Joachim Gretsch - How to improve the image of a camera obscura
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The document discusses an inquiry-based approach to teaching the camera obscura within a middle school optics curriculum, focusing on how students can improve image quality through experimentation. Students are encouraged to conduct independent research, document their findings, and engage in lively group discussions, leading to creative solutions for enhancing the camera obscura's image. The authors conclude that inquiry-based learning positively influences traditional teaching methods and stress the importance of documentation skills in this process.
Joachim Gretsch - How to improve the image of a camera obscura
- 1. How to improve the image of a camera obscura – an inquiry-based approach from the middle school optics curriculum. Joachim Gretsch and Nadine Reddersen Andreanum Hildesheim jogretsch@aol.com The camera obscura (pin-hole camera) and lens images are part of a learning. Starting with the question “How can you improve the image of a phenomena orientated optics curriculum in Lower Saxony. Based on a more camera obscura?” students are given the opportunity to plan and conduct conventional teacher-centered approach, the contribution to be presented their own research into image definition and brightness. demonstrates an alternative which integrates processes of inquiry-based Task: How can you improve the image of More and larger holes Put a cone on the back to eliminate (interfering) light Teaching experiences The task seemed to be very motivating for the s t u d e n t s . M a n y g r o u p s w o r k e d v e r y independently and developed a lot of different ideas – in a variety which we don't know from teacher-centered tuition. There was definitely more room for creativity. Of course, not every idea was a success, but we encouraged the students to document (keep records of) wrong approaches also. On the other hand there was a lively exchange of ideas between some of the groups while they were conducting their investigations. The groups concentrated partly on their self-built cameras, others focused mainly on using the optics kits or changed between both of them. Different groups had the idea of using a lens (a magnifying glass) as they knew that it is an important part of a regular camera. a camera obscura? Still – as foreseen - they had problems finding suitable positions for the lens, the object and the screen (for certain positions there is no chance to obtain an image). Here the teachers gave hints to some groups. After an exploratory phase of 2 hours the groups presented their findings. A compilation of ideas and the way they influence the image of the camera was put up. Geometrical optics: emitter-receiver concept of light; light and shadow; linear propagation of light Students built their own camera obscura out of a crisps can and were introduced to work with a Science Optics Kit (LD-Didactic). Technical equipment Self-built camera obscura, scissors, glue, adhesive tape, different materials like card-board Science Optics Kit LD-Didactic including lenses (f = 5 cm, f = 10cm); slides The black tube with a sandwich paper screen slides inside the can Students‘ Pre - knowledge The students are asked - to form groups and to develop ideas to improve the image of the camera obscura, - to write them down, - possibly to plan the technical realization and - to test them in experiments. Glue a lens behind the hole Lens behind the screen Enlarge holes on the front (more light), also the central hole Image is brighter, but completely blurred. Enlarge (central) hole on the front Reasons (and results): The larger hole lets in more light, so the image becomes larger, more colourful and less defined. enlarged hole smaller hole smaller(central) hole for a sharper image Better definition, more intense colours of the image Reduce the light on the screen (no further documentation) Conclusion We found that inquiry-based learning sequences on subjects of the current curriculum can open up the process of conventional tuition in a positive way. Students are given the opportunity to plan and conduct their own research, the outcome of which can be a broad spectrum of creative ideas. We find it essential that the student groups diligently document their ideas, their experimental process and their findings. In future we would put more emphasis on these documentations, as they help students put together their presentations more efficiently later on. We think it is important to train documentation skills as part of the inquiry-based learning process. Introduction Mount a lamp on the front of the camera for more light After we shone a light on a teddy bear, its image was much brighter. Image is brighter More light Let water drip on to the object Water drips on the object This idea was given up (note the association 'water drip – lens'). More ideas Take a thinner screen (does) not really (work) (transparent sheet instead of sandwich paper) The inside of the tube white instead of black (because black swallows all colours!) Put a lens in front of the screen Lens in front of the screen Better definition, brighter image