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A stretched rubber band is a great source of elastic potential energy.. When released, that energy is converted to kinetic (motion) energy.[r]

STEM PROJECT

BUILD A RUBBER BAND–POWERED CAR

1. Introduction

A stretched rubber band is a great source of elastic potential energy When released, that energy is converted to kinetic (motion) energy The energy generated from the rubber band snapping back into shape is enough to power this small car

2. What Happened:

The more you twisted the rubber band around the axle, the more potential energy you built up When you let go, the rubber band snapped back to its original form, spinning the axle in the process The potential

energy in the stretched band was

converted into kinetic energy

propelling the car forward

3. Key concepts

 Physics

 Potential energy

 Kinetic energy

 Conservation of energy

 Simple machine

4. Extra

 Test different types of rubber bands to power your car Does it work

better with long or short ones? Thick or thin ones?  Try using different materials to build your car?

 Do this project with friends or family Everyone can build their own car

5. Materials: This is an engineering design project The following is a suggested list of materials, but you can substitute different ones

 Corrugated cardboard

 Two drinking straws

 Two wooden skewers

 Four CDs (that are okay to get scratched)

 Sponge

 Paper clip

 Assorted rubber bands

 Tape

 Scissors

 Flat, hard surface for testing your car

 Hot-glue gun (optional)

6. How to make a Rubber Band powered Car

7. Consider the following:

 What effect does wheel size have on speed or efficiency?

 What effect does wheel size placement (e.g., larger wheels in back, smaller

wheels in front) have on speed or efficiency?

 What effect does adding weight to your car (e.g., coins, washers, screws) have

on efficiency?

HƯỚNG DẪN GHI NHẬT KÍ DỰ ÁN

Lưu ý:

Nếu HS khơng làm theo nhóm HS khơng trình bày phần Teamwork nhật kí dự án