History 5 Lesson 125

Light Bulb

The arc lamp required too much power. Edison tried 3,000 different versions of the light bulb. He tested 6,000 kinds of plant matter for filaments. Edison invented the incandescent bulbs in 1879. Incandescent lights are glass tubes with metal filaments inside. Filament heart-resistant tungsten. The metal “evaporates”. The vacuum increases filament lifespan. Inert gas reduces evaporation, it powers bulbs to scatter light, it lights up dark areas cheaply. They replaced gas lamps in theaters. Edison rapidly expanded his power grid in the US. New models have the same light, less cost. Good light improves appearance in mirrors. 

Cash Register

James Ritty was born in 1836 in Ohio. He opened a saloon in 1878. Ritty’s employees were stealing. He gained inspiration while on a boat ride to Rurope. Ritty invented the cash register in 1879. Cash registers ring up transactions. It guards the cash drawer. It corrects change calculated for customers. Produces two sets of documentation. It reduces the cashier skill set, reduces errors, and prevents theft. Ritty’s machine “registered” each transaction audibly. National cash Register added paper receipts Improved marking by identifying customer hot button: theft. Established American Selling Force. Controlled 95% of markert by 1911. 


Warren Johson was born in Vermont in 1847. He became a science professor when 34. Johnson invented the thermostat in 1883. Thermostats regulate temperature. Used with air conditioning systems. Two metals expand at different rates. Mercury switches company founded in 1885. Developed a multi-Zone thermostat in 1884. It was used in egg incubators.

Steam Turbine

Charles Parsons was born in England in 1854. Assisted his father in astronomical work. Learned shipbuilding and weapons manufacturing. He then moved into electrical machinery in 1884. Inspired by contemporary design invented the steam turbine in 1884. Steam turbines convert heat into rotation. Multi-stage turbines are efficient. Power plants produce steam. The blades extract heat and lower the steam’s pressure. Complex blade designs. Makes bulk power productions cheap. Parsons founded a company to manufacture the turbines. Westinyhouse became interested. 

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