Science 8: Cells, Tissues, and Organ Systems Name: ______HR: ______

Early Cell Theory and the Microscope Date: ____ANSWERS____

Curriculum Outcomes Addressed:
• Compare the early idea that living organisms were made of air, fire, and water with the modern cell theory (110-2)

• Use a light microscope or micro viewer correctly to produce a clear image of cells (209-3)

Use your knowledge of early and modern cell theories and the proper instructions for using a microscope to answer the following questions. You may use your class notes to help you if you are unable to do this on your own.

  1. Compare the early cell theory with the modern cell theory. What did early philosophers and scientists believe, and what do they believe now? Explain the reasons behind each of their theories.(110-2)

Early scientists and philosophers believed that everything around them (including all living things) was made up of four classical elements: Earth (solids), wind (gases), water (liquids), and fire (plasmas). They based this theory on the natural things they saw around them because they could not see beyond what their unaided eyes could see.

With the invention of the microscope in the 1650s came the modern cell theory (what we believe now), which is that all living things are made up of cells. Modern scientists base this theory on what they see under the microscope. The microscope was the break-through that lead to this modern cell theory.

  1. What are two safety rules that you must always follow when using a microscope?
  1. How to carry the microscope: Always carry the microscope with two hands; one hand on the arm and the other on the base.
  1. When moving the objective lenses: Move the objective lenses VERY slowly. Only use the coarse-adjustment knob with the low-power objective (the shortest one). Otherwise the slide or the objective lens could get scratched or broken.
  1. When storing the microscope (objective lenses): Always make sure that the low-power objective lens (the shortest one) is pointing down towards the slide when the microscope is not in use; otherwise, if the stage accidentally were to move, it could break the slide or even scratch or break the objective lenses
  1. List step-by-step instructions for how to properly use a microscope to produce a clear image of a cell. Be as detailed as you can be, as you will be using this information in your upcoming laboratory exercises.

See the “How to use a microscope” notes on the “Intro to the Microscope” ppt presentation (second last slide).

Kluge 2013