# Understanding measuring cylinders

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**Demonstration**

An introduction to measuring cylinders, using known volumes of water from a rectangular box.

#### Apparatus and materials

Measuring cylinder, 250 ml

Measuring cylinder, 1000 ml

Rectangular Perspex box (10 cm x 10 cm x 11 cm)

Ruler

Marker pen

#### Health & Safety

#### Procedure

**a** Mark the Perspex box at a level of, say, 4 cm. Measure the width, breadth and depth of this volume, and calculate the volume (in cm^{3}).

**b** Fill the container with water to the marked level. Pour the water into the 250 ml measuring cylinder and note the level.

**c** The process may be repeated, different depths can be tried, and the larger measuring cylinder can be used. Pour water from measuring cylinder to measuring cylinder.

#### Teaching notes

**1** This is an introduction to the measuring cylinder. It is important the demonstration should not turn into a precise drill and thereby labour the discussion.

**2** A volume of water measured in the rectangular box is transferred into the measuring cylinder and the reading on the scale compared with the volume of water poured from the box. This is a way of calibrating a measuring cylinder from first principles by counting the cubes.

**3** The graduations on the measuring cylinder could be covered up with a paper scale, which could be filled in as volumes of liquid are poured from the box into the cylinder. Pouring from one cylinder into different sized cylinders will show the same reading providing no water has been lost!

**4** Piaget's theory on the conservation of volume of liquids by young students is valuable here. (Remember Piaget’s theories were based on different teaching methods so the ages at which students develop their cognition may vary.)

**5** Gases of course are not invariant in volume as they change containers.

*This experiment was safety-checked in July 2007*