Reverse Sand and Liquid Timers Set of 6
Reverse Sand and Liquid Timers Set of 6
Student's name
First and last name, and class if you know it. This goes on the pack label.
Pickup available at Mega DC – Tweed Heads South
Usually ready in 24 hours
The sand floats upwards - about $18.90 a timer
Six timers, 8.5 x 3 x 13.5cm each, in which the sand rises instead of falling. Run time varies between 2 and 3 minutes depending on temperature.
These are a teaching resource, not a toy. The supplier is explicit and so are we: they must be used with care, they may break if dropped from a height or used with force, they need adult supervision, and they must not be accessible to children without it. Each is filled with mineral oil. Recommended for children aged 3 years and older.
With that said, the reason to buy them is that they break an assumption. Every child knows sand falls. Watching it rise is the moment a five-year-old starts asking why - and that question is worth more than any worksheet on density.
The variable run time is a feature rather than a fault. Warmer oil runs faster, so the same timer is quicker in a sunny room than a cold one, which is a second experiment sitting inside the first.