DIY spring elevator

Put your nitinol spring to the test!

Difficulty:
Danger:
Duration:
15 minutes
DIY spring elevator

Safety

  • Carefully review the general safety advice in the instruction book before starting the experiment.
  • Read the "Working with Batteries" section of the safety guidelines carefully before proceeding. Always disconnect the setup after finishing the experiment.
  • Avoid touching heated objects with bare hands.
  • Disassemble the setup after the experiment.

Step-by-step instructions

Let’s figure out the maximum load that our spring can lift! Rebuild the nitinol crane as shown in the picture. Then try to lift something that can be put in a bag, such as a few apples or a milk carton. If you are using a household item, check with your parents about using it first! Due to the shape memory effect, the spring returns to its original form when electrically heated, lifting the weight. Go ahead and test the lifting power of your nitinol crane!

Disposal

  • Dispose of solid waste together with household garbage.
  • Dispose of used batteries in accordance with local regulations.

Scientific description

Recall that nitinol is a shape-memory alloy. This means that a deformed object made of nitinol can return to its original shape when heated. Why does this happen?

The initial form of the nitinol object, in this case a coiled spring, was set at a very high temperature, which is preserved and “remembered” when it cools. When you stretch the spring, you change the structure of the cells and the arrangement of the particles within them. However, when the spring is heated, it becomes possible for its particles to move, and they return to their former places, thus restoring the spring’s original form.