Human Reproductive System

Male Reproductive System The male reproductive system is illustrated to the right. Sperm are produced in the testes located in the scrotum. Normal body temperature is too hot thus is lethal to sperm so the testes are outside of the abdominal cavity where the temperature is about 2° C (3.6° F) lower. Note also that a woman’s body temperature is lowest around the time of ovulation to help...

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Type of Fertilization

Reproductive System Animals’ reproductive systems can be divided into the internal reproductive organs and the external genitalia. The gonads are the actual organs that produce the gametes. In the male, testes (singular = testis) produce sperm, and in the female, ovaries make eggs. In most animals, individuals are either definite males or definite females. However, in some species, individual organisms...

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Sun

What is the Sun? The Sun is what is known as a main sequence star; that is, a sphere composed primarily of the two gases hydrogen and helium such that certain conditions are met. The first condition is that it must have a mass falling within a certain range. Though debated, this range is generally accepted to be between approximately 1.4 x 1029 kg and 3.0 x 1032 kg. (This range is often describe...

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Planets

What is a Planet? The answer to this question is a highly controversial one. This has not always been the case, though. In fact, before 1978 the definition of a "planet" was not really necessary. Until that time a planet simply meant a body in orbit around the Sun, that reflected sunlight, and was not a planetary moon, asteroid, or comet. However, with the discovery of Pluto's moon Charon...

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Vision Defects

An image is focused exactly on the retina for a person with normal vision. The common defects of vision are : short-sightedness, long-sightedness, astigmatism, colour blindness and presbyopia.  Long-sightedness (Myopia) Light ray which enter a normal eye will be focus on the retina. When someone suffer from long-sightedness has the condition of unable to see the near objects clearly....

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Properties of Light

Light is a form of energy that travels at the speed 300,000,000 m/s. Approximately 7.5 rounds of the earth in 1 second. Light travels in a straight lines within the same medium (or medium with the same optical density). Light is reflected when it hits an opaque surface. Light is reflected when it travels from one transparent medium to another. REFLECTION OF LIGHT Light which falls on an opaque object...

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Physical and Chemical Changes

Physical changes are limited to changes that result in a difference in display without changing the composition. Some common changes (but not limited to) are:  ·         Texture ·         Color ·         Temperature ·         Shape Change...

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