Exploring the Blackbody Spectrum Open the simulation on Blackbody Spectrum by clicking the link. A “blackbody” is a term used to describe the light given off by an object that only gives off emitted light, in other words it doesn’t reflect light. Of course in order for such an object to emit light it must get hot. In this lab you are going to observe the nature of light given off by hot objects and determine if there is a relationship between an object’s temperature and the light emitted. Between the graph and the thermometer, click the box that says “Labels.” This will help guide you through understanding the radiation types emitted by each object. 1. Move the thermometer to the light bulb setting. Based on the graph, does the light bulb emit visible light? How can you tell? Yes because it is in the visible light spectrum. 2. Does the light bulb produce X-rays? How can you tell? No because the wavelength of its waves are not short enough. 3. In the spectrum made by the light bulb, which wavelength is most intense and how would you classify it? 0.392, it is visible purple/violet light. 4. Based on the shape of the graph would you expect the light bulb to emit radio waves? Use evidence from the graph to support your response. No because the light bulbs wave that it emits have to short wave lengths. 5. Click the camera icon to save the graph. Then, move the thermometer to the Sun. Note: there is a key that shows you the temperature of each line on the graph. 6. Based on the graph for the Sun, which types of radiation does the Sun emit? How can you tell? UV light because the shortness of the wavelengths of some of the waves the sun emits are short enough to be classified as UV. 7. Compare the graphs of the light bulb and the Sun. What observations can you make? They both emit visible light. 8. Click the camera icon again to save the graph. Then, move the thermometer to the setting for Sirius A. 9. Based on the graph, which types of radiation does Sirius A emit? UV light because it has a wavelength of 100 nm which is the wavelength of UV. 10. Compare the graphs of all three objects. What observations can you make? They all emit visible light, the sun and Sirius both emit UV but sirius A emits an extremely large amount more than the sun of UV. 11. Now you will explore the relationship between peak wavelength and temperature. To help you get the values needed, click the box titled “graph values” above “labels.” Fill out the table for each of the three objects. Object Temperature Peak Wavelength Object Color (star at the top of the graph) Light bulb 3000K 966 NM Orange/yellow Sun 5900K 491 NM White Sirius A 10000K 290 NM Blue 12. Color of visible light is related to wavelength. What do you observe about the color of an object and its temperature? The temperature of the object is related to color because the higher it is there are different colors going from red to blue. 13. This simulation is related to Wien’s Displacement Law. A graphical representation is given below. Based on observations from this simulation and the graph below, what do you believe Wien’s Law states? Wien's law states that different wavelengths will have different colors of visible light.
