What colour surface is best at absorbing infrared radiation?

The aim of my experiment is to find out which colour absorbs the most infrared radiation.

With these experiments I will test the hypothesis that the darker the surface of a material the more infrared radiation is absorbed.

Infrared radiation, also called as “heat radiation” is an electromagnetic radiation that ranges from radio waves (an oscillation with frequency from 10kHertz) to gamma rays (an oscillation with frequency up to 1015GHertz) and includes visible, infrared and ultraviolet light. Electromagnetic radiation is a form of energy.

Clamp

Thermometer

Coloured paper

Light bulb

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Coloured paper

Light bulb

Infrared radiation has frequency between 102GHertz and 4*105GHertz, thus it is just slower than visible light. Light waves with different colour have different frequency (infrared is the slowest while ultraviolet is the fastest).

Each body with a temperature more than the absolute zero emits electromagnetic radiation. The higher the temperature of a body is the more electromagnetic radiation, thus the more energy, it emits. The emitted electromagnetic radiation contains the whole spectrum, however, the higher the temperature of a body is the radiation with the maximum intensity has the higher frequency. Thus, a light bulb with an appropriate temperature can serve as a source of a high amount of infrared radiation, thus heat radiation.

Bodies do not only emit electromagnetic radiation but they also absorb it. The absorption of light depends on the colour of the surface. Dark colours absorb more radiation than light ones.

In my experiment the source of infrared radiation will be a light bulb. As absorption of infrared radiation increases the temperature of the absorbing body I will measure the temperature of different coloured “bodies”. The “bodies” will be 9 different coloured papers consisting of black, brown, pale brown, blue, green, yellow, orange, pink and red. The different colours will be my only variable, the only thing I am going to change. I shall wrap the papers around the end of a thermometer and put it against the light bulb running on 12 volts.

Once the paper has been heated up and has reached its maximum temperature I will read the temperature off the thermometer. My prediction is that the darker the colour of the paper wrapped around the thermometer the higher its temperature will be. I am saying this because black bodies absorb more radiation including all visible light and infrared radiation, whereas light colours reflect more light including visible and infrared light.

I will wrap the thermometer with the same coloured paper three times by paying attention that the layers of the papers between the thermometer and the bulb would be the same every time. The temperature reads will be averaged for every colour. The temperature will only be read when the mercury reaches its highest point and stops rising. The results obtained with one colour are going to be in a tight range, unless there are significant differences in the paper other than colour e.g. size and thickness and how well it is wrapped around the thermometer.

The results will be presented on a chart. The colours of the paper will be shown on the x axis (starting from the lightest) while the temperature will be shown on the y axis.

Peer Reviews

Here's what a star student thought of this essay

skatealexia

15th of Jul 2012

Quality of writing

The candidate includes the experiment in one large block of text which is not brilliant because it makes it hard to decipher each individual section e.g. method, evaluation and conclusion. Spelling, grammar and punctuation are fine.

Level of analysis

In the first instance the candidate explains why they are using the equipment they are using and explains the scientific information behind their reasoning. This is done well but the information is a bit waffly and sometimes hard to understand in places due to the lack of subheadings and clear sections in the text. For example, the picture of the experiment included seems rather random in the place it is now, and it is not until later on we realise the evidence of it. The candidate does not include their results or evaluation or analysis but just an outline of their experiment and their hypothesis.

Response to question

Overall a well explained start to an experiment. The candidate explains the scientific reasoning behind the experiment well in most instances. The main thing the candidate lacks is proper organisation of the experiment into sub-sections, and the results and evaluation of the experiment which is needed to gain a complete view. What the candidate should also consider is what might go wrong with or confound the experiment and thus adjust their method accordingly because this shows greater planning and understanding in their thinking.

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