Holography Creative Commons, Attribution alone (BY)
Authors: Warsaw University of Technology
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In this activity, the student acquires knowledge about basic concepts and parameters related to light being an electromagnetic wave (diffraction, interference), holography, a hologram and physical basis of its functioning. Also, many practical applications of these physics phenomena are described and discussed in the lesson (Head-Up Display, security holograms, holographic firearm sights, holographic interferometry, holographic nail polish, acoustic hologram, holographic memory.) The script includes a number of hands-on activities that illustrate and help to understand the discussed topics in connection with their real-life applications.

Knowledge acquisition gain
  Basics of holography, applications of holography

Workforce in Physics

In the EU, around 540,000 students are enrolled in physics, astronomy, chemistry, and earth science courses. Jobs for physicists, other scientists and engineers grew by 7% in the past five years. Jobs for technicians in the field grew by 2%. Overall, they account for 7% of all jobs in the EU. As of 2016, around 15 million European science and engineering workers are employed. They work in a variety of sectors directly related to physics, including aerospace and defence, energy, engineering, manufacturing, oil and gas, science and telecommunications. Others work in sectors such as IT and consultancy, financial services, legal, transport and utilities. In the next years, jobs for engineers and researchers will increase by 13%, and jobs for science and engineering technicians will increase by 2%.

Discussion with students concerning topics like: reaction time while driving a car depending on prevalent conditions (curvy road, night driving, fast driving). Showing HUD as the solution for problems related to, for example: the necessity of changing the direction of looking or focusing the eyesight while driving. Moreover, in everyday life we can find the application of physical phenomena to for example holographic nail enamel.

Learning by hands-on experience + learning by experimentation + inquiry-based learning

Diffraction of light on the slit/umbrella/CD/DVD. Explaining the phenomena like diffraction/interference/interference fringes. Passing from single obstacle to the periodic one – diffraction grating. Showing the magnification of a photograph and of a hologram under the microscope. Explaining the difference between them. Using a laser pointer with holographic head – the simplified version of for example HUD (Head-up-display) in cars or planes. Experimental part will be carried out by students (with guidance of teacher).

Discussion about synthetic hologram, which was the basis of designing e. g. HUD (flight simulators, F1 simulators), security holograms and holographic gunsights. The discussion with students concerning their up to now life experiences with holography is planned.

Holograms are diffraction gratings. Thanks to the synthetic holograms we can be sure the authenticity of our ID documents. The use of head-up-displays depicting different information on special window without covering the view assures larger comfort while driving. Learning by hands-on experience + learning by experimentation + inquiry-based learning helps to engage students and thus increases motivation for learning.

The development of modern holographic technique does not depend on the scientist gender. The encouragement for girls to participate in classes may be for example using “holography” in nail enamels. Lesson may be led by the female teacher. It is advisable to create groups with similar number of girls and boys

Presenting that the principal idea of holography can be realized in each school – there is no need of expensive equipment. We need only a laser pointer, CD/DVD disc, slit (or two razor blades), umbrella. Additionally, the teacher should use the earlier prepared diffraction grating and the PepperGram Projector.

The invention of photography enabled obtaining still 2D images. The next step was the desire to obtain a 3D photography and here, a holography appeared. In simple words we can say that holograms are in some sense a 3D pictures. The phenomenon of diffraction can be compared to a crowd that presses on the front door in anticipation of the opening of a new supermarket. At the moment of opening the door, the people in the middle will run straight inward. People who engage in the door frame will be “bent: at a larger angle. This is the basis of diffraction phenomenon. Students can create the presentation/movie illustrating the interesting (according to them) applications of holography in their lives. Maybe a brainstorm can be performed to propose new potential application of holography.

Dividing students into several groups. Each group will have to perform simple experiment entitled “CD/DVD disc as reflective diffraction grating”. Determining of distances between the recording tracks on CD/DVD disc. For the carried out experiment students will have to prepare a report containing detailed description of its course and analysis of obtained results. The report will enable reconstructing details of experiment and the comparison of results obtained by different groups. Sharing experimental results and honesty (including admitting to mistakes) are the basis of RRI. In case of having PepperGram Projector, each student can watch a 3D image on his/her smartphone. This element can be shown as an example of the thing that most of the people mix with holography.

The success warranty is performing the experiment illustrating diffraction phenomenon with the slit having small enough width. In case of using the umbrella the cloth should be dense enough. The experiment can be carried out with slits of different sizes. During the experiment with CD/DVD disc it is important to observe more than one spot on the screen.