Names: Chiu Chen Ning (L), Lucas Dhiren Max Obé, Everi Yeo Yi Yun, Biswakarma Jaishree
Group Reference: D
1. Indicate the type of research that you are adopting:
[ X ] Test a hypothesis: Hypothesis-driven research
[ ] Measure a value: Experimental research (I)
[ ] Measure a function or relationship: Experimental research (II)
[ ] Construct a model: Theoretical sciences and applied mathematics
[ ] Observational and exploratory research
[ ] Improve a product or process: Industrial and applied research
Title: Investigation of the most efficient type of light bulb. This will be measured in a luminosity (lux) to temperature (degrees celsius) ratio.
Global warming, climate change, melting ice caps— these are all events happening in the world that many of us consider small and not important but most of our energy used comes from fossil fuels like petroleum and coal that provide electricity and gas to power our increasing energy needs. These resources are non-renewable which means that we will eventually run out. Most of us take electricity for granted, and we do not realise we are consuming disproportionate amounts of energy.
According to electricity consumption charts, we consume a lot more electricity compared to other countries, which are similar to us. Per capita Singapore used 8404.23 kilowatt hours of electricity and that is the amount of energy produced by burning 723 kilograms of oil.(9) Also, Singapore must import all its crude oil and natural gas. In 2011, Singapore’s total primary energy consumption included approximately 89% from crude oil and petroleum products, 11% from natural gas, and less than 1% from other fuel sources. Final end-users’1 consumption of natural gas rose 15% from 1,256 ktoe in 2012 to 1,442 kilo-tonnes of oil (ktoe) in 2013. The industrial-related sector accounted for 88% (1,272 ktoe) of total final natural gas consumption, while another 6.3% (91 ktoe) was attributed to the commerce & services-related sector. Households consumed 4% (58 ktoe) of natural gas (in the form of town gas) mostly for cooking and water-heating.(10)
There has been enormous hype about new technologies to conserve electricity lately. One of them is the LED bulb. They contain a diode that emits light when sufficient voltage is applied as the electrons recombine with the electron holes to release energy in the form of photons. Several companies that sell these bulbs often state their energy-efficient properties. (there is even an entire magazine dedicated to sharing LED news) Our group was naturally drawn to this and became sceptical about LED properties.(7)(8)
So as to be able to find out the best way to conserve energy, we have decided to carry out this experiment. The type of light bulb we use, greatly affects the amount of electricity consumption for each household, schools and offices. We want to find out which bulb produces the least heat for the most light. Results from such an experiment would teach households which bulbs to really buy if they wanted to save electricity consumption.
2. Write a research proposal of your interested topic in the following format:
A.Questions being addressed
What is the structure of incandescent lights and how to they function?
Light bulbs have 2 metal contacts at its base, which connect to the ends of an electrical circuit. The metal contacts are attached to two stiff wires, which are attached to a thin metal filament. (usually made of tungsten for its high heat resistance) 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 a stable noble gas, such as argon.
When the bulb is hooked up to a power supply, electricity flows from one contact to the other, then through the wires and finally the filament itself. As the electrons pass through the filament, then are constantly colliding into the tungsten atoms that make up the filament. The impact energy excites the tungsten atom, heating it up and gaining energy.
Bound electrons in the vibrating atoms may be boosted temporarily to a higher energy level. When they fall back to their normal levels, the electrons release the extra energy in the form of light photons. However, the light photons released are mostly of the infra-red spectrum, so the tungsten filament needs to be heated to a higher temperature (2200 degrees celsius) to emit light photons of the visible spectrum.(5)
What is the structure of fluorescent lights and how to they function?
The central element in a fluorescent lamp is a sealed glass tube that prevents outside particles from coming in and vice versa. The tube contains a small bit of mercury and a noble gas, typically argon, kept under a very low pressure. The inside of the glass tube is also coated with phosphor powder. The tube has two electrodes, one at each end, which are wired to an electrical circuit.
When the lamp is turned on, an electrical current flows to the electrodes. There is considerable voltage across the electrodes, causing electrons to migrate from one side of the tube to the other. This creates energy, heating some of the mercury in the lamp into a gaseous state. Some moving electrons collide with the gaseous mercury atoms, gaining further energy and become excited, becoming electrons of a higher energy level. When the electrons return to their original energy level, they release light photons.
However, these light photons are of the ultraviolet spectrum, undetectable by human eyes. This is where the phosphor coating comes in. When a photon hits a phosphor atom, one of its electrons jumps to a higher energy level as it heats up. When the phosphor electron returns to its original energy level, it releases light photons, now of the visible spectrum.(4)
3. What is the structure of LED lights and how do they function?
An LED is short for a Light-Emitting Diode. A diode is a simple semiconductor, a material with a varying ability to conduct an electrical current. For LEDs, the conductor material is often aluminium-gallium-arsenide. (AlGaAs) All atoms in pure AlGaAs bond perfectly to their neighbours, leaving no free electrons to conduct electricity. AlGaAs is modified (doped) by adding certain numbers of atoms into it, changing the perfect balance. A semiconductor with extra electrons is called an N-type material. A semiconductor with extra holes is called a P-type material. Free electrons from the N-type material can move to the holes in the P-type material and vice versa.
A diode consists of a section of N-type material bonded to a section of P-type material, with electrodes on each end. When no voltage is applied, electrons in the N-type portion move to the holes in the P-type portion, creating a neutral space where there is a perfectly balanced charge in the middle. (called a depletion zone) When the zone is wide enough, it prohibits further electron and hole travel between the two opposing zones.
To get rid of the depletion zone, connect the N-type side of the diode to the negative end of a circuit and the P-type side to the positive end. The free electrons in the N-type material are repelled by the negative electrode and drawn to the positive electrode. When the voltage difference between the electrodes is high enough, the electrons in the depletion zone are boosted out of their holes and begin moving freely again. The depletion zone disappears, and charge moves across the diode. The holes exist at a lower energy level than the electrons. When the holes and free electrons meet after the depletion zone disappears, the electron loses some energy to ‘fall’ into the hole. The remaining energy is released as a light photon, thus producing visible light for us to see.(6)
How much electricity does Singapore use per capita?
The average Singaporean used 8404.23 kilowatt hours of electricity. As such, Singapore as a whole used 4597113810 kilowatt hours of electricity, or 45.9711381 terawatt hours.
The independent variables are the type of bulb. (incandescent, fluorescent and LED)
The dependent variable is the temperature of the bulb (in degrees celsius) when it is switched on and the light intensity the bulb gives off when it is switched on. (in lux)
The constants are:
(a) The distance between the luminosity reader and the luminous part of the lighting system. (1 metre)
(b) The distance between the heat reader and the luminous part of the lighting system. (0 metres)
(c) Brightness of location before bulb is activated.
(d) Type of power source.
(e) The type of luminosity reader that we are using for all the lighting system.
(f) The voltage of the power source that we are using to light the bulbs. (240v)
LED lights give the highest light-heat ratio. (lux/degrees celsius)
C.Description in detail of method or procedures (The following are important and key items that should be included when formulating ANY AND ALL research plans.)
-Dark location with power socket
Equipment list: Quantity:
-LED bulb (size E27) 2 (1 extra for precaution)
-Incandescent bulb (size E27) 2 (1 extra for precaution)
-Fluorescent bulb (size E27) 2 (1 extra for precaution)
-Extension cord (5-8m) 2 (Precautionary)
-Light bulb socket (size E26) 1
-Electrical adaptors 1 set (Precautionary)
-Lux meter 1
-Digital thermometer 1
• Procedures: Detail all procedures and experimental design to be used for data collection
————CONDUCT INVESTIGATION IN DARK LOCATION————
Connect the power source and light bulb socket.
Screw the incandescent bulb into the light bulb socket.
Activate the power source.
Measure the luminosity using the lux meter and datalogger from 1 meter away from the bulb. (in lux)
Note down the lux reading on a Numbers table.
Measure the temperature of the surface of the bulb after it has been on for 1 minute. (in degrees celsius)
Note down the temperature reading on a Numbers table.
Exchange the incandescent bulb for the fluorescent bulb and repeat steps 3 through 7.
Exchange the fluorescent bulb for the LED bulb and repeat steps 3 through 7.
Tabulate data in Numbers table.
• Risk and Safety: Identify any potential risks and safety precautions to be taken.
1. As this experiment involves electricity, avoid contact with exposed wires or uncovered components of the circuit.
2. As the experiment involves bulbs that may heat up, avoid contact with any part of the light bulb without safety measures like gloves.
3. As the experiment in done in an unlit location, ensure that there are no potentially hazardous materials left lying around.
• Data Analysis: Describe the procedures you will use to analyse the data/results that answer research questions or hypotheses
1. Tabulate the data using 3 graphs, 1 for each bulb. Rows are for different voltages applied and columns are for luminosity in lux and temperature in degrees celsius. (examples below are using random numbers and do not reflect actual experiment results)
2. From this table, we can find out which bulb emits the most light and least heat with minimum voltage (the aim).
D. Bibliography: List at least five (5) major references (e.g. science journal articles, books, internet sites) from your literature review. If you plan to use vertebrate animals, one of these references must be an animal care reference. Choose the APA format and use it consistently to reference the literature used in the research plan. List your entries in alphabetical order.
(9) Singapore Energy Statistics Chapter 1 – Energy Supply. (2013, January 1). Retrieved January 18, 2015, from https://www.ema.gov.sg/cmsmedia/Publications_and_Statistics/Publications/SES 2014 Chapters/Chapter 1 Energy Supply.pdf
(10) Singapore Energy Statistics Chapter 3 – Energy Consumption. (2013, January 1). Retrieved January 18, 2015, from https://www.ema.gov.sg/cmsmedia/Publications_and_Statistics/Publications/SES 2014 Chapters/Chapter 3 Energy Consumption.pdf
(11) Singapore Power. (2014, January 1). Retrieved January 18, 2015, from http://www.singaporepower.com.sg/irj/servlet/prt/portal/prtroot/docs/guid/d06e53be-040d-2f10-81a5-beb38060addd?spstab=Our Services