Standard 2

Objective 1

Students will understand the relationship between properties of matter and Earth’s structure.

Objective 1: Examine the effects of density and particle size on the behavior of materials in mixtures.

Standard 2.1 VocabularySorting: The process that separates particles based on differences in density and/or particle size.

Mixture: A combination or blend of two or more substances that have not chemically combined. Each substance maintains its own identity.

Particle: A small piece of something. Typically used to represent a small part of matter.

a. Compare the density of various objects to the density of known earth materials.

b. Calculate the density of earth materials (e.g., rocks, water, air). The formula for calculating density is Density = Mass/ Volume Water has a density of 1 g/mL= 1 g/cm3

Material that has a density greater than 1g/mL will sink. Material that has a density less than 1g/mL will float. Example rock sinks, wood floats in water

Density Problems 1) If you have a 4 cm3 sample of rock salt with mass of 10 grams, what is the density?

2) You have a 10 cm3 sample of water with a mass of 10 grams what is the density?

3) You have an unknown metal with a volume of 4 cm3 and a mass of 42.0 grams. Compared to the chart, what is this metal most likely to be?

4) Find the density of an unknown liquid in a beaker. The empty beaker's mass is 165 grams. With the unknown liquid inside the beaker, the total mass is 309 grams. The volume of the unknown liquid is 125mL. Is the liquid pure water? Explain your answer.

Element Density (g/cm3)Hydrogen (H) .00009Helium (He) .00018Aluminum (Al) 2.7Zinc (Zn) 7.13Tin (Sn) 7.31Iron (Fe) 7.87Nickel (Ni) 8.9Copper (Cu) 8.96Silver (Ag) 10.5Lead (Pb) 11.35Mercury (Hg) 11.55Gold (Au) 19.32Platinum (Pt) 21.45

c. Observe and describe the sorting of earth materials in a mixture based on density and particle size (e.g. sorting grains of sand of the same size with different densities, sort materials of different particle size with equal densities).

The earth’s materials are naturally sorted according to density AND particle size.

More dense items settle on the bottom.Items with larger particle size settle on the bottom, then smaller particles fill in the empty spaces between the more dense objects.

d. Relate the sorting of materials that can be observed in streambeds, road cuts, or beaches to the density and particle size of those materials.

Larger, more dense materials are found at the beginning of a stream bed and finer, less dense particles are found at the end of a streambed.

On a beach, more dense particles stay at the bottom of ocean and sand on beach all has the same density.

e. Design and conduct an experiment that provides data on the natural sorting of various earth materials.

Sort silt, gravel, pebbles and rocks and place them in a jar with water.

Shake it up and let the materials settle.How do they settle, and why do they settle that way?

Standard 2

Objective 2

Students will understand the relationship between properties of matter and the Earth’s structure.Objective 2: Analyze how density affects Earth’s structure.

Standard 2.2 VocabularyDensity: comparison of the mass and volume of an object. Calculated as mass/volume.

Atmosphere: various layers of air that surround the earth. The densest layers are closer to the earth, the least dense layers are further away from the earth.

Crust: solid outer layer of Earth where life is found. This is the thinnest Earth layer.

Inner core: centermost layer of Earth. Solid metal, is the hottest and most dense.

Standard 2.2 Vocabulary, cont.

Outer core: Liquid layer of Earth found near the center. Found between the mantle and inner core. Made of metals.

Mantle: semi-solid layer of Earth that takes up the most volume. Found directly below the crust.

a. Compare the densities of Earth's atmosphere, water, crust, and interior layers.The earth is layered because of density. The order from most dense to least: Inner Core – Outer Core – Mantle – Crust – Water – Atmosphere

http://www.learner.org/interactives/dynamicearth/structure.html

b. Relate density to the relative positioning of Earth’s atmosphere, water, crust and interior.

Most dense to least dense from the Earth’s Core to the Atmosphere. The denser the material the deeper it sinks to the center of the earth.

c. Model the layering of Earth’s atmosphere, water, crust, and interior due to density differences.

Layer Approximate Density

Composition

Atmosphere 0.0013 g/mL Gases

Water 1.00 g/mL Liquid

Crust 2.7 - 3.0 g/mL Hard and rocky

Mantle 3.3 - 5.7 g/mL Soft and flexible

Outer Core 9.0 - 12.0 g/mL Liquid nickel and iron

Inner Core 12.7 - 13.0 g/mL Solid nickel and iron

d. Distinguish between models of Earth with accurate and inaccurate attributes.Many models of Earth exaggerate the size of surface features such as mountains. If Earth were shrunk to globe size, it would be very smooth.