Science Revision 2 WIP
Science Revision 2 WIP
Variation and Inheritance
Adolescence is the transition from puberty to legal adulthood. Adolescence is when the growth spurt occurs. Changes in the brain and body also occur.
The menstrual cycle is the regular natural change that occurs in the female reproductive system (specifically the uterus and ovaries) that makes pregnancy possible. Up to 80% of women report having some symptoms during the one to two weeks prior to menstruation. Common symptoms include acne, tender breasts, bloating, feeling tired, irritability and mood changes.
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parents". Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction. There are two forms of reproduction: asexual and sexual.
Sexual reproduction typically requires the sexual interaction of two specialized organisms, called gametes, which contain half the number of chromosomes of normal cells and are created by meiosis, with typically a male fertilizing a female of the same species to create a fertilized zygote.
In asexual reproduction, an organism can reproduce without involvement with another organism.
Variation is a difference in features between individuals of the same species. Causes of variation can include where you were born, where you live and the genetics of your family: eye colour height etc.
A human can inherit many things: gender, eye colour, Inheritance can also be called heredity. In humans, eye colour is an example of an inherited characteristic: an individual might inherit the "brown-eye trait" from one of the parents. Inherited traits are controlled by genes and the complete set of genes within an organism's genome is called its genotype.
Living things can be classified into groups. The five main groups are Plants, Animals, Fungi, Monera and Protoctista. The Animals groups has many sub-groups, such as mammals, reptiles, arachnids, and crustaceans.
A moment is a turning force. When a force acts on something which has a pivot, it creates a turning force. Moment = force x perpendicular distance.
Types of force
Some types of force are: Gravitational, friction, magnetic, tension and air resistance.
Metals and Non-metals.
Metals are generally solid (with the exception of mercury). They are 75% of the periodic table. Some examples of metals are copper, zinc, gold, silver, tin and lead. Non-metals are element of the periodic table that are not solid, such as hydrogen and helium.
Chlorine - Chloride, Oxygen - Oxide, Sulphur - Sulphide etc. If Three or more elemants combine and one of them is oxygen, the ending will be 'ate'. Sodium + carbon + 3 oxygens = Sodium Carbon
Finally, when two identical elements combine, the name doesn't change at all.
There are 4 methods of separation: Filtration, Evaporation, Chromotography and Distillation. Filtration and evaporation are parts of the same method. In Rock Salt (A mixture of sand and salt) Filter paper is used to remove the sand and then (Because the salt dissolves in the water) evaporation is used to remove the water, leaving behind crystallized salt. Chromotpgraphy is dots of ink are put onto filter paper. Then a wick is cut from part of the paper and then a solvent washes the dyes through the paper. Finally, there are two types of distillation: Simple and fractional.
Simple distillation is used for separating liquids and solids. The liquid is heated and boils off. It's then cooled, condensed and collected, leaving the solid behind. Simple distillation is good for getting pure water from something like sea water or suspect tap water.
Fractional distillation is used for separating liquid mixtures. Different liquids have different boiling points. So when the 'wrong' liquid boils off, the fractionating column ensures if condenses back down, and only the liquid properly boiling at the temperature on the thermometer will make it to the top. When each liquid has boiled off, the temperature reading rises until the next fraction starts to boil off. This means the fractions are obtained pure.