When high energy radiation strikes the Earth from space, it’s called cosmic rays. To be accurate, a cosmic ray is not like a ray of sunshine, but rather is a super-fast particle slinging through space. Think of throwing a grain of sand at a 100 mph… and that’s what we call a ‘cosmic ray’. Build your own electroscope with this video!
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Materials:
- Clean glass jar with a lid
- Wire coat hanger and sand paper
- Aluminum foil
- Vice grips or a hacksaw
- Scissors
- Balloon or other object to create a static charge
- Hot glue gun (optional)
Download Student Worksheet & Exercises
Troubleshooting: This device is also known as an electroscope, and its job is to detect static charges, whether positive or negative. The easiest way to make sure your electroscope is working is to rub your head with a balloon and bring it near the foil ball on top – the foil “leaves” inside the jar should spread apart into a V-shape.
Exercises
- How does this detector work?
- Do all particles leave the same trail?
- What happens when the magnet is brought close to the jar?
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My husband and son created this. They said that the trick to getting it to work was in step 1 – snip the corners on both sides of the fold…snip so that the tiniest bit of alum foil is left. this allowed the foil strips to move more easily.
Be sure to thoroughly sand proper parts of the coat hanger. You want to only sand the coat hanger where the two pieces of aluminum foil come in contact with it.
Sometimes the foil can be too heavy. We recommend using really thin aluminum foil, such as the type you find at “dollar stores”.
Also, when you hold your electroscope, only touch the glass jar, but not the metal lid. Touching the lid can cause electrons to dissipate to your hand.
Hi I have a question. I tried making this but it didn’t work do you know what might help?
From Jessie.