Activity Industry Sector
Health Science and Medical Technology

## Modeling

### Activity Overview / Details

Explain to students that micropipettes are tools used for exact measurements and that these tools are very accurate but also quite expensive so it it very important that the micropipettes are always used correctly. Explain the naming of the different micropipettes- we call them p--- based on the amount they measure. In this class, we will be using p10, p20, p200, and p1,000 pipettes- the p10 is for amounts between .1 and 10 ul; p20 micropipettes are best for measuring volumes between 2-20 ul; p200 for measuring liquids between 20-200; and p1000 for 200-1000. Explain to students that it is very important to always use the pipette that best matches the amount they are trying to measure.

Explain to students that when they use the pipette to hold it in one hand, and with the other hand to adjust the volume by turning the dial. Explain that the window with the numbers is read from top to bottom, and explain how to read the pipet measurements with the different size pipettes (http://ceprap.ucdavis.edu has very good diagrams of this, directions, and worksheets that can be used with this activity).

Tell students that there are 3 don'ts when using pipettes-

1. Don't use the pipette with out a tip ( moisture can damage the pipette).

2. Don't lay a loaded pipette down (it can allow moisture to flow back inside causing damage and contamination).

3. Don't allow the button to snap back.

Show students how to attach tip to pipette. Make sure students understand to carefully take the lid off the tip box, attach tip, being careful not to touch tip, and close box. While demonstrating, make sure student's understand the importance of keeping the box closed on the bench and to not touch the tip to prevent contamination.

Show students how to measure liquid, tell them to push the plunger to the first stop and place the tip in the liquid. Then to slowly release the plunger until it comes to a stop. Explain to students to release the liquid they will place the tip on parfilm or a microtube and press the plunger to the first stop, wait a moment, and then press the plunger all the way down. Making sure not to release the plunger until the pipette tip has been removed from the tube or film. Explain to students that it is very important to not let materials get into the pipette itself as this can damage the pipette, and that you must always use a pipete tip. Show students how to eject the tip, by placing the pipette tip in the biohazard waste container and then pressing the ejector button.