Purpose: Study the density and weight density of different materials by measuring their mass and water displacement volume. Compare the weight density of wood to water, and determine the wood buoyancy in water. This is a "virtual" experiment, in which all of the experiment data is provided in these instructions.

1. Fill a graduated beaker with 200ml of water (1ml = 1cm³).
2. Measure the mass of one of each type of the objects provided (be sure to measure to at least 2 significant digits), so one wood, one steel ball and one other object.
3. Measure the volume of each of the objects. This is done by immersing each object completelyin the beaker with water, measuring the volume of the combined water plus object, and subtracting the difference in volume to determine the object volume. Be sure to measure the liquid level at the bottom of the meniscus, and estimate to 1ml precision the volume (so that you have at least 2 significant digits precision).
4. Measure the volume of water again, to measure before immersing the wood block to float.Immerse the wood block in water and allow it to float. Measure the level of water with the block of wood floating. The block of wood should only displace its weight with the same weight of water!
5. Compute the volume of the water (ml) displaced by the wood below the surface by subtracting this combined volume measurement from the water level without the wood.

Object	Mass (g)	Volume of water displaced(ml)
Steel Ball	80	32
Rock	32	20
Wood (submerged)	15	25
Wood (floating)	15	15

Analysis/Summary:

1. Calculate each object density (g/cm³, Kg/m³) and weight density (N/m³), using g=9.8m/s².
2. Construct a table of your measurements and calculations (note weight = mg):

Object Mass Weight Vol Water Dens. Dens. Weight Dens.

(kg) (N) (ml) (g/ml) (kg/L) (N/m³)

Steel Ball 0.080 0.78 32 2.5 2.5

Rock 0.032

Wood (sunk) 0.015

Wood (floating)0.015

Water 1.0 1.0 9800

1. How do the densities and weight densities of the objects compare to each other and to

water?

1. Question:How does the wood weight when floating compare to the weight of water

that is displaced?

Note that you will measure mass in grams (g) and volume in milliliters (ml), but will need to compute the mass in Kg, and convert density to Kg/m³ and weight density to N/m³.

Remember that 1ml = 1cm³, 100cm = 1m, so that 10⁶cm³ = 1m³, 1000L = 1m³.

Also note that 1g of water is the mass of 1cm³ or 1ml of water (1g =1cm³ = 1ml)!

Also note that 1000g = 1kg

Weight density of water is 9.8N/L = 9800N/m³