Archimedes & the King’s Crown Mystery

Volume & Displacement

Part 1 – Volume & Displacement

Materials

·  Ruler and/or tape measure

·  Foam blocks

·  Measuring cup

Mystery

Can you figure out:

·  How to measure volume using water?
Hint: 1mL = 1cm3

Shape / Dimensions (cm) / Formula / Volume (cm3)
(using ruler) / Volume (mL)
(using water)

Part 2 – King’s Crown Mystery

The King has asked for your help:
He gave 5 of his precious golden objects to 5 goldsmiths.
He asked them to make him 5 golden crowns for his 5 cats.
He is worried some of the goldsmiths cheated him.

Materials

·  Large Cup

·  1 “golden” Crown

·  Syringe (12mL)

Mystery

Can you figure out if your goldsmith used all the gold to make the crown you are testing (or if he stole and kept some)?

Remember to be very careful, the king trusts you. If you say the goldsmith stole some gold, he will be fed to the king’s pet dragon. Someone’s life is in your hands. Do your best science!

The king remembers the sizes of each special golden object he gave to each goldsmith:

Name / Shape / Dimensions (cm)
Merek / Cube / a = 4.5
Guinevere / Sphere / d = 5.6
Rowan / Cylinder / d = 6 h = 3.2
Althalos / Rectangle / a = 3 b = 3 h = 10
Victoria / Pyramid / b = 3 h = 30

Calculations

  1. Figure out how many cubic centimeters cm3 of gold the king gave your goldsmith.
  2. Measure the volume of the crown your goldsmith made.
  3. Tell the king if your goldsmith should be rewarded, or fed to the dragon – and why!

Volume of king’s gold: ______cm3

Volume of gold in the crown: ______cm3

Don’t forget to think about how accurately you are able to measure. If your numbers don’t match perfectly, it might be because of your measurements, not the goldsmith.

The king’s counselor, Mr. Dash, suggests you allow up to 5cm3 of error due to experimental error, before you accuse the goldsmith (or you’ll be the one being fed to the dragon)!

Go Further at Home (Bonus) – Archimedes

This lab is based on the story from history about Archimedes. In the legend it is said that the king had a crown made with gold he gave the goldsmith, but was worried the goldsmith had kept some of the gold and instead mixed some silver into the gold.

The crown weighed the same as the amount of gold the king gave the goldsmith.

But without melting the crown down the king had no way to see if the crown was the same volume of metal.

Silver weighs less than gold. So if the goldsmith used silver he would have had to use more of it than the gold.

  1. See if you could solve the real mystery for the king.
  2. Do some research on Archimedes, and the story of him taking a bath and yelling Eureka!

Fun Fact

90cm3 of gold would weigh 1.7kg and be worth $90,000 today!!!

The density of gold is 19.32 grams per cm3

Gold is worth about $50 per gram.