Fix the mistake: Observation and Classification of Organisms

Observation and Sketching of Living Things

The biology field of science begins with “observation.” Let us develop the ability to look carefully at living things around us and record their characteristics accurately.

Basic Knowledge

When observing living things, first focus on the relationship between the environment (sunlight, moisture, and temperature) and the organisms living there. During field observations, always record the collection location, collection date and time, and weather.
Use observation tools according to the subject. Use a loupe (about 10×) for stationary objects and plants, a microscope (40〜600×) for finer structures, and a stereo microscope (20〜40×) for microorganisms in ponds and similar subjects, which can be viewed three-dimensionally.
Record observation results with a sketch. Draw with thin, clear, single lines, without shading or filling in areas. Add notes about observations and size in the margins.

Important Terms
Loupe (loupe)（A handheld magnifying glass. About 5〜10×. Hold it close to the eye when using it）
Stereo microscope (stereo microscope)（Used to observe three-dimensionally with both eyes. 20〜40×）
Microscope (microscope)（Used to observe with transmitted light. In middle school, 40〜600×）
Sketch（A diagram that accurately depicts an observation subject with thin lines）
Microscope slide (preparation)（An observation specimen in which a sample is placed between a glass slide and a cover glass）
Objective lens・Eyepiece（The magnification of a microscope is determined by multiplying the magnifications of the two）

Further Study (Background・Significance)

When using a loupe, hold it close to your eye and focus by moving the object (if it can be moved) back and forth. When observing something that cannot be moved (such as a flower or tree), focus by moving your head. Never look directly at the Sun (it can damage your eyes).
Microscope magnification is calculated as Magnification = eyepiece magnification × objective-lens magnification. For example, eyepiece 10× × objective 40× = 400×. As magnification increases, the field of view becomes narrower and darker, so first find the subject at low magnification and then switch to high magnification.
The reason for not shading sketches is that shadows change depending on how light strikes the subject and are subjective information, not morphological characteristics of the organism itself. Objectivity is the highest priority in scientific records.

Key Points
  • Hold a loupe close to the eye. Move movable objects back and forth
  • Never look at the Sun through a loupe
  • Microscope magnification = eyepiece × objective lens
  • Observe from low magnification to high magnification
  • A stereo microscope provides a three-dimensional view
  • Use one thin line for sketches. Do not add shadows
  • Always record the collection location, date and time, and weather

Points to Note (Easily Confused)

① Do not confuse a stereo microscope (three-dimensional observation, low magnification) with a transmitted-light microscope (slides, high magnification). ② Microscope magnification is a ratio of lengths, not areas. A magnification of 400× means that 1 mm appears like 400 mm. ③ Do not reverse the procedure of securing a wide field of view at low magnification before switching to high magnification. ④ A sketch is a record, not a painting. Filling in areas and using hatching are prohibited.

Practice

  1. If the eyepiece of a microscope is 15× and the objective lens is 40×, what is the total magnification?
  2. When observing a movable object with a loupe, how do you focus?
  3. Name one thing that must not be done when making a sketch.

Biology (Junior High): related lessons