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Grade 6 Beginner About 15 min Version 1 Awaiting review Premium

Reading a measuring cylinder

The volume of a liquid is the space it takes up, measured in millilitres (mL) or litres (L): 1 L = 1000 mL. A measuring cylinder is marked in mL. Water in a narrow glass tube curves at the edges; this curved surface is called the meniscus. Always read the mark level with the bottom of the meniscus, and keep your eye level with it. Looking from above makes the reading too high, and looking from below makes it too low. This mistake is called parallax error.

What you will learn

  • Read the volume of a liquid in a measuring cylinder to the nearest mL.
  • Read at the bottom of the meniscus.
  • Explain and avoid parallax error.

Before you start

  • Count in ones, fives and tens on a scale.

Materials

  • Water, coloured water and cooking oil

Equipment

  • 100 mL measuring cylinder marked in 1 mL divisions
  • Dropper to adjust the volume

Procedure

  1. Choose a sample. Move your eye level with the meniscus.
  2. Use the magnifier to find the mark at the bottom of the meniscus and move the reading slider to it.
  3. Record the correct reading of each sample.
  4. Look from above and from below and see how the line of sight hits a different mark.

How this simulation is simplified

  • The cylinder stands on a level bench.
  • Looking from above or below shifts the apparent reading by 2 mL.