|This week's activity can be found in the CIEC resource 'Runny Liquids' which can be downloaded from http://www.ciec.org.uk/resources/runny-liquids.html|
- Introduce the problem which is that children need to investigate the 'runniness' or viscosity of a selection of liquids (perhaps using the letter on page 19 of 'Runny Liquids').
- Give the children a range of liquids to explore. Can they predict and rank, which is the thickest and which is thinnest?
|Sheet for children to record their predictions of the comparative viscocity of various liquids|
- Explain that, as scientists, we need to collect some data, to see if our predictions are correct. Present children with a range of equipment (see suggestions below). Can the pupils come up with a test to measure how thick or thin the liquids are?
- Allow children to design a test and have a go. (Possible suggestions for tests: you could measure the time taken for a marble to drop through a set volume of liquid or time how long a spoonful of liquid takes to run down an angled tray).
|Children from Greengates School Stockton on Tees measuring the viscocity of a liquid.|
- Mini plenary discussions: What test did you come up with? What measurements did you take to compare the liquids? How can you make your tests fair? (Tip: Demonstrate an unfair test, using different volumes of liquids and discuss how it could be improved)
- Give children the opportunity to evaluate and improve tests. (Tip: If the volume of liquid chosen is too small, the range of results will be limited, so children could repeat with a larger volume and explore if this give a wider more accurate spread of results)
- Test all liquids and record results.
|Table for children to record their results|
- Collate class data. This could perhpas be done during a maths lesson, taking an average of all of the results.
- Look for patterns and draw conclusions. Which was the thinnest and which was the thickest liquid? Did all the groups get the same results/ order of liquids? Why not? Have a class discussion regarding any differences and discuss what was tricky. (Tip: Use two different brands of one liquid, or different sizes of funnel or container so that a variable has been introduced that was not controlled. Can anyone spot something was not fair?)
- Children present their data, draw conclusions and suggest improvements.
- Refer back to the problem and the predictions. Were they right? Which liquids flow well?
- Relate to industry and everyday life. Discuss applications where viscosity is important (Food products like chocolate and ketchup, medicines, syrups, body lotions and glues). Discuss how might viscosity be measured in industry?
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
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, based on evidence, for the particular use of everyday materials'
'Find out about how chemists create new materials'
Opporunities for working scientifically
As they learn about the runniness, or viscosity, of liquids, children can work scientifically by
Designing a fair test and controlling variables.
Making systematic observations
Taking accurate measurements
Looking for patterns
Drawing simple conclusions
What would happen if we pour 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.