by Naomi White, Science Teacher, Jefferson High School, LAUSD

LESSSON SHEET

[ Student Handout | Data Sheet | Optional Math Problems ]

Time Frame: three periods

Concept:
Velocity is the ratio of distance over time. The rate of the stream flow equals the velocity. The stream gradient (vertical descent/horizontal distance) affects the stream flow. The volume of water passing at a certain location can also be calculated if the stream width and the stream flow is known. All of these factors affect aquatic life and will also determine the damage a pollutant will cause at a given location.

Objective:
Students will measure and calculate the rate of stream flow, stream gradient, and volume of water, using a stream model.

Materials:

per student:

• student handout E
• graph paper
• colored pencils

per group:

• stopwatch
• 1/3 of a 10 foot length of gutter
• indelible ink markers
• meter stick
• two dowels or pencils
• gallon plastic milk jug
• 2 cm, 4 cm, 10 cm, thick piece of wood blocks
• 12 cm to 18 cm high support stand for milk carton bucket
• small leaf
• source of water

Preparation:

1. Cut the ten foot length of gutter into three even lengths.

Procedure:
The lab activity should be done on outdoor tables.

2 days:
1. Discuss stream flow concepts
2. Conduct lab activity

1 day:
1. Students should graph results: velocity versus height of trough for one and two holes.
2. Discuss factors that affect stream flow: stream gradient and volume.