Science: Unit 4, Topics 4-5 Flashcards
Light energy (solar) into electricity?
Solar panels, photo-voltaic cells
Electricity into light (solar)?
Light bulbs
Thermal (heat) energy into electricity?
Thermocouple
Electricity into thermal energy (heat)
Hair dryer, oven, heater
Kinetic (motion) energy into electricity?
quartz-vibrations
What is an anode?
Negatively charged electrodes that leave the cell
What is a cathode?
Positively charged electrodes that enter the cell
What is an electrolyte?
A substance that conducts an electric current, and in which the electrodes are placed
Which way do electrons flow in a wet cell?
From the cathode to the anode
Primary vs Secondary Cells
Primary Cell: A cell that cannot be recharged. The size of the cell determines how long it will last.
Secondary Cell: A cell that is rechargeable and uses chemical reactions that can be reversed.
Wet vs Dry Cells
Wet Cells: Has a liquid electrolyte.
Dry Cells: Has paste, plastic, or a ceramic solid electrolyte.
Types of batteries?
Zinc Carbon: Flashlights, portable radios, CD players
Alkaline: Flashlights, portable radios, CD players
Zinc Air: Calculators, hearing aids, watches
Lead Acid: Cars, motorbikes. snowmobiles, golf carts
Nickel Cadmium: Electric shavers, laptop computers, power tools, portable TVs
Nickel-Metal Hydride: Cameras, laptops, cells phones, hand tools, toys
How does an electrochemical wet cell work?
When the cathode and anode metal strips are put into an electrolyte solution, the electrons will move from the cathode to the anode through a conducting wire and will light the light source. The circuit is completed by the movement of charged metal ions in the electrolyte.
How do Ballard fuel cells work?
They combine hydrogen and oxygen without it combusting. Electricity, heat, and pure water are the only by-products of the fuel cell’s reactions, and unlike any other electrochemical cells, fuel cells are not limited by the supply of chemicals inside them. And as long as the appropriate fuel is being supplied, the cell will continue to produce electricity
Thermocouples and examples?
A thermocouple is a loop of two wires made of different types of metals. The wires are wrapped together at both ends (junctions) when one junction is heated, a small electric current is produced, and if the temperature difference between the junctions is increased, the current will also increase. They are used in furnaces, hot water heaters, electric ovens
