You will need:
- White plastic disposable cup
- Pair of scissors
- 30-50cm length of thick string or twine
- Paper clip
- Large white serviette
- Elastic band
- Black marker pen.
Step 1: Use scissors to very carefully make a small hole in the bottom of your cup.
Step 2: Thread your string through the hole and tie the end on the outside of the cup to a paper clip. This will stop it from slipping through the hole.
Step 3: Wrap the serviette around the top of the cup to make your ghost’s body and secure with an elastic band. Draw eyes and an open, shrieking mouth for your ghost’s face.
Step 4: It’s time to get noisy! Grip the string inside the cup firmly and pull down, away from the cup. You can use a small piece of wet cloth to help your fingers slip smoothy down the string. Pull with one long movement or several tugs down the length of the string to change the sound. Don’t be spooked … it’s not a scream … it’s science!
STOP & THINK
What would happen to the sound if the cup used was bigger? Would it still be a shrieking ghost or more like a deep, cackling ghoul?
Sound is created by vibrations in the air which we sense using different parts of our ears. When you rub on the string it creates friction, causing vibrations which are amplified by the cup. Small plastic cups vibrate very quickly, making a high pitch shriek. Slower vibrations (like using a large cup or bucket) make lower pitched sounds.
NOTE: This is a Street Science Original Activity and may be used only in publications with written permission of the Street Science Executive. For non-profit use only.