The centrifuge is a biotechnology laboratory tool that has been used for hundreds of years. The first centrifuges were powered by a hand crank which was used to spin the holding compartment or compartments quickly around an axis in the center of the machine. Spinning these materials at high speeds applies a pressure to the materials in the centrifuge equal to many times the force of gravity. With this amount of pressure placed on the materials, the less dense materials quickly “float” to the center of the centrifuge while the denser materials “sink” to the outside of the machine. Currently, digital centrifuges are used for many applications and are commonly found in biotechnology laboratories to separate sample components and during purification techniques.
The purpose of this lesson is to explore the concepts behind centrifugal force, perform centrifugation with assistance and determine the accuracy of data collected during an investigation requiring the use of a centrifuge. The following video as well as instructor notes and student notes can be helpful when preparing for the proper use of a laboratory centrifuge.
1. Gather the liquids and mixtures being investigated.
2. Add an equal volume of each liquid to each centrifuge tube and record the location of each sample using the numbers found on the rotor of the centrifuge.
3. Place the centrifuge tubes in either a table top or microcentrifuge being certain arrange the tubes so that the equipment is balanced.
4. Centrifuge the tubes for 2-5 minutes on high speed. Allow the centrifuge to come to rest and gently remove the tubes without disturbing the contents.
5. Record the results on a data table or chart such as the example provided.
6. Repeat using the same liquid samples and centrifuging for 1-2 minutes on low speed.
To conclude this skill building lesson, students have an opportunity to repeat and rehearse the centrifuge technique executed in the hands-on lab they have completed in a virtual lab setting. The NC BioNetwork virtual centrifuge lab affords students a unique way to experience the principles of centrifugation and gained an official certification in proper biotechnology lab tool.