http://www.ck12.org Chapter 3. Measurements
- What is the mass of a cube of copper that is 1.80 cm on each side? The density of copper is 8.92 g/cm^3.
- A balloon is filled with 2300 mL of an unknown gas. The mass of the gas is 3.24 g. Will the balloon float or
sink in air? - A cube of lead (density = 11.35 g/cm^3 ) has a mass of 145.7 g. What is the length of each side of the cube in
cm?
Further Reading / Supplemental Links
- Barber, Jacqueline; Buegler, Marion; Lowell, Laura,Discovering Density. GEMS –Regents of the Univ of
CA, 1998. - Huggins, Shawna,How to Make a Lava Lamp: Exploring Density. Blue and Green Wonders Publishing,
2011. - FunWithDimensionalAnalysis: http://www.alysion.org/dimensional/fun.htm
- Can you make a golf ball float on water? Find out at http://www.youtube.com/watch?v=cXLTSLa3yYs.
- Watch the density of water change when heated at http://www.youtube.com/watch?v=GThtJTncPf0.
- Density differences in liquids and gases can cause convection currents. You can see this at http://www.youtu
be.com/watch?v=ovSMAujQbz4. - Test your skills with a unit conversion hangman game at http://education.jlab.org/vocabhangman/measureme
nt_04/1.html.
Points to Consider
Measurements all must have a certain amount of uncertainty in them, since no measuring tool is 100% accurate. The
uncertainty in a measurement must be considered both when reporting measured values and when doing calculations.
- How is the uncertainty in a given measurement indicated in the reported value?
- When a quantity such as density is calculated from two measurements (mass and volume), is it important to
measure both accurately or is just one sufficient? - What are the meanings of the terms precision and accuracy when dealing with measurements?