Speakers have only one job. To deliver sound! Whether it's your iPod, radio, or television, without speakers you wouldn't be able to hear anything. From currents, to magnets, coils and cones, and amplification and volume, all the intricate parts of a speaker are addressed to show how they make sound possible. So, put your headphones on and start listening to your favorite sounds! This book will allow students to plan and conduct investigations to provide evidence that vibrating materials can make sound and that sound can make materials vibrate.