Magnetism:
Electromagnetism:
An electric motor in 10 minutes
Fun with High Voltage
A 10 minute railgun
A 30 second motor
Listening to magnetism
Electrochemistry:
A plastic hydrogen bomb
Building your own solar battery
Building a Hydrogen Fuel Cell
Homemade Batteries
Collecting Chemical Elements
Radio:
A quick and simple radio
Building a radio in 10 minutes
Build a portable crystal radio
A radio out of household items
A simple AM transmitter
The Three-Penny Radio
Thermodynamics:
Aerodynamics:
A Bernoulli levitation ball
A Homemade Vacuum Pump
A Classic Propellor Toy
Light and optics:
Simple laser communicator
Make a solar hotdog cooker
A solar powered marshmallow roaster
Biology:
Extracting DNA in your kitchen
Mathematics:
Kaleidocycles
A Geodesic Dome
A Homemade Microgram Balance
Computers and Electronics:
A Computer Controlled Transmitter
A Free Space Laser Data Transmitter
Fun With Solderless Breadboards
A Simple 1 Watt Amplifier

//dirt cheap wireless TX
//generates 38kHz carrier wave on pin 9 and 10
//sends data via TX every 500ms
void setup()
{
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);

  // Clear Timer on Compare Match (CTC) Mode
  bitWrite(TCCR1A, WGM10, 0);
  bitWrite(TCCR1A, WGM11, 0);
  bitWrite(TCCR1B, WGM12, 1);
  bitWrite(TCCR1B, WGM13, 0);

  // Toggle OC1A and OC1B on Compare Match.
  bitWrite(TCCR1A, COM1A0, 1);
  bitWrite(TCCR1A, COM1A1, 0);
  bitWrite(TCCR1A, COM1B0, 1);
  bitWrite(TCCR1A, COM1B1, 0);

  // No prescaling
  bitWrite(TCCR1B, CS10, 1);
  bitWrite(TCCR1B, CS11, 0);
  bitWrite(TCCR1B, CS12, 0);

  OCR1A = 210;
  OCR1B = 210;

  Serial.begin(2400);
}

void loop()
{
  Serial.println("testing testing testing");
  delay(500);
}