For this Year 6 science project you will need:

What to do:

  1. Fill the jars with hot water.
  2. Add as much baking soda to each jar as will dissolve.
  3. Mix well to dissolve the baking soda.
  4. Dip one end of the wool in each jar, making sure the ends are weighed down by the paperclips.
  5. Place the saucer or plate between the jars.
  6. Let the thread hang between the jars, over the saucer.
  7. Leave for 2-3 weeks.

What happens:

A white stalactite grows down from the wool and a stalagmite grows up from the saucer.

Why It Happens:

The baking soda mix is carried up through the wool. This is called capillary action. The mix then drips onto the saucer. Over the days, the dripping water evaporates, leaving a little of the baking soda behind. These bits of baking soda make a tiny stalactite and stalagmite. After a few months, these will join to make a single column like the ones you might see in a cave.

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