Science Experiments

Michael Orji

Year 7 Sapphire

2nd November 2009

Newton's laws of motion

This laws describe the relationship between the forces acting on a body and the motion of that body. They were first compiled by Sir Isaac Newton in his work Philosophiæ Naturalis Principia Mathematica, first published on July 5, 1687. Newton used them to explain and investigate the motion of many physical objects and systems. For example, in the third volume of the text, Newton showed that these laws of motion, combined with his law of universal gravitation, explained Kepler's laws of planetary motion.

Newton's law of universal gravitation

Newton's law of universal gravitationstates that every object in this universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between their centres. This is a general physical law derived from empirical observations by what Newton called induction.[1] It is a part of classical mechanics and was formulated in Newton's work Philosophiae Naturalis Principia Mathematica ("the Principia"), first published on 5 July 1687. (When Newton's book was presented in 1686 to the Royal Society, Robert Hooke made a claim that Newton had obtained the inverse square law from.

The law of cell.

The cell was first discovered by Robert Hooke in 1665. He examined very thin slices of cork and saw a multitude of tiny pores that he remarked looked like the walled compartments of a honeycomb. Because of this association, Hooke called them cells, the name they still bear. However, Hooke did not know their real structure or function. [1] Hooke's description of these cells (which were actually non-living cell walls) was published in Micrographia.[2]. His cell observations gave no indication of the nucleus and other organelles found in most living cells.

The Boyle law.

A law of gases which states that at constant temperature the volume of a gas varies inversely with its pressure. This law, formulated by Robert Boyle (1627-1691), can also be stated thus: The product of the volume of a gas times the pressure exerted on it is a constant at a fixed temperature. The relation is approximately true for most gases, but is not followed at high pressure. The phenomenon was discovered independently by Edme Mariotte about 1650 and is known in Europe as Mariotte's law.

Solar energy is used for

1. Heating water, usually on rooftops of houses,
2. Heating greenhouses in cold climates for food crops,
3. Heating houses and buildings through walls and windows,
4. Generating electricity, usually through photovoltaic (PV) cells, again on rooftops. It can also be harnessed through solar towers, where hundreds of mirrors focus the rays onto a central point where a medium, for example, salt, is heated up to many hundreds of degrees. Another way is from solar farms of rows and rows of PV panels. All these generate electricity which is fed into the grid and used in households round the world.

In science, a "control group" is a group of test subjects that do not receive any of the experimental food/ gas/ poison/ bizarre additions to their environment, etc., that the

other groups in the test do get.)

For example, if you wanted to see the effects of feeding plutonium to hamsters,

(not recommended by the way)

you would get two groups of hamsters. One group is fed the plutonium, and all effects

would be observed. (none would be good)

What you need to show what happens to ordinary hamsters over the same period of time

is called a "control group".

This would be a (luckier) group of hamsters that were not fed the plutonium.

Then you could show the differences (considerable) of the resultant effects on the two groups.