8th Grade Earth Science

There are many cycles throughout the universe.

1. All types of rock buried deep enough may be reformed by pressure and heat, perhaps melting and recrystallizing into different kinds of rock. These re-formed rock layers may be forced up again to become land surface and even mountains. Subsequently, this new rock too will erode. Rock bears evidence of the minerals, temperatures, and forces that created it. (AKSci - A.7)

o Create a diagram of the rock cycle with labels.

o Identify rocks(types) and place in appropriate place on the cycle.

2. The moon's orbit around the earth once in about 28 days changes what portion of the moon is lighted by the sun and how much of that portion can be seen from the earth--the phases of the moon. (AKSci - A.4)

o Demonstrate phases of the moon with a light source and small sphere.

There is order in the universe.

1. The Solar System consists of nine planets of very different size, whose composition, and surface features move around the sun in nearly circular orbits. Many of these planets have objects that orbit them. In addition to the planets the solar system also includes asteroids and comets. (AKSci - A.3)

o Research a planet and present the information to the class, including a handout, a multimedia portion and an assessment tool (e.g., quiz, crossword)

o Construct a relative scale model of the solar system.

2. The sun is many millions of times closer to the earth than any other star. Light from the sun takes a few minutes to reach the earth, but light from the next nearest star takes a few years to arrive. The trip to that star would take the fastest rocket thousands of years. Some distant galaxies are so far away that their light takes several billion years to reach the earth. People on earth, therefore, see them as they were that long ago in the past. (AKSci - A.3)

o Define the term "light year", and discuss why it is used as a unit of measure for distance in the solar system and universe.

3. For 2000 years the earth was considered to be the center of the universe. Ptolemy, an Egyptian astronomer, devised an earth centered model in the second century AD. to explain the motions of the sun, moon, stars, and planets. In the 16th century a Polish astronomer named Copernicus proposed a sun-centered model which was rejected by nearly everyone at the time. About 100 years later the work of Galileo and Kepler supported the ideas of Copernicus. (AKSci - C.3, C.7, C.8)

o Participate in a mock trial of Galileo.

Natural systems undergo change.

1. Current fossil evidence is consistent with the idea that modern species, including humans, evolved from earlier species. (AKSci - A.13)

o Choose a fossil and trace it to its most recent life form.

2. Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). (AKSci - A.7)

o Conduct a laboratory investigation to demonstrate how constructive and destructive forces can cause changes on the earth's surface. Explain the process(es) involved.

3. On the basis of scientific evidence, the universe is estimated to be over ten billion years old. The current theory is that its entire contents expanded explosively from a hot, dense, chaotic mass. (AKSci - A.3, C.1, C.8)

o Illustrate the expanding universe using a balloon and marker.

Many of the earth's features are the result of processes which occur over long periods of time.

1. Some minerals are very rare and some exist in great quantities, but for practical purposes the ability to recover them is just as important as their abundance. (AKSci - A.4, D.1, D.4)

o Choose a regional mineral of interest (e.g.,gold, copper, lead) and prepare a written research paper on that mineral and present a report to the class with a graphic display.

2. The interior of the earth is hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere. (AKSci - A.7)

o Design a laboratory investigation model to identify the forces and motion in convection currents, then describe and illustrate the relationships between the model and the crustal plates of the earth.