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ENERGY AND COLOUR MATTER
Objectives:
- Do some colors absorb more sunlight than others? Let students find out.
- To introduce children to the concept that different colours influence energy consumption
- To get children to take up a short study to understand the same
Requirement:
- 4-5 tall clear glasses/ glass bottles/ jars
- Water
- Food colour (4-5 different types of colours)
- Immersion thermometer
- Notebooks and pencils
Time required:
- 15 min for the experiment.
- 15 min for introduction and recap
Background:
- Teachers could initiate a discussion with students about the influence of colour on energy consumption, with a relatively familiar concept of clothing colour and absorption of heat. You could discuss with students that individuals would prefer to wear lighter shades of garments as against black and other dark shades on a hot sunny day.
- You could then get them to understand that the same principle has a significant impact on or within a house. Light coloured roofing will help reflect radiant energy whereas dark colours will absorb light. Within the house too, the colours used for painting the walls do influence the electricity consumption. Dark walls absorb more light and reflect less. Consequently, far more lighting is required for rooms with dark walls than those with light walls. This concept could be understood through a simple experiment, procedure for the same is detailed below.
Procedure:
- Fill the glasses/ bottles with equal quantity of cold water. Record the temperature of the water.
- Add 20 drops of different food colours (red, yellow, blue, orange, etc) to the different glasses/ bottles of water to obtain coloured water.
- Retain one glass with plain water as your control sample.
- Place all glasses containing plain and coloured water in a sunny place for 15 minutes.
- After 15 min, record the temperature of the water in all the glasses/ bottles.
- Compare the temperatures recorded from different samples of coloured water and discuss your observations. Did the temperature of the water change? Which water got warmest? What did you learn about colours and light?
Extension and Variation:
- In an apartment complex, where one could find rooms of almost the same size, students could find out the colours used for painting the interiors and the number and lumens (this would be indicated on the light source or its outer packaging) of the light source used for lighting these rooms. Students could then try to find a relation between the number of lights, lumens and the colour used for painting the walls of the rooms. This could help draw a correlation between colour and energy consumption.
ENERGY EFFICIENCY
Objectives:
- Make students aware about the BEE “STAR labeling programme”.
- Get students to find out how many types of equipment in the schools and those in their individual homes have the “STAR labeling”. Alternatively students could also visit a show room selling electrical appliances.
- Make students aware about the relevance of more stars; electricity consumption units per year or fuel economy on different electrical appliances/ vehicles, etc. on the label.
- Discuss findings with the students
Requirement:
- Colour copy of the BEE “Star Label” to familiarize children with the same
- Writing material including notebooks
Time required:
- 1 hour for introduction and recap
- 1 to 2 days for the survey
Background:
- Energy Conservation Act was enacted by the Parliament, in 2001. On 1st March 2002 Bureau of Energy Efficiency (BEE), a statutory body under Ministry of Power, was set up. One of the Regulatory functions of BEE, is to develop minimum Energy Performance Standards & Labeling, for equipment / appliances and buildings. The scheme for energy efficiency labeling of equipments was put in place from 2006 and that for energy efficiency labeling of buildings was developed in February 2009 To start with participation in the scheme was voluntary. Since 2010, BEE star ratings have been made mandatory for some of the electrical equipments. Some examples have been indicated in the Additional Resources.
Procedure:
- Introduce to students in the class the concept of the BEE Star label by showing them a colour picture of the same.
- Familiarize students how to read these labels – the importance of the coloured stars and the importance of the electricity units consumed by the equipment and where the same is mentioned on the label (some of the relevant information is provided in the Additional Information)
- Introduce students to the different electrical equipments which are certified by the Star label
- Ask students to individually or in groups find out different electrical equipment both in the school and in their homes and find out whether the same are certified
- Once the survey is complete, discuss with students their findings.
- Finding of the students could also be represented on the Eco-Schools notice board.
Additional Information
Energy consuming electronics and electrical equipments are today an integral part of our lifestyle. These equipments can be found in different types of buildings including homes, institutions like schools and colleges, hospitals, offices and shopping areas to mention a few. Some of these electronic equipments include refrigerators, washing machines and air conditioning units, tube lights, ceiling fans, colour TVs, electric geysers to name a few.
Depending on whether we are purchasing an electrical equipment for the first time or upgrading/replacing an existing item, various factors such as cost, size, design, features, color etc. feature in our priority list. An important factor that needs to be borne in mind is the amount of electricity that an appliance consumes when it is operated. What would be more useful in the long run is an appliance which would cost less in its operational cost.
In order to understand the cost efficiency in terms of operation, Bureau of Energy Efficiency (BEE) under the Ministry of Power, Government of India has developed a star rating scheme which makes consumers aware about the energy efficiency of an electrical appliance. The idea behind providing this information to consumers is to make informed decisions (about the energy saving potential and costing) while purchasing appliances. Ratings have also been developed for buildings and vehicles. The rating grade of Equipments/ Buildings indicates energy efficiency, starting from one star for the least energy-efficient, and going up to five stars, for the most energy-efficient.
Star Rating labels are of two kinds, the bigger label for bigger electrical equipments including refrigerator, geysers among others and smaller labels for equipments like TVs, computers/ laptops, fans and tube-lights. (as indicated below)


Some of the appliances for which BEE ratings are applicable from 2006 | |
1. Frost Free (No-Frost) refrigerator 2. Tubular Fluorescent Lamps 3. Room Air Conditioners 4. Direct Cool Refrigerator 5. Distribution Transformer 6. Colour TV | 7. Induction Motors 8. Pump Sets 9. Ceiling Fans 10. LPG Stoves 11. Electric Geysers |
WASTE HEAT
Objectives:
- To compare and understand the amount of heat given out by different lighting devices
Requirement:
- Lamp
- Thermometer
- 100 watt Incandescent bulb
- 100 watt CFL
- 100 watt LED bulb
- Other devices of comparable wattage
- Notebook and pencil
Time required:
- 15 min for the experiment.

Background
Procedure:
- Put a 100 watt incandescent bulb in the lamp and turn it on.
- Hold the thermometer six inches above the bulb for one minute and record the temperature. Turn off the lamp. Let the bulb cool, remove it,
- Put in the 100-watt CFL and turn it on. Repeat the above steps.
- The same procedure needs to be repeated with the different lighting devices you wish to compare.
- After documenting the results obtained (as indicated in the table below) it is important to compare and understand the amount of heat which is produced from different lighting devices.
Lighting device | 100 w incandescent bulb | 100 w CFL | 100 w LED | Other devices |
Temperature recorded for 1 min |