Science Bus Lesson

Author: Alex Tung

Unit: Energy

Lesson: Alternative Energy

Objectives:

-Illustrate the need for Alternative Energy through demonstration of pollution

-Demonstrate a few different forms of alternative energy and how they work through interactive activities

  • Solar energy – mini-solar car kit
  • Hydroelectric power – mock power plant with paddle wheel hooked up to motor

Introduction:

Discuss need for alternative energy – what is pollution?

-What causes pollution? What are the most common sources? (cars, power plants)

-Demonstration: Light some paper and wood chips in a can, hold a piece of paper or paper towel high above it for a few seconds.

  • Did the flame give off energy?
  • Show the soot deposited on the paper – what is this soot? Where did it come from?
  • Why is pollution bad? (gets into the air we breathe, greenhouse effect)

But we still need energy, right? So how can we get energy without causing pollution?

-Demonstration: Hold cup of water in the air

  • Does the water have energy? (yes, potential or stored energy)
  • Pour the water into a bucket on the floor – what kind of energy does it have as it falls to the floor? Can we use that energy somehow?
  • Why do we build dams?

-Can you think of other clean sources of power?

Small Group Activities

1 – Build a HydroElectric Power Plant

Materials – Bucket, PVC pipe, DC Motor, Wire, LED, plastic paddle wheel (or homemade wooden equivalent with cups attached), pitcher, funnel

Activity

-The idea is to simulate water coming down from a stream source in the mountains to a paddle wheel to generate electricity (Do this in a shady spot so they can see the LEDs light up)

-Have the students assemble the plant so that they pour water from the pitcher into the funnel, down the pipe over the paddle wheel, which is attached to motor/wires/LED, and into the bucket/onto ground

  • Tasks for individual students:
  • Hold motor/paddle wheel
  • Watch LED to see if it lights
  • Hold tubing up (2)
  • Pour water

-Notes:

  • The students might first point the tube horizontally at the end so the water pours gently into the cups – see if they figure out that directing the stream straight down into the cups is most effective for getting the wheel to spin quickly
  • switch in more and more LEDs so they see their plant actually generates quite a bit of power

Questions:

- Where does the water get its energy? (has mass, starts high up)

- What is the energy transfer path? (Stored energy to kinetic to mechanical to electrical to light)

- What are some problems with this energy source? (disruptive to environment, not good if dry season. . . )

2 –Solar Car Speed Trials

Materials – Small solar car kit (solar panel, four wheels with motor), 2-3 desk lamps, masking tape, stop watch.

Activity –

-Main concept is to look at the reliability of solar power and how optimization of energy collection

-Tape off a start and finish line. Have the students set up the desk lamps along the course evenly spaced. Have them time how long it takes the car to get across the course with different configurations of the lamps (different ones on, different orientations, different distances from the track, etc.) The key thing here will be to make sure they change one thing at a time for each run and don’t change things during the run.

-Tasks for each of the students

  • Timer (control of stop watch)
  • Score keeper
  • Array adjuster
  • Lamp adjuster

-If the sun is decent. . .

  • Go outside and do the same experiment, only have them adjust the array to optimize speed
  • What happens if they cast shadows in the path?
  • What would happen if it were cloudy outside?
  • How could you make it so you could use a solar energy when it’s cloudy outside? (energy storage)