# Environmental Science

## CONTENTS OF CURRICULUM UNIT 93.05.05

## Environmental Chemistry

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## GENERAL PROPERTIES OF MATTER

Ask the students to list some reasons why the actual mass and the interpolated masses differ.

actual mass—mass from graph % error = —— ———————————— actual mass Volume can be investigated in a similar manner. Introduce the student to the graduated cylinder and the displacement method of measuring volume. Use the same marbles and find the volume for 1, 3, 5, 7, & 9 marbles. Plot this information on a graph of # of marbles vs volume of marbles. Again interpolate the graph for the volume of 2, 4, 6, 8, & 10 marbles and actually measure the volume. Find the per cent error by using the per cent error formula.

Again ask them to list some reasons for per cent error.

Measuring various objects with the meter stick and/or metric ruler will allow the student to become familiar with the metric unit of length. If you have vernier calipers, they can be used by the students to test some volume formulas. I have found they enjoy finding the volume of a coffee can and checking their accuracy by using the graduated cylinder and water.

Density activities are performed first by finding the mass and volume of different numbers of rubber stoppers. Most appear surprised when the answers end up about the same. After these activities have been completed, the idea of density can be reinforced by using different substances of the same volume and constructing a bar graph to visually show the difference in their densities.