A Little Bit of Dirt: 55+ Science and Art Activities to Reconnect Children with Nature by Citro Asia

Author:Citro, Asia [Citro, Asia]
Language: eng
Format: epub
ISBN: 9781943147052
Publisher: The Innovation Press
Published: 2016-03-29T04:00:00+00:00

Scientists use tests to determine the percentage of turbidity. For our test, we’ll use a modified version of a Secchi disk—a black-and-white disk used to test how well you can see through water.

MATERIALS

Tall clear plastic cup or jar with a flat bottom

Scissors

Tape

White paper

Permanent black marker

Stream water

Sink water

DIRECTIONS

1.Set the bottom of the cup on a piece of white paper and use a marker to trace around the outside bottom.

2.Cut out the circle of paper you’ve traced.

3.Draw a plus sign with the marker so the center of the plus sign is roughly in the center of the paper circle and the lines of the plus sign extend to the edges of the circle.

4.Color two opposite quadrants of the circle in with black marker.

5.Tape the circle (colored side up) inside the cup on the bottom so that when you look in the cup, you see the pattern of alternating black-and-white quadrants.

6.Fill the cup to the top with clear water from a sink. Notice how easy it is to see the black-and-white pattern on the bottom of the cup.

7.Fill the cup to the top with water from a stream. How hard is it to see the black-and-white pattern? The easier it is, the less cloudy (turbid) the water is and the healthier the stream is. Please note that colored water is not the same as cloudy water. In the fall, many streams collect a high number of fallen leaves and those leaves release tannins, which can give a brownish color to the water. This is not harmful to living creatures. What is harmful is sand, silt, or other floating particles—these are what make it hard for living things in the stream to breathe.

MEASURING TEMPERATURE

If you’ve checked the turbidity of the stream, you probably already have a guess as to whether the stream temperature is high or low (hint: the cloudier the water is, the warmer it is). Warmer water is harder on living creatures in the stream because it holds less air (oxygen) for them to breathe through their lungs.

MATERIALS: Thermometer

DIRECTIONS

1.Place the bulb (the bottom part) of the thermometer completely underwater. You may wish to use a rock or two to hold the thermometer in place.

2.Leave the thermometer for about 5 minutes to give it a chance to measure the temperature of the water.

3.Read the thermometer. Healthy cold-water streams should be 68 degrees Fahrenheit or lower. Healthy warm-water streams should be 89 degrees Fahrenheit or lower.

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