Question

Why must the test tubes be thoroughly cleaned and dried when one part of the procedure is completed before starting the next part of the procedure ?

Please help me with this, thankyou so much!
Ms. Sue
Don't you want to make sure that all of the old gunk is out of the tube before putting in new stuff?

Sky
yes i know the answer too , but i don't know how to word it, lol that's why i posted it:)
Ms. Sue
Wash and dry the test tubes thoroughly to be sure any new substances are not contaminated by any other substance.
Sky
thank you Ms.Sue:)
Ms. Sue
You're welcome, Sky.