Secret Message Writer
Introduction
Clean drinking water is essential for our health. Water containing bacteria or viruses can make us very sick. Unfortunately, not everybody has access to clean water from centralized water plants. However, nearly everybody nowadays has a smartphone! That’s why we developed a small device and an app which can be used with a smartphone to kill harmful bacteria in water. It could mean that people without a clean water supply can easily disinfect their drinking water and avoid getting sick.
About This Project
Imagine telling your friends about your latest science project: using a battery to make a light turn on. You might get some blank stares…sounds a little boring and basic, right? Now tell them you will do it with a potato! Yes, you can actually use fruits and vegetables as part of an electric power source! Batteries power many things around you, including cell phones, wireless video game controllers, and smoke detectors. In this science project, you will learn about the basics of battery science and use potatoes to make a simple battery to power a small light and a buzzer.
Full Article
Video
Material List
- 1 Cotton swab
- 1 Box of baking soda
- 1 Cup of water
- 1 Spoon
- 1 Sheet of white paper
- 1 Cup of blackberries
Instructions
- Mix 2 tablespoons of baking soda into one cup of water.
- Dip one end of a cotton swab into baking soda mixture and tap off any drips.
- Use the wet cotton swab to write a message in the center of the paper.
- Let the paper dry for about 10 minutes (until the writing disappears).
- To reveal the message, carefully rub the blackberry back and forth across paper.
How It Works
After you write on the paper with the baking soda and water mixture, the water evaporates leaving trails of baking soda crystals. The purple pigment from the blackberry reacts with the baking soda crystals, forming a new substance! Since a new substance is formed, this is a chemical change.
