Earth Forces Worksheet
World Geography • Unit 1: Physical Geography
Earth Forces Worksheet
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Active Reading & Annotation Directions:
Read each chunked passage below. As you read, interact with the text by completing the following annotations:
Underline Key definitions
★ Star Important facts
Circle Unfamiliar terms
1. Spheres of the Earth
Earth is the largest inner planet, with a circumference of about 24,900 miles (40,060 km). Its surface is split between land and water. The water bodies—oceans, lakes, and rivers—make up the hydrosphere, covering 70% of Earth's surface. Land, including continents and ocean basins, forms the lithosphere (30% of the surface). Surrounding the planet is the atmosphere, a thin layer of nitrogen, oxygen, and other gasses. Finally, the biosphere is the "zone of life," containing all of Earth's living organisms and their immediate environments, overlapping with the other three spheres.
Soporte en Español: La Tierra consta de cuatro sistemas conectados: la hidrosfera (agua), la litosfera (tierra firme y relieve), la atmósfera (gases como el aire) y la biosfera (donde habita toda la vida).
Stop & Jot #1
DOK Level 2
List the four major spheres of Earth. In your own words, briefly explain how they overlap.
2. Earth's Interior Layers
Earth is composed of three main layers: the core, the mantle, and the crust. At the absolute center is the super-hot, solid inner core, made of iron and nickel compressed under extreme pressure. Surrounding it is the liquid outer core, made of the same elements but liquid due to lower pressure. Next is the mantle, a thick layer of hot, dense, semi-soft rock that slowly rises, cools, and sinks, releasing 80% of Earth's internal heat. The outermost layer is the crust, a hard rocky shell broken into tectonic plates floating on the partially melted mantle.
Soporte en Español: El interior consta de un núcleo compuesto por una parte interna sólida y una externa líquida; un manto blando que transporta calor (liberando el 80% del calor interno); y una corteza exterior rota en placas flotantes.
Stop & Jot #2
DOK Level 2
Why is the inner core solid while the outer core is liquid, despite being composed of identical elements?
Forces That Change the Earth Unit Page 1 of 2
Forces That Change the Earth • Page 2
Student Worksheet
3. Internal Forces: Tectonics
About 500 million years ago, Earth's continents were joined in a supercontinent called Pangaea. Over eons, they drifted apart through continental drift. Today, plate tectonics refers to all internal processes creating physical features. The crust's plates float on the semi-melted mantle, moving gradually (about 1 inch per year). As plates crash, pull apart, or slide past each other, they push up mountain ranges, create explosive volcanoes, and release energy as devastating earthquakes.
Soporte en Español: Hace 500 millones de años existió Pangea. Hoy, las placas tectónicas explican cómo se desplazan los bloques de la corteza (1 pulgada por año), chocando y separándose para crear montañas, volcanes y sismos.
Stop & Jot #3
DOK Level 1
Explain plate tectonics and continental drift. How fast do these plates move on average?
4. External Forces: Weathering & Erosion
External forces like wind and water constantly alter Earth’s surface. This involves two distinct processes: weathering, which breaks down rocks, and erosion, which transports them. Weathering is either physical (such as freezing water expanding to crack rocks) or chemical (such as carbonic acid in rain dissolving limestone to form caves). Erosion moves sediment via glaciers (which carve deep valleys), flowing rainwater (forming gullies and canyons), or pounding ocean waves (eroding coastal cliffs).
Soporte en Español: El viento y el agua cambian el relieve exterior mediante el desgaste (meteorización física como congelación de agua, o química como disolución ácida de cuevas) y la erosión (transporte de sedimentos).
Stop & Jot #4
DOK Level 2
Distinguish between weathering and erosion. Give one active example of each from the text.
Inquiry-Based Think-Pair-Share Guide
Instructions: Brainstorm answers independently (Think), discuss and refine with a partner (Pair), and record your finalized class-ready responses below (Share).
1. If tectonic plates continue to drift at 1 inch per year, hypothesize what a physical map of Earth might look like in 100 million years. What major geographic changes do you predict?
DOK Level 2
2. In your opinion, which external force—physical weathering, chemical weathering, or water erosion—has the power to reshape a landscape most permanently? Explain your reasoning.
DOK Level 2
3. Which forces—internal plate tectonics (sudden changes) or external wind/water forces (gradual changes)—do you think have the most profound overall effect in shaping our global societies? Defend your choice.
DOK Level 2
Forces That Change the Earth Unit Page 2 of 2
