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

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9. volume the amount of space an object takes up

Draw it: Connect it:

displacement method

270 ml - 200 ml = 70 ml

10. density is the mass of the object divided by its volumeDraw it: Connect it:

sink or float?

Volume

T. Trimpe 2008 http://sciencespot.net/

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

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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.

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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)

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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

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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

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WS: Finding Volume

Volume ball = 100 - 80 = 20 ml