Per Teodor Cleve

Per Cleve was a scientist from Sweden.

He loved to study the world. He found new parts of nature in rocks. He found two new parts named holmium and thulium.

He also studied tiny life in the water. He looked at small things called plankton. He even found helium in a special rock. His work helps us understand our earth. He was a great teacher, too.

Per Teodor Cleve was a famous scientist from Sweden.

He studied many things like chemistry and biology. He also studied rocks and the ocean. Cleve is best known for finding new chemical elements. In 1879, he found holmium and thulium. He found them while looking at a sample of erbium oxide. He saw a brown substance and a green substance in the sample. These were the new elements.

Cleve also helped find helium in a mineral called cleveite. This mineral was named after him.

Later in life, Cleve focused on biology. He studied tiny life in the water. This includes plankton and algae. He also studied diatoms, which are tiny organisms with shells. Cleve used these fossils to find the age of old earth deposits. He was a great teacher at Uppsala University. One of his students was Ellen Fries. She was the first woman in Sweden to earn a PhD. Cleve supported women's equality. He won the Davy Medal twice for his hard work. He died in 1905 at age 65.

Per Teodor Cleve was a very busy scientist from Sweden.

He studied many different parts of the natural world. He worked in chemistry, biology, and the study of rocks. He even studied the deep ocean. Cleve is most famous for finding new chemical elements. These are the basic building blocks of everything around us. His work helped us understand how matter is made. He was a member of the Royal Swedish Academy of Sciences starting in 1871.

Cleve found new elements by looking very closely at samples. In 1879, he looked at a sample called erbium oxide. He wanted to remove the impurities from this sample. While he did this, he found a brown substance. He also found a green substance. These were actually two new elements called holmium and thulium.

Later, in 1895, he and Abraham Langlet found helium in a mineral. This mineral was named cleveite to honor him. He also proved that scandium was an element that a scientist named Dmitri Mendeleev had predicted.

Cleve spent much of his life at Uppsala University. He was born in Stockholm in 1840. He earned his Bachelor of Science degree in 1863. He then earned his PhD in 1868. He became an assistant professor of chemistry at the university. Later, he became a professor of general and agricultural chemistry. He even served as the chair of chemistry at Uppsala starting in 1874. He was also the president of the Nobel Committee for Chemistry.

In 1890, Cleve changed his focus to biology. He wanted to learn about tiny living things in the water. He studied algae, plankton, and diatoms. Diatoms are tiny organisms with shells.

He used diatom fossils to find the age of old earth deposits. He even went on a Swedish expedition to Spitsbergen in 1898. On this trip, he found many new species of tiny sea life. He wrote a very important book about the ocean.

Cleve was also a kind and helpful teacher. He supported women's equality in science. One of his students was Ellen Fries. She was the first woman in Sweden to earn a PhD. His teaching helped many other scientists. For example, his student Svante Arrhenius later won a Nobel Prize. Cleve won the Davy Medal twice, in 1894 and 1904. He died in 1905 at the age of 65. His family also included many talented people, like his daughter Agnes, who was a modern artist.

Per Teodor Cleve was a highly versatile Swedish scientist. He made major contributions to chemistry, biology, mineralogy, and oceanography.

Born in Stockholm in 1840, he grew up with a strong interest in natural history. He eventually became a professor at Uppsala University. His work helped define how we understand chemical elements and tiny marine organisms. Cleve's career spanned several different scientific fields throughout the 19th century.

Cleve is most famous for his work with chemical elements. In 1879, he examined a sample of erbium oxide. He was attempting to remove impurities from this substance. During this process, he identified a brown substance and a green substance. These were actually two new elements: holmium and thulium.

He also proved that scandium was an element. This element had been predicted by the scientist Dmitri Mendeleev as "eka-boron." In 1895, Cleve and Abraham Langlet discovered helium within a mineral named cleveite.

His chemical research involved complex theories and precise measurements. In 1874, he proposed that didymium was not one element, but two. This theory remained unproven until 1885. That year, Carl Auer von Welsbach discovered the elements neodymium and praseodymium. Cleve also studied the properties of other elements. He determined that thorium was a quadrivalent element. He also found that lanthanum was trivalent. These specific findings were initially met with doubt by other scientists.

After 1890, Cleve shifted his primary focus toward biology. He became interested in studying freshwater algae, plankton, and diatoms. Diatoms are microscopic organisms that often leave behind fossils. Cleve developed a method to use these diatom fossils for dating. He could determine the age and order of glacial and postglacial deposits. This helped scientists understand the history of Earth's changing climate. He also wrote a seminal text on the field of oceanography.

Cleve participated in significant scientific expeditions during his life. In 1898, he joined a Swedish expedition to Spitsbergen. During this mission, he discovered many new species of marine life. These included species of spumellarians, nassellarians, and phaeodarians. He worked with Johann Diedrich Möller to distribute microscope slides of diatoms. This work helped other researchers study these tiny organisms. His studies of Atlantic plankton organisms were also published in 1900.

As an educator, Cleve had a lasting impact on the scientific community. He taught at the University of Uppsala and the Royal Institute of Technology. He was a supporter of women's equality in academia. One of his notable students was Ellen Fries. She was the first Swedish woman to earn a PhD. Another famous student was Svante Arrhenius, who later won a Nobel Prize. Cleve also served as the president of the Nobel Committee for Chemistry.

Cleve received several honors for his many scientific achievements. He joined the Royal Swedish Academy of Sciences in 1871. He was awarded the Davy Medal twice, once in 1894 and again in 1904. His family was also full of talented individuals. His daughter Agnes Cleve-Jonand became a pioneer of Modernism in Swedish art. His daughter Astrid Maria Cleve became a botanist. Cleve died in Uppsala in 1905 at the age of 65 after suffering from pleurisy.