|Arteries, Blood Cells, Chemical Change, Frequency, Genes, Molecule, Nucleus, Prefixes, Radiation, Refraction
The aorta is the body's largest artery and receives blood from the pulmonary vein via the left ventricle. From there, blood is circulated through the rest of the body through smaller arteries called arterioles that branch out from the heart. Finally, blood is delivered to bodily tissues through capillaries.
Blood is created in bone marrow and is made up of cells suspended in liquid plasma. Red blood cells carry oxygen, white blood cells fight infection, and platelets are cell fragments that allow blood to clot.
During a chemical reaction molecules and atoms (reactants) are rearranged into new combinations that result in new kinds of atoms or molecules (products).
The rate of vibration of sound is called frequency and is measured in hertz (Hz). One hertz is one repetition per second and sounds with high frequency have a higher pitch than sounds with lower frequency. Humans can hear sounds in the range of 20 Hz to 20 kHz.
The gene is the base unit of inheritance and is contained within DNA. A gene may come in several varieties (alleles) and there are a pair of alleles for every gene. If the alleles are alike, a person is homozygous for that gene. If the alleles are different, heterozygous.
A molecule is the smallest multi-atom particle of an element or compound that can exist and still retain the characteristics of the element or compound. The molecules of elements consist of two or more similar atoms, the molecules of compounds consist of two or more different atoms.
Cells are classified into one of two groups based on whether or not they have a nucleus. Eukaryotic cells have a nucleus, prokaryotic cells do not have a nucleus and therefore have a less complex structure than eukaryotic cells.
A prefix is added to the base units of the metric system to indicate variations in size. Each prefix specifies a value relative to the base unit in a multiple of 10. Common prefixes are:
Radiation occurs when electromagnetic waves transmit heat. An example is the heat from the Sun as it travels to Earth.
Because different materials have different refractive indices, light changes speed when passing from one material to another. This causes the light to bend (refraction) at an angle that depends on the change in refractive index between the materials. The greater the difference, the higher the angle of refraction.