Metric Mania-day 2 September 4
Warm - Up:volume, density
Today’s Agenda:1. collect HW2. Notes: Volume & Density
HW:WS: Finding Volume
Reminders:
Turn in Safety Contracts
8
9. volume the amount of space an object takes up
Draw it: Connect it:
displacement method
270 ml - 200 ml = 70 ml
Metric Units
Volume is the amount of space an object takes up.
The base unit of volume in the metric system in the liter and is represented by L or l.
LkL cL mL
Metric Units
Metric Units
1 liter (L) = 1000 milliliters (mL)
1 milliliter (mL) = 1 cm3 (or cc) = 1 gram*
LkL cL mL
Which is larger?
A. 1 liter or 1500 milliliters
B. 200 milliliters or 1.2 liters
C. 12 cm3 or 1.2 milliliters*
Measuring Volume
We will be using graduated cylinders to find the volume of liquids and other objects.
Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water.
What is the volume of water in the cylinder? 43 mL
Measuring Volume
Top Image: http://www.tea.state.tx.us/student.assessment/resources/online/2006/grade8/science/images/20graphicaa.gifBottom Image: http://morrisonlabs.com/meniscus.htm
What causes the meniscus?
A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on
the sides.
Measuring Liquid Volume
Ima
ge
s cr
ea
ted
at
htt
p:/
/ww
w.s
tan
da
rds.
dfe
s.g
ov.
uk/
pri
ma
ryfr
am
ew
ork
/do
wn
loa
ds/
SW
F/m
ea
suri
ng
_cy
lind
er.
swf
What is the volume of water in each cylinder?
Pay attention to the scales for each cylinder.
A B C
Measuring Volume of a Solid
10 cm
9 cm
8 cm
We can measure the volume of regular object
using the formula length x width x height.
10 cm x 8 cm x 9 cm = 720 cm3
Measuring Volume of Irregular Object
Amount of H2O with object = 270 ml
- Amount of H2O without object = 200 ml
Volume of object = 70 ml
We can measure the volume of irregular object using water displacement.
13
Density
Density is the mass per unit volume. A measure of how tightly packed matter is. It is a physical property of a substance.
Density = mass / volume
Density of water is 1 g/ml or 1 g/cm3
(memorize this value)
14
Why Objects Float/Sink:
NOT because they are "Light", or "Heavy" because they are more dense (sink), or less dense (float) then the liquid they are in.
Wood Density: ~ 0.7 g/cm3
Pure Water Density: 1.0 g/ml
Iron Density: ~ 7.9 g/cm3
Note: Object that is MORE dense than the liquid SINKS Object that is LESS dense than the liquid FLOATS
15
Sinking and floating does not have to do with only wood and iron Liquids sink and float also in other liquids
Olive Oil Density: 0.9 g/ml
All the delicious things that make up Italian dressing Density: More than 0.9 g/ml, sink to the bottom