Engagement/Motivation Activity (5-7 minutes)
The teacher will start the lesson by asking students to predict if there is more land or water on the Earth. Teacher should display the results. Next, students will play a cooperative game using an inflatable Earth (model or globe), preferably with satellite images to show an accurate depiction of the amount of water and land.
Have students identify their right thumb. Where the right thumb lands as the student catches the Earth model determines land or water. The teacher will gently toss the Earth model to individual students to catch with both hands and announce land or water. Students may throw it back to teacher or toss gently to another student. Teacher (or student) will write the tallies on the board marked Land/Water. Teacher will complete ten tosses and have students identify the outcome. Teacher will repeat the process for two additional ten-toss sets. Teacher will ask if there is more land or water based on the outcome of the game. Students should discuss observations with a peer as to why.
Step 1- The teacher is to point out water is a necessity of life, but too much can cause harm. (Show video clip of flooding of Barbour Creek, Eufaula, AL- attached). Then, students will take a walking field trip and record any areas around school that have eroded. Students will discuss and share their findings on the white board or document camera. As a visual example, show the video Erosion and Soil to demonstrate the effects of erosion.
Step 2- The teacher says something like this, “Some man-made structures, like sidewalks, prevent water from soaking into the dirt causing the area around it to erode. If you could create your own sidewalk, what materials would you use that would fix this problem?” Note the materials the students proposed.
Teacher will present the variety of materials to the group. The teacher will divide the class into groups prior to the lesson to allow for diversity within each group. The students will choose a material to test by selecting a tub you have assembled to see what happens when water is applied. Students are to discuss what happens and then discuss if their material is best suited for a sidewalk.
Step 3: Prior to the lesson, the teacher should place tubs around the room, each with a brick on top of the soil to represent a sidewalk. (The various materials are available for groups to test one at a time.) The students will place one material in the tub and add water. The group should observe the outcome, discuss their observations, and record their findings. The number of trials should be determined by the teacher.
Possible observations that should be made are that paper towels, bread, cotton balls, and cardboard soak up the water and are absorbent. Pine straw, pebbles, and sand allow water to pass through but could be carried away.
ASK-Which materials do you think would make the best sidewalk to walk on? Note: Pebbles and sand are a good sidewalk material because it lets water pass through, but it can wash away. Allow 7 to 10 minutes per test sampling to allow for a deep, thorough experiment and discussion. (Use a signal to rotate if more than one test is done.)
Using a document camera or white board, make a chart of the tested materials. Have students display on the list the properties (or findings) they discovered out about their material.
Categorize the findings into absorbent (soaks up), porous, (passes through) non porous (runs off). As a class, discuss the materials that might be best for a sidewalk and why.
Wrap up:
What have we learned?
Earth is 75% water. Water is necessary for life. Sometimes water can wash things away that we have built. Different materials have different properties and some are good for helping things not to wash away.
