2. Archimedes Dilemma ??????? A long time ago, in the 3 rd century B.C. there was a king in Syracuse (modern day Italy) who wanted a pure gold crown. The royal goldsmith made him just such a crown, but the king thought that maybe the goldsmith had cheated him by mixing the gold and silver to make a silver/gold alloy and keeping some of the gold for himself. The king went to Archimedes, a famous scientist, to solve the problem. What should Archimedes do? Answer will be given at the end of class……..!

3. Density

4. DEF: The amount of matter (mass) packed into a given space (volume). A physical property of matter.

5. Density More denseLess dense Ex: ironEx: aluminum

6. More dense = SINK Less dense = FLOAT Oil Water

7. Source: http://gulfblog.uga.edu/ BP Gulf Oil Spill: If the oil leaked from a pipe near the bottom of the ocean floor, how did it end up at the surface? Answer: Oil is less dense than water so it floats.

8. DENSITY = MASS Volume 10 cm Volume = 10cm x 10 cm x 10 cm= 1,000 cm 3 Mass = 2,000 g Density = 2,000 g 1,000 cm 3 = 2 g/cm 3

9. Another Example: V = 10 mL M = 30 g D = 3 g/mL D = M V D = 30g 10mL

10. Archimedes Dilemma ??????? At first, Archimedes did not know how to test the crown. That is until one day he was taking a bath and noticed how the water went up and down as he entered the baths. Archimedes jumped out of the tub and ran down the streets screaming “Eureka, Eureka!” or “I’ve got it!” He discovered that by placing the crown in the water he could observe the volume of water that the crown displaced. Since he could already measure the mass of the crown, he could find the density of the crown and compare it to the density of gold and silver. Legend has it that the crown displaced more water than gold, but less than silver, proving that the crown was not pure gold.