🧪 The Lab

Try these interactive experiments right in your browser. No batteries needed!

💡 Build a Circuit 💧 Ohm's Law 🌈 Resistor Decoder 📡 Morse Code 📖 Symbols 🏅 Badges

💡 Build a Circuit

Add the battery, add the bulb and close the switch. The bulb only lights up when the loop is complete!

💧 Ohm's Law Calculator

Voltage is the push, resistance is how narrow the pipe is, and current is how much flows. The rule: Current = Voltage ÷ Resistance (I = V ÷ R).

⚡ Voltage (volts, V): A AA battery is 1.5 V. Arduino pins are 5 V.

🚧 Resistance (ohms, Ω):

Tip: a typical LED is happy at about 10–20 mA (milliamps). Real LEDs also "use up" about 2 V, so real engineers subtract that first. Try 3 V ÷ 150 Ω!

🌈 Resistor Colour-Code Decoder

Resistors are too tiny to print numbers on, so they wear coloured stripes! Pick the colours of the first three bands.

Band 1 (first digit) Band 2 (second digit) Band 3 (number of zeros)

Memory trick: Big Brown Rabbits Often Yield Great Big Vocal Groans When... (Black 0, Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Grey 8, White 9). Make up your own!

📡 Morse Code with a Buzzer

Before phones, people sent messages over wires using short beeps (dots) and long beeps (dashes). Type a message and hear it beep!

Your message:

Turn your volume down a little first. Only letters A–Z and numbers work.