Friday, August 17, 2018

Runny Liquids: testing viscosity

This week's activity can be found in the CIEC resource 'Runny Liquids' which can be downloaded from

In this activity children think about how the viscosity of a liquid affects its properties, and how this can be important for scientists in industry when they are creating different products.  The activities link strongly with the content knowledge for Year 5 'Materials' and there are also ample opportunities for working scientifically.  There are more details of curriculum links at the bottom of this post.

The Activity 'Runny Measuring': 
  • Children are given a selection of liquids to explore.  They are encouraged to predict which is the thickest and which is the thinnest.
Sheet for children to record their predictions of the comparative viscosity of various liquids
  • After talking about how scientists need to collect data children are invited to devise a way to test their predictions and to measure the relative viscosity of the liquids that they have been given. There are several suggestions for possible tests in the resource.
Children from Greengates School Stockton on Tees measuring the viscosity of a liquid.

  • Children are then supported to evaluate their own test, to consider how effective it was, whether it was fair, and whether it was accurate enough.  They are given time to refine their test and then to present their findings as clearly as possible.
Table for children to record their results

Suggested equipment:

 A range of liquids of varying viscosities (e.g. washing up liquid, mouthwash, conditioner), measuring cylinders, funnels, marbles, small beakers or yoghurt pots, paint trays, pipettes, syringes or spoons, lolly sticks, timers

Further Explorations:
  • What would happen if we poured the different liquids on top of each other? Would they mix up? Which liquid would sink to the bottom? 
  • Children could use their understanding of viscosity to explore if runniness is related to density by making their own density columns.

Links to the National Curriculum:
Y5 Properties and changes of materials

  • compare and group together everyday materials on the basis of their properties
  • give reasons for the particular use of everyday materials
  • find out how chemists create new materials
Working scientifically
  • Design a fair test 
  • Make systematic observations
  • Take accurate measurements
  • Recording data
  • Look for patterns