What Is An Atom?

 

What Is An Atom?

  Famous Female Scientists

 These scientists are Caroline Herschel, Mary Anning, Ada Lovelace, Maria Mitchell, Mary Kingsley, Annie Cannon, Marie Curie, Louise Boyd, Gerty Cori, Irene Joliet-Curie, Helen Taussig, Margaret Mead, Barbara McClintock, Dame Kathleen Lonsdale, Ruth Wakefield, Grace Murray Hoppe, Rachel Carson, Chien-Shiung Wu, Mary Leakey, Gertrude Elion, Rosalind Franklin, Rosalyn Yalow, Stephanie Kwolek, Jewel Plummer Cobb, Dian Fossey, Jane Goodall, Ada Yonath, Jocelyn Bell Burnell, Ellen Ochoa.

• Caroline Herschel: – She was a German astronomer. She was the first woman to discover a comet and also to receive honorary membership into the Royal Society. In 1783, Caroline Herschel discovered an open cluster which is known as NGC 2360.
• Mary Anning: – She was an amateur paleontologist and a fossil collector. Anning is sometimes referred as ‘the greatest fossilist the world ever knew’.
• Ada Lovelace: – Ada Lovelace was an English mathematician. She is considered the first computer programmer. She is best known for her work on Charles Babbage’s proposed general-purpose computer.
• Maria Mitchell: – She was the first professional female astronomer of America. She discovered a comet in 1847.
• Mary Kingsley: – She was an English explorer and scientific writer. Kingsley traveled throughout the West Africa.
• Annie Cannon: – Annie Cannon was an American astronomer. She studied bright southern hemisphere stars.
• Marie Curie: – Marie Curie was the first woman to win a Noble prize and the first scientist to win this in two different fields physics and chemistry. She discovered Polonium and Radium.
• Louise Boyd: – Louise Boyd was an American explorer. She made her first trip to arctic in 1926. In 1955, she became the first woman to charter a private plane and fly across the North Pole.
• Gerty Cori: – Gerty Cori was a biochemist. She was the first American woman to win a Noble prize in science. She has done some research work on the metabolic mechanism.
• Irene Joliet-Curie: – She was the daughter of Pierre and Marie Curie. Both her parents were scientists. She served as a nurse radiographer during the World War I.
• Helen Taussig: – She was an American cardiologist. She is also credited with the development of the first successful treatment of ‘blue baby’ syndrome.
• Margaret Mead: – Margaret Mead was an anthropologist. In 1979, she was awarded the highest civilian order of the United States, the Presidential Medal of Freedom.
• Barbara McClintock: – She was an American scientist. She is best known for her discovery of mobile genetic elements. In 1983, she won the Noble Prize in Physiology.

Global warming

 

Global warming

2011-2020 was the warmest decade recorded, with global average temperature reaching 1.1°C above pre-industrial levels in 2019. Human-induced global warming is presently increasing at a rate of 0.2°C per decade.

An increase of 2°C compared to the temperature in pre-industrial times is associated with serious negative impacts on to the natural environment and human health and wellbeing, including a much higher risk that dangerous and possibly catastrophic changes in the global environment will occur.

For this reason, the international community has recognised the need to keep warming well below 2°C and pursue efforts to limit it to 1.5°C.

Greenhouse gases

The main driver of climate change is the greenhouse effect. Some gases in the Earth's atmosphere act a bit like the glass in a greenhouse, trapping the sun's heat and stopping it from leaking back into space and causing global warming.

Many of these greenhouse gases occur naturally, but human activities are increasing the concentrations of some of them in the atmosphere, in particular:

• carbon dioxide (CO2)
• methane
• nitrous oxide
• fluorinated gases

CO2 produced by human activities is the largest contributor to global warming. By 2020, its concentration in the atmosphere had risen to 48% above its pre-industrial level (before 1750).

Other greenhouse gases are emitted by human activities in smaller quantities. Methane is a more powerful greenhouse gas than CO2, but has a shorter atmospheric lifetime. Nitrous oxide, like CO2, is a long-lived greenhouse gas that accumulates in the atmosphere over decades to centuries. Non-greenhouse gas pollutants, including aerosols like soot, have different warming and cooling effects and are also associated with other issues such as poor air quality.

Natural causes, such as changes in solar radiation or volcanic activity are estimated to have contributed less than plus or minus 0.1°C to total warming between 1890 and 2010.

Causes for rising emissions

• Burning coal, oil and gas produces carbon dioxide and nitrous oxide.
• Cutting down forests (deforestation). Trees help to regulate the climate by absorbing CO2 from the atmosphere. When they are cut down, that beneficial effect is lost and the carbon stored in the trees is released into the atmosphere, adding to the greenhouse effect.
• Increasing livestock farming. Cows and sheep produce large amounts of methane when they digest their food.
• Fertilisers containing nitrogen produce nitrous oxide emissions.
• Fluorinated gases are emitted from equipment and products that use these gases. Such emissions have a very strong warming effect, up to 23 000 times greater than CO2.