Investigation Sequence


Earth Changes

Written by:

Lori Beister & Karla Bennett                 Date


Focus Questions

What are some changes that occur in the composition of the earth?
How do these changes happen?


Content: Earth, Physical, & Life

The Earth is a system that contains composition, structure, processes, and history.

Cross cutting concepts


Science Practice


Personal, Social, Technology, Nature of Science, History


Background information

Some changes of the Earth are abrupt, while other changes happen very slowly.
Layers of rock or soil confirm the long history of changing surface of the earth and changing life forms.
Rock is composed of different combinations of minerals or combinations of other rocks.
Soils have properties of texture, capacity to retain water, and ability to support growth of plants, which can be affected by erosion.
Chemicals released in the Earth’s atmosphere changes the Earth.
Different types of rocks are: igneous-they are made from magma that cools below the earth’s surface, sedimentary-they are made from tiny pieces of sediments from bodies of water, metamorphic-are formed from heat and pressure.

Activity Sequence

1. The affect of acid on limestone
2. Understanding erosion
3. Core sampling in the classroom
4. Edible rocks
5. Fossil fun
6. Stalactites and stalagmites
7. Making a crystal garden

Activity Descriptions

Activity 1
The Effect of Acid on Limestone
Chalk, vinegar (clear), clear plastic cup (10oz.), small pieces of rock (other than limestone)
1. Ask the students what will happen when the chalk is added to the vinegar.
2. Have students pour 4-5 oz. of vinegar into plastic cups.
3. Have students to place a piece of chalk into the vinegar.
4. Allow the acid to react with the chalk and observe at 15-30 minute intervals.
5. Allow the student to view the chalk the next day.
6. Ask students to present their finding to the class.
7. Review how acid rain can be damaging to building over time.

Activity 2
Understanding Erosion
Plywood boards (2’x4’x5/8") and bricks, grass sod (2’x4’), soil and water, and watering bucket (for plants)
1. Ask the students what erosion is and what it is caused by.
2. Have students place a handful of soil on the plywood board.
3. Have the students angle the board by placing one end on a few bricks and the opposite end on the ground.
4. Ask the students to slowly pour water from the watering bucket onto the soil.
5. Ask the students to observe and record their data.
6. Have the students scrape the soil off into a small pile (for recycling purposes).
7. Ask the students to place the grass sod on the board and duplicate the first experiment.
8. Have the students observe and record the data.
9. Ask the students to present their findings to the class.
10. Ask the students to speculate on why trees, plants, and grass are important to soil conservation.

Activity 3
Core Sampling in the Classroom
Three or four different colors of Playdoh, drinking straws, small sharp scissors (manicure scissors work well)
1. Ask students what is the soil on earth like? How do scientist know? Answer: (coring devices) to analyze the soil.
2. Ask the students to flatten several pieces of Playdoh (approximately one inch thick).
3. Ask the students to cut a two-inch piece from the straw (cut the straw for younger students).
4. Demonstrate how to push the straw into the Playdoh.
5. Ask the students to hold a finger over the protruding end of the straw and pull the straw out from the Playdoh. They should notice some Playdoh stuck to the bottom of the straws.
6. Have the students cut the straws carefully away from the Playdoh by inserting the manicure scissors and carefully cutting upward until they are past the Playdoh (cut the straw for younger students).
7. Ask students to carefully remove the Playdoh by pulling the straw apart and pulling the Playdoh out.
8. Ask students to review what they found in their core samples.
9. Ask the students how this compares to the information they suggested at the beginning of the lesson.
10. What use is this information?

Activity 4
Edible Rocks
Samples of rocks (granite, igneous, limestone, sedimentary, gneiss, and metamorphic), several large pieces of rocky road fudge, butter knives, hand lenses
1. What is the earth composed of? Answer: (igneous, metamorphic, and sedimentary) Show them examples and let them use a hand lens to investigate.
2. Ask the students to list the properties of the rocks. Discuss the similarities and differences.
3. Point out to the students that some rocks are actually a mixed variety of several different types of rocks, called conglomerates. These rocks are generally sedimentary rocks that contain several types of rocks cemented together.
4. Have each student obtain a sample of the rocky road fudge.
5. Ask the students cut through the sample at various points, loosening the various "rocks" held in the "conglomerate."
6. Have the students record their observations.
7. Ask the students how the conglomerate rocks compared to the three types of rocks they observed.
8. Ask the students what they observed about the "rocky road fudge" rocks and ask them to compare it to actual conglomerates.
9. Ask where each different component of the fudge represents a different type of mineral (or rock).

Activity 5
Fossil Fun
One plastic or wooden dinosaur skeleton kit (such as those manufactured by Safari LTD. ), plastic container filled with sand , and reference books with pictures of dinosaurs.
1. Explain to students that dinosaurs came from different geological regions and show pictures of some of the recreated dinosaur skeletons.
2. Ask how the bones become preserved in rock. Answer: Layers of mud and dirt harden with pressure over time forming a fossil.
3. Have students sift through the material in their container and find any "bones" that may be present.
4. Ask students to hypothesize to what type of organism the bones might have belonged and encourage them to use reference books to support their predictions.
5. Ask students to put the dinosaur bones together to form a complete specimen.
6. Ask the students to present their assembled dinosaurs to the class along with any facts they discovered.

Activity 6
Making a Crystal Garden
Shallow cake pan, three charcoal briquettes, laundry bluing agent, household ammonia, food coloring, salt, water, and a hand lens
1. Ask the students to indicate some potential uses of crystals.
2. Have the students place the charcoal in the pan and break it up with a hammer.
3. Ask the students to pour salt over the charcoal.
4. Have the students mix 3-4 tablespoons of ammonia with _ cup bluing agent and 1/3 cup of water.
5. Have the students pour the mixture over the briquettes slowly until they are saturated.
6. Have the students carefully squeeze a few drops of food coloring over each of the pieces.
7. Have the students place their pans in a designated area where they can remain undisturbed for 1-2 weeks.
8. Ask the students to observe their crystals carefully every two to three days.
9. Have the students report on the progress of their crystals and how they are formed.

Activity 7
Stalactites and Stalagmites
Two clear plastic drinking cups, Epsom salts, cotton twine, washers, wax paper, scissors, spoon, hot water
1. Ask students how stalactites and stalagmites are formed in caves.
2. Have the students obtain two cups and a piece of wax paper (10cm.).
3. Have students cut twine into pieces 10 inches long and tie a washer to the end.
4. Have the students mix Epsom salts in some hot water and stir until the Epsom salts will no longer dissolve.
5. Ask the students pour the salt solution into the cups. The layer of liquid should be about 1 inch from the top.
6. Ask the students to place the end of the string in the two cups. Make sure they soak the string in the salt solution first.
7. Have the students separate the cups so there is a slight bend in the middle of the string between the cups. Have them place the wax paper directly under the middle bend. Make sure the cups are undisturbed for 3-4 days.
8. Have the students observe the progress of the stalactite/stalagmite formations each day.
9. Ask the students to describe what they have observed.
10. Ask the students to explain the process of formation. Answer: Surface water seeps through porous limestone rock formations, carrying dissolved on to the ceiling of the cave. The mineral/laden water seeps through the cracks in the ceiling. The mineral deposits it leaves forms the stalactite. Some of the water drips down to the floor of the cave where it evaporates, leaving behind the mineral deposit (calcium carbonate) that builds up over time this is the stalagmite.

Dr. Robert Sweetland's notes