What is the purpose of calibrating a 5 ml volumetric pipette

The seven sisters, seven stars located more than 400 light-years away in the taurus constellation can be seen here with venus and another constellation, orion. the seven stars stay grouped together but seem to move, like the planet venus. why do stars seem to move like planets in the night sky?

Carbon tetrachloride (ccl4) is ionic or convalent

Which of the following is a transformer used for? alternate a voltage produce a voltage increase or decrease a voltage eliminate a voltage