Liquid Heat Capacity
An object’s heat capacity describes the amount of heat required to change the temperature of that object by a certain amount. Specific heat is the amount of heat required to change the temperature of a substance by one degree (generally °C).
Liquids absorb heat in different ways. The temperature change in a particular liquid heated by conduction may not be the same trend of temperature change for the same liquid heated by radiation.
Watermelon Phone Charger
Watermelons can be used to power electronic devices, including being used to charge your smartphone. If you partially submerge a medium-sized watermelon in a bath of salty ice water and plug your smartphone charger into the rind, it’s supposed to generate enough electricity to charge your phone. It starts to work by adding more ice and more salt.
Human Conductor of Electricity
Electrons are relatively free to jump from one atom to the next, and they’re attracted to some materials more than others. When you rub a balloon on your hair, electrons from your hair jump over to the balloon and stay there. The inside of a fluorescent tube is coated with a white material made up of phosphors. If you bombard phosphors with ultraviolet light, they re-emit visible light. In normal operation, the fluorescent tube is connected to a source of electrical current. The current supplies electrons that slam around inside the tube. Inside the tube there is also mercury vapor. When electrons collide with the mercury vapor, they cause the vapor to emit ultraviolet light, which hits the phosphors and the tube lights up. Bringing a negatively charged balloon near a fluorescent tube stirs up the electrons in the mercury vapor. This produces an electrical current, which excites the mercury atoms. The excited mercury atoms emit ultraviolet light and cause the phosphors to glow. When a spark jumps, you get a big release of energy and a correspondingly brighter glow.