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Student Activity - Picture dictation
Activity idea
By the end of this activity, students should understand what happens to the wavelength as we move through the electromagnetic spectrum from radio waves to gamma waves.
When students engage with a learning experience through more than one mode, they tend to remember and understand more. Picture dictation is a strategy that integrates oral, written and visual language skills in one activity.
This strategy involves the students in:
- listening carefully to the story (statements)
- transforming that information into visuals
- orally putting the visuals back into words
- writing captions to match the visuals
- rereading these statements.
Instructions
- Select a clearly sequenced text (e.g. a list of instructions or steps in a process) and divide it into eight to ten simple statements. An example is given below for the electromagnetic spectrum.
- Ask the students to each draw up a page with numbered boxes, one box for each statement. Alternatively, you may want to provide a page with boxes drawn and spaces for the caption to be written for example:
| Picture dictation - electromagnetic spectrum |
|||
|---|---|---|---|
| 1 | 2 | 3 | 4 |
| 5 | 5 | 7 | 8 |
- Read out each the statement and ask the students to draw a simple visual for that statement in the appropriate box (stress that a perfect picture is not required!).
- In pairs, students take it in turns to translate each visual back into words. The students write a caption for each visual and then read their caption to their partner.
The electromagnetic spectrum
- Radiowaves have the longest wavelengths – they are greater than 10 cm. Radiowaves are used for radios, cellphones, televisions, police radars and in industry to melt materials such as plastics.
- Microwaves have a wavelength of 10 cm – 0.01 cm. They are used for heat treatment therapy, alarm systems and heating food.
- Infrared radiation has a wavelength 0.01-7 x 10-5 cm. It is usually described as heat. The most important source of infrared radiation is the sun, although most heating appliances in your home will emit infrared radiation too. Remote controls have an infrared source and your TV has a detector.
- Visible light has a wavelength 7 x 10-5 – 4 x 10-5 cm. The most common form of visible light also comes from the sun. Other sources are light bulbs and lasers. Lasers have lots of uses, for example in CD players, pointers and laser eye surgery.
- Ultraviolet light has a wavelength of 4 x 10-5 – 10-7 cm. The main source of UV radiation is the sun, but it is also generated in industry. It’s used in tanning, dentistry, detecting forged banknotes and treatment of skin conditions.
- X-rays have a wavelength between 10-7 – 10-9 cm. They are used in medicine and airport security. Your doctor uses them to look at your bones and your dentist to look at your teeth.
- Gamma rays have the shortest wavelength at smaller than 10-9 cm. They are used in medicine as a diagnostic tool and to sterilise equipment. They can be used in industry for food irradiation, searching for oil, measurement of water and soil densities and level detectors, e.g. making sure cans of food are filled to the correct level.
Reflective questions
- What is happening to the wavelength as we move through the electromagnetic spectrum, from radio waves to gamma waves?
- Electromagnetic waves carry energy. The shorter the wave, the more energy it carries. Which has more energy – X-rays or microwaves?
