1st Generation Pesticides: 1  2500 BC- farmers began using the toxic chemical sulfur to kill off pests from their crops. 2  15th century AD -a variety of chemicals such as, arsenic, hydrogen cyanide, mercury and lead were put to use. 17th century -nicotine sulfate, derived from tobacco leaves was discovered as an effective pesticide and ants were controlled with mixtures of honey and arsenic.
Cell phones communicate with nearby cell towers mainly through radiofrequency (RF) waves, a form of energy in the electromagnetic spectrum between FM radio waves and microwaves. Like FM radio waves, microwaves, visible light, and heat, they are forms of non-ionizing radiation.
The Basics of Brain Waves Brain waves are generated by the building blocks of your brain -- the individual cells called neurons. Neurons communicate with each other by electrical changes.We can actually see these electrical changes in the form of brain waves as shown in an EEG (electroencephalogram). Brain waves are measured in cycles per second (Hertz; Hz is the short form). We also talk about the frequency of brain wave activity. The lower the number of Hz, the slower the brain activity or the slower the frequency of the activity. Researchers in the 1930's and 40's identified several different types of brain waves. Traditionally, these fall into 4 types: