Three Popular Inventions (the 9-th grade)

The television

The invention with the biggest impact was probably the television. It was invented by a Scottish man, John Logie Baird. The first televised pictures were sent over a short distance in 1924, and his invention was formally demonstrated at the Royal Institute two years later. The pictures on the screen were not clear, but the viewers could see that they were human faces, and they could see their eyes opening and closing. In 1928, images were sent from Britain to America, and later, to a ship 1,500 miles out to sea. In the same year, the first colour images were sent. The first ‘seeing-in sets’ were sold that same year. For £25 (£1000 in today’s money), people in their homes could watch moving images that were sent from a broadcasting station.

1. When television images were first transmitted, viewers didn’t know exactly what the image was.

The television

The invention with the biggest impact was probably the television. It was invented by a Scottish man, John Logie Baird. The first televised pictures were sent over a short distance in 1924, and his invention was formally demonstrated at the Royal Institute two years later. The pictures on the screen were not clear, but the viewers could see that they were human faces, and they could see their eyes opening and closing. In 1928, images were sent from Britain to America, and later, to a ship 1,500 miles out to sea. In the same year, the first colour images were sent. The first ‘seeing-in sets’ were sold that same year. For £25 (£1000 in today’s money), people in their homes could watch moving images that were sent from a broadcasting station.

2. The television was demonstrated at the Royal Institute in 1926.

The television

The invention with the biggest impact was probably the television. It was invented by a Scottish man, John Logie Baird. The first televised pictures were sent over a short distance in 1924, and his invention was formally demonstrated at the Royal Institute two years later. The pictures on the screen were not clear, but the viewers could see that they were human faces, and they could see their eyes opening and closing. In 1928, images were sent from Britain to America, and later, to a ship 1,500 miles out to sea. In the same year, the first colour images were sent. The first ‘seeing-in sets’ were sold that same year. For £25 (£1000 in today’s money), people in their homes could watch moving images that were sent from a broadcasting station.

3. Colour images were not possible until after the 1920s.

The television

The invention with the biggest impact was probably the television. It was invented by a Scottish man, John Logie Baird. The first televised pictures were sent over a short distance in 1924, and his invention was formally demonstrated at the Royal Institute two years later. The pictures on the screen were not clear, but the viewers could see that they were human faces, and they could see their eyes opening and closing. In 1928, images were sent from Britain to America, and later, to a ship 1,500 miles out to sea. In the same year, the first colour images were sent. The first ‘seeing-in sets’ were sold that same year. For £25 (£1000 in today’s money), people in their homes could watch moving images that were sent from a broadcasting station.

4. Television images were first sent across the Atlantic Ocean in 1928.

The television

The invention with the biggest impact was probably the television. It was invented by a Scottish man, John Logie Baird. The first televised pictures were sent over a short distance in 1924, and his invention was formally demonstrated at the Royal Institute two years later. The pictures on the screen were not clear, but the viewers could see that they were human faces, and they could see their eyes opening and closing. In 1928, images were sent from Britain to America, and later, to a ship 1,500 miles out to sea. In the same year, the first colour images were sent. The first ‘seeing-in sets’ were sold that same year. For £25 (£1000 in today’s money), people in their homes could watch moving images that were sent from a broadcasting station.

5. People could buy television sets in the 1920s.

The fridge

Another invention that became popular in the 1920s was the home refrigerator. People used different ways to keep food cool and fresh long before the 1900s, but home fridges weren’t invented until 1913 in the USA. Home fridges became very popular in the USA in the 1920s. Sales of the popular ‘Frigidaire’ model increased from 5,000 in 1921 to 750,000 in 1926. British people were less interested in fridges than Americans. They thought that they were unnecessary because the weather in Britain was cooler. But fridges were heavily advertised, and their advantages were described in detail. Soon, more fridges were sold, and the price decreased.

6. Harrison's first mechanical ice machine first appeared in 1854. 

The fridge

Another invention that became popular in the 1920s was the home refrigerator. People used different ways to keep food cool and fresh long before the 1900s, but home fridges weren’t invented until 1913 in the USA. Home fridges became very popular in the USA in the 1920s. Sales of the popular ‘Frigidaire’ model increased from 5,000 in 1921 to 750,000 in 1926. British people were less interested in fridges than Americans. They thought that they were unnecessary because the weather in Britain was cooler. But fridges were heavily advertised, and their advantages were described in detail. Soon, more fridges were sold, and the price decreased.

7. Home refrigerators were invented in the 1920s.

The fridge

Another invention that became popular in the 1920s was the home refrigerator. People used different ways to keep food cool and fresh long before the 1900s, but home fridges weren’t invented until 1913 in the USA. Home fridges became very popular in the USA in the 1920s. Sales of the popular ‘Frigidaire’ model increased from 5,000 in 1921 to 750,000 in 1926. British people were less interested in fridges than Americans. They thought that they were unnecessary because the weather in Britain was cooler. But fridges were heavily advertised, and their advantages were described in detail. Soon, more fridges were sold, and the price decreased.

8. Fridges became popular in the USA before they were popular in the UK.

The polygraph

Another interesting invention of the 1920s was the polygraph, or lie detector. It was invented in 1921 by a Californian policeman, John Larson. He used the ideas of other psychologists to make a machine that measured people’s heart rate, breathing and blood pressure while they were asked questions. The experts believed that sudden changes in these measurements showed that someone was lying. Although this invention is well-known, it can’t really detect lies. Marston tried to use measurements from his polygraph in a court case in 1923, but they weren’t accepted as evidence and never have been since then. However, polygraphs are still used by some police forces and the FBI because many people believe they work, so they tell the truth to avoid the machine.

9. Some psychologists helped John Larson to build his invention.

The polygraph

Another interesting invention of the 1920s was the polygraph, or lie detector. It was invented in 1921 by a Californian policeman, John Larson. He used the ideas of other psychologists to make a machine that measured people’s heart rate, breathing and blood pressure while they were asked questions. The experts believed that sudden changes in these measurements showed that someone was lying. Although this invention is well-known, it can’t really detect lies. Marston tried to use measurements from his polygraph in a court case in 1923, but they weren’t accepted as evidence and never have been since then. However, polygraphs are still used by some police forces and the FBI because many people believe they work, so they tell the truth to avoid the machine.

10. The idea for the polygraph test came from William Marston.

Another interesting invention of the 1920s was the polygraph, or lie detector. It was invented in 1921 by a Californian policeman, John Larson. He used the ideas of other psychologists to make a machine that measured people’s heart rate, breathing and blood pressure while they were asked questions. The experts believed that sudden changes in these measurements showed that someone was lying. Although this invention is well-known, it can’t really detect lies. Marston tried to use measurements from his polygraph in a court case in 1923, but they weren’t accepted as evidence and never have been since then. However, polygraphs are still used by some police forces and the FBI because many people believe they work, so they tell the truth to avoid the machine.

11. On some occasions, lie detectors have been used as evidence in court.

Another interesting invention of the 1920s was the polygraph, or lie detector. It was invented in 1921 by a Californian policeman, John Larson. He used the ideas of other psychologists to make a machine that measured people’s heart rate, breathing and blood pressure while they were asked questions. The experts believed that sudden changes in these measurements showed that someone was lying. Although this invention is well-known, it can’t really detect lies. Marston tried to use measurements from his polygraph in a court case in 1923, but they weren’t accepted as evidence and never have been since then. However, polygraphs are still used by some police forces and the FBI because many people believe they work, so they tell the truth to avoid the machine.

12. Today, lie detectors are never used by the police.