What Happens to Water When it Hits the Ground?

Debra Hornfeldt, Como Park Elementary School, St. Paul, MN based on the lesson How Thirsty is the Ground? In WOW! The Wonders of Wetlands, an educators guide. Britt Eckhardt Slattery, 1995 by Environmental Concern Inc., The Watercourse Page 239
Author Profile

Summary

In this classroom and outdoor lab, students investigate and perform percolation tests on different types of soils and record the results.

Used this activity? Share your experiences and modifications

Learning Goals

Students will test measured sand and clay mixtures as well as found soil samples gathered from the school yard and Como Lake to determine the various percolation rates.

Students will record percolation data.

Students will analyze the collected data and determine the percolation rates of various soil samples.

Vocabulary: percolation, soil, clay, sand, organic material, water cycle

Context for Use

Several days are needed for this activity. One 50 min. class period to test sand clay mixtures, record data and analyze the results. A second 50 min. class period is needed to gather, test, and record data from soils found outdoors. Students should have prior knowledge about the water cycle and have a beginning knowledge of various soil compositions.
materials needed:
2 cups clay cat litter (preferably ground to a fine powder)
1 cup of fine soil
sand from a garden shop
3 same-size, clear jars
measuring cups
watch with a second hand
ruler
student notebooks for recording and analyzing data

Description and Teaching Materials

In small groups students create three "homemade" soil compositions. Sample 1: 3/4 cup sand + 1/4 cup clay (clay is the ground cat litter) , sample 2: 1/2 cup sand + 1/2 cup clay, sample 3: 1/4 cup sand and 3/4 cup clay mix each sample but do not pack the mixtures in clear jars. Pour 1/2 cup of water at the same time into all 3 jars. Time the water percolating through you mixtures. Number sample one should be the fastest, all should percolate in about 5 mins. Record what is noticed. Which sample percolates the fastest? What are your students claims and evidence for their conclusions? During another class period go outside and collect soil samples to test. If you have a wetland area close by be sure to collect from that area as well as two others. Test the three soil samples in the same way pouring 1/2/cup of water and timing the percolation of each sample. Prior to collecting and testing the percolation of the new samples have the student small groups come up with a testable question based on their previous experiences testing soil. Have them write the procedures and results in their science notebooks. Be sure to have the students write their claims with supporting evidence as an evaluative tool for their acquired knowledge and skills.

Teaching Notes and Tips

There are many ways to vary this experiment if time permits. Try using more water, what happens if the soil is saturated? talk about and discuss the origins of clay and sand. Ask students why the water doesn't just soak into the ground in a lake? Why doesn't a lake just disappear in a few days? What do they notice about the soil when they are gathering soil to test? This could tie into a social studies unit about MN and our land of 10,000 lakes.

Assessment

The assessment should be ongoing by monitoring student science notebooks. Do the claims and evidence statements identify the student learning? Does the data support the evidence? If not, did the students understand the process of percolation?

Standards

3.4.3.2.3.1 Water circulates through the Earth's crust, oceans and atmosphere in what is known as the water cycle. Identify where water collects on Earth, including atmosphere, ground and surface water, and describe how water moves through the Earth system using the processes of evaporation, condensation and precipitation.

Recognize that rocks may be uniform or made of mixtures of different minerals

References and Resources