The age of the Earth can be accurately measured by measuring the content of radioactive uranium and lead in a meteorite. Since meteorites originated with the Solar System, determining their age would also determine the age of the Earth. Fragments of a meteorite from the Arizona crater were used for the calculations. 

Graduate student Clare Patterson was asked to measure the content of these substances.

The results of measuring the uranium content were always the same, but the amount of lead was different each time. Besides, there was too much of it. 

Patterson created the world's first "clean" room. In the end, he calculated the age of the Earth, which we all know now - 4.5 billion years. 

This was not the end of Patterson's achievements, but only the beginning.

Even the ancient Romans knew about the dangers of lead, about its harmful effects on the human organism. Lead poisoning can lead to infertility, anger attacks, and hallucinations. Nevertheless, they used lead pipes to bring water to their homes, and lead sweetened their wines. It was used because it was cheap, and people who were exposed to it the most were "expendable". 

Later, lead was used in the production of paints, toys, shoes, and light bulbs. In the 1920s, lead became an anti-knock agent in the production of petrol. Workers in the factories went crazy, jumped out of windows, saw hallucinations. But authoritative scientists have proved that the use of lead in gasoline is harmless. 

Patterson began research on measuring lead in the environment: in deep sea and shallow water, even in polar ice. Thus, he found out that the concentration of this metal in the environment was huge and harmful to humans, leading to chronic diseases. He published a scientific paper that started a thirty-year war between him and the leaders of the petrochemical industry. He struggled until lead was completely eliminated from the U.S. industry. 

This was the greatest victory in the field of ecology and health. In the few years after that, the average level of lead in the blood of children fell by 75%.

I strongly believe that Steve Jobs is one of these prominent people who has achieved not only wealth and success, but also wide-world respect and appreciation starting from the button for his diligence and persistence.

It is no doubt Steve Jobs has been brought up in poor and simple conditions with a few chances to get rid of the misery. He was adopted by his sister and got little attention and love in the childhood. 

Jobs admired his father’s craftsmanship as he really knew how to build and create anything. By the time he was ten, Jobs was deeply involved in electronics. Aber with his peers he was indifferent and had difficulties with making friends, becoming a socially awkward loner. Though his family was not well off, parents used all their savings to buy a new home, allowing the son to change schools. The new one was embedded in an environment that was even heavily populated with engineering families. The house was declared a historic site for Apple Computer. 

Later Steve has dropped the College because he did not want to spend the parents’ money on education he found as meaningless one. He started sleeping on the floor and returning bottles to get some money and applying for different jobs. 

Then Steve Jobs has managed to find people with the same goals and to try to develop different ideas for establishing their small business. He began to create new projects, make electronic devises and fix complicated computer mechanisms. Day after day he was moving to his dream to set up his own company and once it has come true.

Step by step Jobs was working harder and harder to become one of the most talented and genius people of the world having almost nothing in his pocket. I find this person with really extraordinary ideas. Steve Jobs has proved there is nothing impossible for the human beings.

 

should learn, once and for all, 'not to judge a book by its cover'.

But social scientists say that there are reasons why we judge people based on how they look. On a very basic level,judging people by their appearance means putting them quickly into categories. In the past, being able to do this was vitally important, and humans developed the he ability to judge other people in seconds. Susan Fiske, a professor of psychology and neuroscience at Princeton University, said that traditionally,most stereotypes are linked to judging whether a person looks dangerous or not. 'In prehistoric times, it was important to stay away from people who looked aggressive and dominant,'she said. One reason why our brains persist in using stereotypes, experts say, is that often they give us generally accurate

information, even if all the details aren't right. Ms Boyle's appearance, for example, accurately told us a lot about her, including her socio-economic level and lack of worldly experience.

People's enthusiasm for Susan Boyle, and for other underdogs who end up winning, is unlikely to stop us from stereotypingpeople. This maybe one of the reasons why,

although Ms Boyle expressed the hope that 'maybe this could teach them a lesson, or set an example,' she did begin to change her appearance,wearing make-up, dying her grey hair,and appearing in more stylish clothing.

The elder of two girls, she says she learned about climate change when she was eight, but that her parents were not climate activists.

 

Greta has Asperger's syndrome, a developmental disorder, and has described it as a gift and said being different is a "superpower".

 

In May 2018 Greta won a climate change essay competition in a local newspaper.

Three months later she started protesting in front of the Swedish parliament building, vowing to continue until the Swedish government met the carbon emissions target agreed by world leaders in Paris.

She held a sign that read "School Strike for Climate" and began regularly missing lessons to go on strike on Fridays, urging students around the world to join her.

Her protests went viral on social media and as support for her cause grew, other strikes started around the world, spreading with the hashtag #FridaysForFuture.

By December 2018, more than 20,000 students around the world had joined her in countries including Australia, the UK, Belgium, the US and Japan. She joined strikes around Europe, choosing to travel by train to limit her impact on the environment.

The teenager took the whole of 2019 off school to continue campaigning, to attend key climate conferences, and to join student protests around the world.

In September 2019, she travelled to New York to address a UN climate conference. Greta refuses to fly because of its environmental impact, so she made her way there on a racing yacht, in a journey that lasted two weeks.

When she arrived, millions of people around the world took part in a climate strike, underlining the scale of her influence. Addressing the conference, she blasted politicians for relying on young people for answers to climate change.

She said: "How dare you? I shouldn't be up here. I should be back in school on the other side of the ocean, yet you all come to us young people for hope. How dare you?"

She was named Time Magazine's Person of the Year.

'You have stolen my dreams and my childhood'

Greta says big governments and businesses around the world are not moving quickly enough to cut carbon emissions and has attacked world leaders for failing young people.

Initially, her protests focused on the Swedish government's climate targets, and she urged students around the world to make similar demands in their own countries.