Chapter 4:SPECIFIC GRAVITY IN WOOD Flashcards
Defined as mass per unit volume; the quantity of a
matter into a unit volume of materials
DENSITY
Relationship between the mass of the substance and how much volume it takes up
DENSITY
The mass of atoms, their size, and how they are
arranged determine the density of a substance
DENSITY
The ratio of the oven-dry weight of wood to the weight
of water with volume similar to that of the wood at
specified moisture content.
SPECIFIC GRAVITY
The density of water w/ a temperature of ___ or _____ is commonly used as reference to compute SPECIFIC GRAVITY
4°C; 39°F
In computing the specific gravity of wood at various conditions, what is used as denominator?
volume of the wood
In computing the specific gravity what is used as numerator?
Oven dry weight
DENSITY AND SPECIFIC GRAVITY IN WOOD IS AN INDICATOR OF:
- Strength property
- Utilization value of wood
- Processing qualities of wood
- Measure of the amount of cell wall substances and
the air spaces in the wood.
Regarded to be the most extensively used indicator of wood quality
SPECIFIC GRAVITY
Specific Gravity wood classification:
a. high specific gravity
b. moderately high specific gravity
c. medium specific gravity
High specific gravity = __________
0.701 and above
Moderately high SG = ___________
0.601-0.700
Medium specific gravity = ____________
0.501-0.600
WAYS OF DETERMINING SPECIFIC GRAVITY:
- GRAVIMETRIC METHOD
- FLOATATION METHOD
- MAXIMUM MOISTURE CONTENT METHOD
- X-RAY DENSIOMETRY METHOD
The weight and volume of regular shaped wood are considered.
GRAVIMETRIC METHOD
The wood is allowed to float on water and submerge portion will approximate the specific gravity.
FLOATATION METHOD
The weight and volume of regular and irregular shaped wood.
MAXIMUM MOISTURE CONTENT METHOD
The wood is placed over the film and exposed to an x-ray and when the film is developed, then the specific gravity is determined.
X-RAY DENSIOMETRY METHOD
________________ provides highly accurate measurements of wood density and non-destructive, preserving the integrity of the wood sample for further analysis.
X-RAY DENSIOMETRY METHOD
___________ formula are used to derive or determine the specific gravity of wood at various moisture contents when at least one specific gravity value at a certain moisture condition is given.
BROWNE’S
Density and Specific Gravity provide insights into the _____________, such as strength, hardness, and durability.
physical properties of wood
T/F Density is a dimensionless ratio that compares the density of a material to the density of water.
False
If wood has a specific gravity of 1.00, it means its density ____ that of water
equals
T/F Gravimetric method provides highly accurate measurements of wood density and non-destructive, preserving the integrity of the wood sample for further analysis.
False
