SCIENTIFIC PROCESSES Estimating and Measuring YOU SHOULD BE ABLE TO: • following a sequence of diagrammatic and written instructions and record estimates and measurements • use appropriate techniques; handle apparatus/material competently and have due regard to safety • calculate magnification • state the functions of the various parts of the microscope • estimate or measure, volume, length, mass, time/rate and temperature • records and organise data using standard measurements • convert units of volume, length, mass, and temperature APPARATUS THAT MAGNIFIES OBJECTS • To magnify means to make something look bigger • Apparatus that can magnify an object can be divided into two categories: 1. Hand lens 2. Microscope HAND LENS • A hand lens has a convex glass or plastic lens to bend light, making objects look bigger. • The frame shows by how much an object can be made bigger when looking through the lens. • A stronger magnification shows more detail in a small area. • A weaker magnification shows less detail in a larger area. CALCULATING MAGNIFICATION 1. Measure the length of specimen in the drawing and in real life. (indicate from where until where you are measuring) 2. Use the formula: • E.g. Actual 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑠𝑖𝑧𝑒 𝑚𝑎𝑔𝑛𝑖𝑓𝑖𝑐𝑎𝑡𝑖𝑜𝑛 = 𝑎𝑐𝑡𝑢𝑎𝑙 𝑠𝑖𝑧𝑒 • Magnification does not have a unit. It only has a multiplication sign in front. 𝑚𝑎𝑔 = 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑎𝑐𝑡𝑢𝑎𝑙 3,8𝑐𝑚 𝑚𝑎𝑔 = =× 1,9 2𝑐𝑚 CALCULATING THE SIZE OF AN OBJECT USING MICROGRAPH SCALE LINE • A micrograph is a photo of a structure or object seen under the microscope field. • A scale line or bar is shown on a micrograph to calculate the actual size of the object. • To do so you have to follow the following steps. CALCULATING THE SIZE OF AN OBJECT USING MICROGRAPH SCALE LINE (CONTINUED) 1. Use a ruler to measure the length of the scale line 2. Measure the length of the specimen 3. Use the formula to work out the actual size 4. Round off to the nearest decimal E.g. the scale line = 35mm =100µm The specimen = 70mm 70𝑚𝑚 Then × 100𝜇𝑚 = 200𝜇𝑚 35𝑚𝑚