There are a wide variety of research instruments used in scientific research, ranging from simple tools like rulers and thermometers to complex equipment like electron microscopes and mass spectrometers. These instruments are used to collect data, measure physical quantities, perform experiments, analyze samples, and more. Each instrument is designed for a specific purpose and can provide researchers with valuable information to help them answer their research questions. Some common research instruments include spectrophotometers, chromatographs, centrifuges, and PCR machines.