Lower Secondary Science Online Lesson (Term 1 Week 1 – 3):
Task 1:
1) Scientists have created all the elements beyond element 92.
Find out how they have been made.
Answer: The way these elements are made are all thanks to the
effort of Ernest Lawrence at the University of California at
Berkeley, who invented the cyclotron in the early 1930s. The
cyclotron could speed up protons or ions (charged atoms) of other
elements to high energies and fire them at atoms of uranium (or any
other element) like machine-gun bullets at a target. In the resulting
nuclear reaction, maybe some protons from the bullet nuclei would
stick in some of the target nuclei, thereby transforming them into
nuclei of higher atomic numbers. This process is known as nuclear
reactions, shooting light atoms at heavy atoms has turned out to be
the main method for producing even heavier atoms far beyond
uranium which is also how elements beyond element 92 are made.
2) It is said that the stars are the ‘element factories of the
universe’, that is, stars make the elements. Do some research
and find out how the stars make elements.
Answer: Stars make elements by converting matter into energy as
they make new elements by nuclear fusion; an example of this is
when 4 hydrogen atoms are combined to make 1 Helium atom. Next,
after the stars actually do run out of these hydrogen atoms, they
use the helium atoms which were made, to be combined together
with more helium atoms to create heavier elements, and this is how
most of the other elements are made; such as carbon, nitrogen,
oxygen and many other elements.
3) Choose an element and research the following information about it:
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When it was discovered
by whom it was discovered
how it is found in nature
its properties and uses.
I have decided to choose the element hydrogen. The element hydrogen
is the chemical element with an atomic number of 1, and it is the lightest
and most abundant element. Hydrogen was first generated and
described by Paracelsus, who was T. Von Hohenheim. He
reacted strong acids with metals to produce it, however, credit
for the discovery of hydrogen is often given to Henry
Cavendish ,who produced it, discovered that it actually burned
and produced water upon combustion, and also proposed it
was a unique element, which was done in 1776. Another person
who had a part to play was Robert Boyle, who dissolved iron in diluted
hydrochloric acid, and produced hydrogen. This passage answers
when hydrogen was discovered and whom it was discovered by.
Hydrogen is found as a colourless and odourless gas formed by
diatomic elements. The atom of the hydrogen is formed by one
electron and a nucleus with one unit of positive charge.
Hydrogen itself is also one of the main compounds of water and
of almost all the other organic matter. It is also widely spread
out not only in Earth but also in the whole universe. This
passage then answers about how hydrogen is found in nature.
The most important use of hydrogen is the ammonia synthesis.
The use of hydrogen is extending quickly in fuel refinement,
like the breaking down by hydrogen and in sulphur elimination.
Huge quantities of hydrogen are consumed in the catalytic
hydrogenation of unsaturated vegetable oils to obtain solid fat.
Hydrogenation is also used in the manufacture of organic
chemical products. Huge quantities of hydrogen are used as
rocket fuels, in combination with oxygen or fluor, and as a
rocket propellent propelled by nuclear energy.
Hydrogen can be burned in internal combustion engines.
Hydrogen fuel cells are being looked into as a way to provide
power and research is being conducted on hydrogen as a
possible major future fuel. For instance it can be converted to
and from electricity from bio-fuels, from and into natural gas
and diesel fuel, theoretically with no emissions of either CO2 or
toxic chemicals. This passage then answers about the usage of
hydrogen.
Done By: Gordon Koh (2i115)
17/01/2011