TECHNOLOGY: Room 5 from Churchill Park School asked this question.
Ok, there are lots of types of light bulbs! However, they all have two basic things in common. First, they require electricity, which is the first step. The second common thing is that electricity can be used to heat things up – think of how warm your computer gets when you use it a lot and you hear the fan whirring to cool it off, or the charger for your parent’s laptop or phone might get warm when it is plugged in.
Older light bulbs are filament bulbs. A filament is a very, very thin wire, and if you look closely at a light bulb like this you can see these wires. The electricity being run through it causes it to heat up (this is another reason we coat electric cables in rubber). The metal used to make the filament glows when it becomes hot, and thus we have light. Because it is so very thin, it heats up really fast, so when we flick the switch the light comes on! More modern light bulbs replace the filament with a gas. When heated, these special gases glow and create light.
Our expert
Distinguished Professor Geoff Chase from the University of Canterbury answered this question. He is a Fellow of Royal Society Te Apārangi, which means he’s one of the top experts in his field of engineering.
For more information on our expert, visit his profile: Geoff Chase
FAQs
As the current flows through the filament, it heats up and becomes extremely hot, reaching temperatures of over 2,500 degrees Celsius. This heat causes the filament to emit light, which is what we see as the light bulb's glow.
How does an electric bulb produce light? ›
The thin filament inside the bulb is a metal strip, having high melting point. When the electric current is passed through this wire due to the heat produced in the filament, it becomes red hot and produces light.
How does a bulb glow answer? ›
When the electrons flow the current generates, this current also flows throgh the bulb. Generally, an electric bulb has a thin filamemt made of tungsten which offer resistance when current flows through it and hence, the electrical energy changes into heat and light energy. This is how the bulb glows.
How does light make light? ›
Incandescent lights work by putting electricity through filaments, which get hot and light up. Fluorescent lights work by passing electric current through vapor, which produces radiation in the form of light. LED lights use electrons to produce light, and are the most widely available, efficient type of lightbulb.
What makes the bulb light up? ›
Due to the heating effect of electric current, the bulb glows when the electric current passes through it. The filament of the bulb gets heated to a high temperature and it starts glowing.
What creates light? ›
Electromagnetic radiation, such as light, is generated by changes in movement (vibration) of electrically charged particles, such as parts of 'heated' molecules, or electrons in atoms (both processes play a role in the glowing filament of incandescent lamps, whereas the latter occurs in fluorescent lamps).
What gives light in a bulb? ›
The thin wire that gives off the light in a bulb is known as a filament .
Did the light bulb produce light? ›
The light bulb was invented for the purpose of giving off light. It was designed to produce a more consistent, longer-lasting, higher quality light than that produced by oil or gas lamps (which were the standard means of lighting before electric light).
How does electricity produce light? ›
Turning on a light closes a circuit, which allows electricity to flow from one electric wire, through the light bulb, and then through another wire. An incandescent light bulb produces light as electricity flows through a tiny wire in the bulb, which gets very hot and glows.
How do LED light bulbs produce light? ›
LED stands for light emitting diode. LED lighting products produce light up to 90% more efficiently than incandescent light bulbs. How do they work? An electrical current passes through a microchip, which illuminates the tiny light sources we call LEDs and the result is visible light.
When a light bulb connects to an electrical power supply, an electrical current flows from one metal contact to the other. As the current travels through the wires and the filament, the filament heats up to the point where it begins to emit photons, which are small packets of visible light.
How does a light bulb work for kids? ›
Essentially, the lightbulb is a very thin filament of hard-to-melt metal – tungsten, usually – encased in a glass bulb filled with inert gases so that the filament doesn't oxidise and disintegrate. The electricity causes the wire to glow and a portion of that energy is turned into light.
How does a bulb glow so fast? ›
When we switch on any electric circuit, irrespective of length of the conductor, an electric field is set up throughout the conductor instantneously due to voltage of the source connected to the circuit. This electric field makes all electrons to move in a specified direction simultanceouly. hence the bulb glows.
Does a light bulb produce its own light? ›
The heated filament emits light that approximates a continuous spectrum. The useful part of the emitted energy is visible light, but most energy is given off as heat in the near-infrared wavelengths.
How does the electricity flow through a light bulb? ›
The filament sits in the middle of the bulb, held up by a glass mount. The wires and the filament are housed in a glass bulb, which is filled with an inert gas, such as argon. When the bulb is hooked up to a power supply, an electric current flows from one contact to the other, through the wires and the filament.
