4th grade technology

0) 01 What is technology?


Technology is what we make using our knowledge to make our lives simpler, and better. Cars, TV, and Buildings are all examples of technology.


we use cars for travel.

we use television for entertainement, learning, information, and education.

we use telephones to communicate with friends, family and also to conduct business, and to get things done.

we use computers to do research, to create documents, to create art, to control machines, to run cars, to run aeroplanes, to run hospitals, and to run companies in general.

Technology may have unexpected, or unanticipated harmful side affects. Some of the following will fall under this category:

Car Emissions

Cars emit smoke through their tail pipe which contains a gas called carbon dioxide. Excessive Carbon dioxide can cause "global warming" resulting in increased temparatures around the world include at the poles causing the ice caps at the poles to melt in summer.


we use fertilizers in our farms to produce more food. These fertilizers can drain into waterways and pollute waterways.


we use pesticides in our farms to kill harmful pests that would otherwise damage crops. The pesticides can get into the fruits and vegetables that we use. The pesticides can also run off into water streams.


Watching too much TV and not doing enough exercise can cause obesity in people.

4) 05 what is velcro?


Velcro is a material that we use technology to crate using two other technology materials called Polyester and Nylon.

Polyurethane is a type of rubber invented by a German inventor called Bayer in 1930s. Polyurethane is used, among other things, to make skating wheels

we spray pesticides on crops on a regular basis to kill harmful pests.

Insecticides are chemicals we use kill insects. Bug sprays is an example of insecticide.

Farmers use fertilizers to increase the yield, or output, or to produce more from their farm. Fertilizers are like food to plants. when the earth doesn't nutrients for the plants they don't grow well or produce enough fruits. This is why farmers use fertilzers to supply nutrients to plants so tha they can grow well.

Fertilizers can mix with water when it rains and become part of rivers and water supplies. These nutrients or chemicals can be harmful to fish and humans.

11) 12 what are emissions?


Smoke coming out of the tail pipes of cars is one example of emission. This contains a gas called carbon dioxide which is considered harmful as it will increase the temperature of earth over decades.

12) 13 what are x-rays?


x-rays is a type of invisible to the human eye light beam. x-rays are used by doctors to take pictures of bones and teeth and other hard material in our body covered by skin and flesh.

13) 14 who invented x-rays?


x-rays were invented by Wilhelm Roentzen, a German Physicist, in 1895. He received Nobel prize for that invention in 1901. He lived from 1845-1923.

For taking pictures of bones, teeth, and other hard parts of the body covered by skin and flesh.

Excessive exposure to x-rays can cause burns and cancer.

Doctors use x-rays to find out what is wrong with bones, teeth and other hard parts of the body covered by skin and flesh.

To see if they are broken or to see if they are bent

x-rays pass through soft material like tissue and blood vessels. As a result they don't show up on the x-ray film.

Magnetic Resonance Imaging. It uses magnetic fields to take pictures of soft tissues and blood vessels.

Magnetic Resonance Imaging. It uses magnetic fields to take pictures of soft tissues and blood vessels.

Optical fibers are tiny but long tubes that can carry light with them.

23) 23 what is a laser?


A laser is a concentrated beam of light.

Lasers are used to unclog arteries that carry blood in the heart to prevent heart attacks.

Lasers are used for eye surgeries.

Lasers are used for communicating messages through light.

Optical fibers are used in medicine for such things as key hole surgery.

Optical fibers are heavily used in carrying the electronic data through internet.

Doctors make a small incission in a patient similar to a key hole to insert an optical fiber or a small medical instrument and by using the light from the optical fiber and a camera they can conduct surgeries. This will save the patient from a large cut and prevents bleeding and allows faster recovery.

Yes. Eye sight can be corrected by using lasers using a surgical procedure.

By cutting away the excess fat collected in the blood vessels in the heart, lasers can help patients with clogged arteries.

Communication means exchanging messages.

US Post office

House telephone use electic wires to carry telephone messages.

Internet uses cable wires and optical fibers to carry messages.

Satelites use radio waves (kind of invisible light)to send messages to earth and to aeroplanes and ships

Voice from us is converted to an electrical signal in the telephone mouth piece

The electrical signal travels through the wire to a central telephone station and gets routed to the other telephone on the other side

The speaker converts the electrical signal back to voice which the person on the other end hears.

33) 33 what are satelites?


Satelites are man made machines that circle the earth. They help take pictures of the earth and carry telephone, internet, and tv data.

take pictures of the earth
carry telephone signals
carry tv signals
locate aeroplanes
locate ships
locate cars

Henry Ford in 1913 mass produced many cars in a factory so that they are cheap enough for lot of people to buy.

Wright brothers in 1903.

Starting with the first human flight by Wright brothers in 1903, it would make 100 years of flight in 2003. So we have been flying for more than a century.

Leonardo Da Vince (1452 to 1519) drew lots of designs for flying machines.

Leonardo da Vinci's studies, drawings, and never-finished inventions involving flight were revolutionary in design to say the least. It is debated whether da Vinci successfully flew using any of his machines, but even if they never left the ground in his time; modern day parachutes and helicopters are very similar to Leonardo's designs from hundreds of years ago. This is interesting because most of his work was not uncovered until the 19th century, after all the machines were reinvented. Leonardo's study of flight started with flapping-wing mechanisms, but after he discovered the futility of human powered and coordinated flight, he turned his eyes to the birds. He studied, watched, and dissected birds and bats, trying to discover what enables them to fly. After his writings on birds his research shifted to glider based flight, rather than further pursuing human powered wings, or the aerial screw (the ancestor of the helicopter).

Electricity travles very fast, almost instantaneously. So messages sent through telephones travels much faster than paper. This allowed people to communicate faster. This has a big impact on early wars and also in saving lives as danger can be communicated that much faster for example of an approaching hurricane.


Yes, indeed. Most of the internet runs on optical fibers. There are optical fibers under sea beds that carry electronic messages between continents.

"Tele" means far and "vision" means sight. So television meant seeing from a distance.

Yes, for wireless communications lasers can be used. For example satelites can send communications using lasers.