Settle Down: Turbidity and Water Quality
3. Outside Explorations
In this activity, you will test one characteristic of water—turbidity—using soil samples that you collect in your schoolyard or neighborhood. At the end of the activity, you will evaluate your data and discuss the effects of turbidity on the plants and animals that live in the water. Then you will brainstorm ideas for preventing increased turbidity from runoff and soil erosion.
Before going outside, make sure you have the following:
Student Worksheet: Turbidity Data (your teacher will give one to each group)
- Graduated cylinder or measuring cup (300 milliliter (ml) capacity)
- Metric measuring spoon or cup (30 milliliter (ml) capacity)
- Clear glass jar with lid
- Stopwatches or wristwatch with minute and second hands
- White paper
- Tap water in a bucket or pitcher
- Soil sample from your schoolyard or neighborhood.
- Go outside and collect a soil sample from your schoolyard or neighborhood.
- Prepare your glass jar or container. Fill a graduated cylinder or measuring cup with 300 ml of water. Use this water to fill your clear container as follows:
- Add 100ml of water to your jar. Draw a line on the jar at the waterline and mark this line “Zone A – 100 ml.”
- Add another 100 ml of water to your jar. Draw a second line on the jar at the new waterline and mark this line “Zone B – 200 ml.”
- Add the last 100 ml of water to your jar. Draw a third line on the jar at the new waterline and mark this line “Zone C – 300 ml.”
- Before adding the soil to this water, you need to complete the“predictions” sections (1 minute, 5 minute, and 10 minute intervals) on your “Turbidity Data” student worksheet.
- Add 30 ml of soil and use your stirrer to mix completely. Put the lid on the jar and shake the jar well.
- Set the jar down and do not touch it during the next ten minutes, while you are collecting data about its contents, as instructed on the “Turbidity Data” student worksheet. It may be helpful to work in pairs, with one person using the stopwatch and calling the time at 1, 5, and 10 minutes, and the second person making and recording the observations at the moment the time is called.