Low Temperature Stirling Engine - Heat Motor Science Model - Perfect Dad/Boy Gift

Education toys idea for science learning. No battery required. A special gift for friends , family...
WALKING BEAM BOIL WATER STIRLING ENGINE
https://www.etsy.com/shop/jajhobby .
The top plate is made from acrylic , therefore all the moving parts are visible.
Place this Stirling Engine on a cup of hot water / hot coffee & it may needs some time to start. The time is depends on the heat source given & is generally within 30 seconds to 2 minutes...
The engine won't start by itself, but given a little push in the proper direction (strong enough to coast the parts over for several cycles), the engine will take off and continue running on its own.

video :https://www.youtube.com/watch?v=HOrJoFKj2kw

Specification:-
Weight :250g
Sizes : 120mm x 120mm x 160mm
Material : Top -Arcylic Plate
Diaplacer - polyfoam
Bottom & others - aluminium