

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has to consider its density and compare it to the density of water. Well the

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formula for density is just mass divided by volume. Mortimer knows that if his

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boat is less dense than water it'll float if it's denser than water, well then [Boat floating and then it sinks]

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not so much... He knows that the density of water is one gram per cubic centimeter

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even if he didn't know he could figure it out the beaker is a 500 milliliter

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beaker full of water. 1 milliliter is the same as a centimeter cubed so the beaker

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can hold 500 cubic centimeters of water well if Mortimer could get a big person

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to help him measure the mass of the water, he'd find that it comes out to 500 [The beaker of water is put on a scale]

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grams well 500 grams divided by 500 cubic centimeters reduces to 1 gram over

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one cubic centimeter so there you go. All right now for the boat. Mortimer takes a

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couple of separate measurements first he finds the mass of his little boat

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plopping it onto the scale he discovers that the 'Voyager' weighs in at exactly 15

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grams. Next he finds the volume of his boat he knows that the volume of the

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cube is the area cube so he starts by finding the area of one side of his [Mortimer measuring up his boat]

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little boat there, four centimeters times four centimeters is 16 centimeters and

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since he then has to multiply by the depth of the cube, so four centimeters

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there as well, it looks like the volume of his boat is 64 cubic centimeters.

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All right now using the density formula, Mortimer takes the mass 15 [Board showing Mortimer's working]

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grams and divides it by the volume 64 cubic centimeters and he winds up with point

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23 grams per cubic centimeter meaning that the density of his vessel is much

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less than the density of water so this puppy is going to float. Happily Mortimer

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drops his boat into the beaker of water and hops in ready for the adventure of a [Mortimer chucks his boat in and then jumps in himself]

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lifetime, unfortunately he sort of forgot to take into account his own mass... [Mortimer and his boat sink]

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Oh well, little man overboard.

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