One of the most commonly used pieces of equipment in biotech laboratories is called an analytical balance. We can use it to take very precise measurements... four places to the right of the decimal point. Keep in mind that a small paperclip weighs about one gram. In other words the analytical balance isn't designed for weighing heavy items. For example, this balance has a maximum weight of 310 grams. That's about the same weight as a can of tomato soup. Weighing anything larger than that will cause damage. The first consideration is selecting the workspace. The balance needs to be placed on a steady surface such as a marble counter or a lab workbench in order to minimize vibrations. The balance shouldn't be used near doorways or air vents because it's sensitive enough to be affected by air currents. Check to see if the balance is level. Adjust the feet until the air bubble is inside the black ring. If the balance has been unplugged or turned off you need to let it warm up and reach the required operating temperature. Let's try an example. We want to measure out 1.5 grams of sodium bicarbonate. Typically we use weighing paper for measuring anything less than 5 grams. Fold the opposite corners of the weighing paper together and make a crease. Then do the same for the other corners. Place the paper on the balance pan. Close the side doors and press the tare button to zero out the paper. Use a lab scoop to slowly add the sodium bicarbonate to the paper. Close the glass doors and wait for the balance to lock in its reading. Continue adding sodium bicarbonate until you reach 1.5 grams. Close the doors to read the actual weight. 1.5026 grams - and always document your work in your lab notebook. Let's do another example. This time we'll weigh something a little heavier so we'll use a weigh boat instead of paper. Let's measure out 12.19 grams of powdered Tris buffer. Place the weigh boat on the balance pan. Close the side doors and press the tare key. We're aiming for 12.19 grams so the measurement should be within plus or minus 0.02 grams. Always document your work in your lab notebook. Cleaning the balance is an important step, especially at the end of the day. Put it into standby mode or unplug it. Remove the weigh pan and components by lifting straight up. Use a very soft bristle paintbrush to sweep off any powder remaining inside the weigh chamber and in the grooves for the glass doors. Once it's clean, replace the drip ring and the weigh pan. Now you're ready to head into the lab and practice using an analytical balance hands-on. To find in life science course near you visit nccommunitycolleges.edu or ncbionetwork.org.