Experiment P-31, Light Absorption and Heat
Contents
1. short It is recommended to practice the NeuLog application functions as described in the user manual beforehand 6 Run the NeuLog application and check that the two surface temperature sensors are identified Experiment P 31 Light Absorption and Heat Ver 3 3 11 5 NeuLog x ID numbers setup In order to use two sensors of the same kind they should have different ID numbers Connect one of the sensors and check that it is identified Click on the Tools icon ts in the main icon bar Click on the Set sensors ID button and click on 2 The sensor will change its ID to 2 The Search function will run automatically and you will see that the sensor s module box now shows 2 Disconnect the sensor with ID number 2 and connect the next sensor in order to change its ID Proceed as you did for the first sensor Repeat this procedure for any other sensor of the same kind you want to connect in a chain Once your sensors in this case two surface temperature sensors have different ID numbers you can connect them in a chain Experiment P 31 Light Absorption and Heat Ver 3 3 11 6 NeuLog EJ settings 7 Click on the On line Experiment icon Ga in the NeuLog main icon bar A 8 Click on the Experiment setup icon and set the Experiment duration to 5 minutes Sampling rate to 60 per minute Testing and measurements 9 Cover each probe with a different colored paper 10 Turn on the lamp 112. 1 NeuLog EJ Experiment P 31 Light Absorption and Heat amp Objectives To understand the concept of color To demonstrate the effect of color on light absorption and the conversion of that light into heat using black and white papers To measure body surface temperature while being covered with black or white gloves Modules and Sensors PC NeuLog application USB 200 module Two NUL 233 Surface temperature logger sensors It is also possible to conduct the experiment with one NUL 233 surface logger sensor by measuring sequentially Equipment and Accessories Incandescent light bulb Table lamp Sellotape White paper 5 cm X 5 cm Black paper 5 cm X 5 cm White glove or fabric Black glove or fabric Experiment P 31 Light Absorption and Heat Ver 3 3 11 2 NeuLog EJ Introduction In order to understand color concepts it is first necessary to understand light concepts Visible light waves are seen by the human eye as different colors and they are characterized by their wavelength which is the distance between any two corresponding points on successive waves The length of the wave determines the amount of energy it has the shorter the wavelength the higher the energy Color may also be defined in more subjective terms as something perceived by an individual When light is reflected from an object cones and rods in the retina of the eye respond to the light and the brain interprets the information recei
3. Click on the Run Experiment icon C to start the measurement Experiment P 31 Light Absorption and Heat Ver 3 3 11 7 NeuLog ES 12 In order to focus on the desired range locate the mouse cursor at a point above the graph and press its left button keep it pressed and create a rectangle that includes the whole graph 13 Your graph should be similar to the following NeuLog o amp S Back Save Open Experiment Experiment Surface temperature Surface Temp beneath the black i paper Surface temperature beneath the white paper 1 Unzoom Zoom Zoom Select Line Grid Graph Table Point Area All Fit Zone Width Functions 14 Save your graph 15 We can see that the black paper absorbed more light than the white paper this light transferred to heat which could be sensed by the surface temperature logger sensor 16 Turn off the lamp Experiment P 31 Light Absorption and Heat Ver 3 3 11 8 NeuLog ES 17 Click on the Show Functions icon s and then click on the surface temperature button on the left of the screen You will see the minimum and maximum values 18 Repeat this process for the second sensor by selecting Surface T 2 Maximum 29 30 C 35 EPC Minimum 22 70 C Minimum 72 90 C 19 Fill the table with the minimum and maximum surface temperature values you have recieved 20 Calculate the AT by subtracting the minimum temperature value from the maximum temperatur
4. e value Fill the table with the AT value Minimum Maximum AT C paper temperature C temperature C White J S S S o Black fo d o Challenge research 21 Tape a surface temperature sensor to each palm of your hands 22 Put ona white glove on one of your hands and a black one on the other hand 23 Turn onthe lamp and repeat the measurement while putting your hands on the table next to the lamp In this measurement you will observe the way cloth affects body heat Experiment P 31 Light Absorption and Heat Ver 3 3 11 9 NeuLog EJ Summary questions Lis After this experiment which colors would you prefer to wear in the winter and which colors would you wear in the summer Explain How can we measure the reflected light in the experiments A species of squirrels which displays brown grey or black pelage color was studied Black squirrels showed thinner body hair than other squirrels Try to explain this observation Experiment P 31 Light Absorption and Heat Ver 3 3 11
5. ved as color Light can be directly absorbed by an object reflected at the surface or transmitted through it The electromagnetic spectrum which is visible to us is in the range of 400 700 nm When visible light with an energy distribution similar to sunlight light of all colors completely reflects from an object this light appears white to the human eye When the object completely absorbs all the light it is recognized as black During the absorbing process much of the energy ends up as infrared radiation which can be sensed as heat In the following experiment we will irradiate black and white papers we will measure the temperature beneath them in order to observe the effect of color on energy absorption We will also use gloves or fabrics to see if the body surface temperature is affected by their color Experiment P 31 Light Absorption and Heat Ver 3 3 11 3 NeuLog ES Procedure Experiment setup 1 set up the experiment as shown in the picture below 2 Tape the two surface temperature probes on the table with a distance of about two cm between them 3 Make sure you have a lamp with the bulb positioned 20 cm higher than the probes Experiment P 31 Light Absorption and Heat Ver 3 3 11 4 NeuLog ES sensor setup 4 Connect the USB 200 module va to the PC 5 Check that the two surface temperature sensors are connected to the USB 200 module in a chain Note The following application functions are explained in
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