Density
Properties of Matter

Salty Straws

Enrichment Activity for 5-11 11-14


What you need

  • Two small cups tea or coffee
  • Two straws
  • Salt
  • A friend

Instructions

  1. Pour equal amounts  tea or coffee into two small cups, with the help of a friend if you need it
  2. Add enough salt to one cup so that no more salt can dissolve
  3. Place a straw into each cup, put a finger over the end of each straw and lift the straws out
  4. The liquid should be lower in the straw from the salty tea or coffee

Results and Explanation

The salt increases the density of the liquid, which means less of it is picked up when the straws are lifted.

Density
appears in the relation m=ρV
IOP DOMAINS Physics CPD programme

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