The metric system is used for all scientific measurements, from the distance between galaxies to the size of an atom. The chart shown here provides an overview of some common categories of measurement and their units. The meter, abbreviated lowercase m, is the base unit of length. One meter is approximately 39.37 inches, a little more than a yard. Meter is spelled m-e-t-r-e outside the United States. The base unit for measuring mass is the gram, abbreviated lowercase g. One teaspoon of sugar has a mass of about 4 grams. The base unit for liquid volume is the liter, spelled l-i-t-r-e outside the United States. Liter can be abbreviated as lowercase l or capital L. Soda is sold in 2-liter bottles. The average adult human has about 5 liters of blood. The base unit for temperature is the degree Celsius, abbreviated with a degree symbol and capital C. The freezing point of water is 0 degrees Celsius; the boiling point of water is 100 degrees Celsius. For time, the base unit is the second, abbreviated lowercase s. Smaller or larger units of measurement are formed by multiplying the base unit by a power of ten and adding a prefix. Here are some prefixes for measurements that are smaller than the base unit: The prefix centi-, abbreviated lowercase c, is used for a measurement that is 10 to the minus 2nd, or one one-hundredth, times the base unit. For example, a centimeter is one one-hundredth of a meter. The prefix milli-, abbreviated lowercase m, is used for a measurement that is 10 to the minus 3rd, or one one-thousandth, times the base unit. For example, a milligram is one one-thousandth of a gram. The prefix micro-, abbreviated with the Greek symbol mu, is used for a measurement that is 10 to the minus 6th, or one one-millionth, times the base unit. The micrometer, abbreviated mu-m, is useful for measuring cells. For example, red blood cells are 7 to 8 micrometers in diameter. The prefix nano-, abbreviated lowercase n, is used for a measurement that is 10 to the minus 9th, or one one-billionth, times the base unit. The prefix pico-, abbreviated lowercase p, is used for a measurement that is 10 to the minus 12th, or one one-trillionth, times the base unit. Here are some prefixes for measurements that are larger than the base unit: Kilo-, abbreviated lowercase k, is used for a measurement that is 10 to the 3rd, or one thousand, times larger than the base unit. For example, a kilometer is one thousand times larger than a meter. The prefix mega-, abbreviated capital M, is used for a measurement that is 10 to the 6th, or one million, times larger than the base unit. The prefix giga-, abbreviated capital G, is used for a measurement that is 10 to the 9th, or one billion, times larger than the base unit. The prefix tera-, abbreviated capital T, is used for a measurement that is 10 to the 12th, or one trillion, times larger than the base unit. The prefix peta-, abbreviated capital P, is used for a measurement that is 10 to the 15th, or one quadrillion, times larger than the base unit. One exception to standard metric notation is the angstrom, abbreviated as a capital A with a circle over it. One angstrom is defined as 10 to the minus 10th meter. This unit is used by scientists because itís useful for measurements at the atomic level. For example, the diameter of one hydrogen atom is 1 angstrom.
Table of contents
- 1. Introduction to Biology2h 40m
- 2. Chemistry3h 40m
- 3. Water1h 26m
- 4. Biomolecules2h 23m
- 5. Cell Components2h 26m
- 6. The Membrane2h 31m
- 7. Energy and Metabolism2h 0m
- 8. Respiration2h 40m
- 9. Photosynthesis2h 49m
- 10. Cell Signaling59m
- 11. Cell Division2h 47m
- 12. Meiosis2h 0m
- 13. Mendelian Genetics4h 41m
- Introduction to Mendel's Experiments7m
- Genotype vs. Phenotype17m
- Punnett Squares13m
- Mendel's Experiments26m
- Mendel's Laws18m
- Monohybrid Crosses16m
- Test Crosses14m
- Dihybrid Crosses20m
- Punnett Square Probability26m
- Incomplete Dominance vs. Codominance20m
- Epistasis7m
- Non-Mendelian Genetics12m
- Pedigrees6m
- Autosomal Inheritance21m
- Sex-Linked Inheritance43m
- X-Inactivation9m
- 14. DNA Synthesis2h 27m
- 15. Gene Expression3h 20m
- 16. Regulation of Expression3h 31m
- Introduction to Regulation of Gene Expression13m
- Prokaryotic Gene Regulation via Operons27m
- The Lac Operon21m
- Glucose's Impact on Lac Operon25m
- The Trp Operon20m
- Review of the Lac Operon & Trp Operon11m
- Introduction to Eukaryotic Gene Regulation9m
- Eukaryotic Chromatin Modifications16m
- Eukaryotic Transcriptional Control22m
- Eukaryotic Post-Transcriptional Regulation28m
- Eukaryotic Post-Translational Regulation13m
- 17. Viruses37m
- 18. Biotechnology2h 58m
- 19. Genomics17m
- 20. Development1h 5m
- 21. Evolution3h 1m
- 22. Evolution of Populations3h 52m
- 23. Speciation1h 37m
- 24. History of Life on Earth2h 6m
- 25. Phylogeny2h 31m
- 26. Prokaryotes4h 59m
- 27. Protists1h 12m
- 28. Plants1h 22m
- 29. Fungi36m
- 30. Overview of Animals34m
- 31. Invertebrates1h 2m
- 32. Vertebrates50m
- 33. Plant Anatomy1h 3m
- 34. Vascular Plant Transport2m
- 35. Soil37m
- 36. Plant Reproduction47m
- 37. Plant Sensation and Response1h 9m
- 38. Animal Form and Function1h 19m
- 39. Digestive System10m
- 40. Circulatory System1h 57m
- 41. Immune System1h 12m
- 42. Osmoregulation and Excretion50m
- 43. Endocrine System4m
- 44. Animal Reproduction2m
- 45. Nervous System55m
- 46. Sensory Systems46m
- 47. Muscle Systems23m
- 48. Ecology3h 11m
- Introduction to Ecology20m
- Biogeography14m
- Earth's Climate Patterns50m
- Introduction to Terrestrial Biomes10m
- Terrestrial Biomes: Near Equator13m
- Terrestrial Biomes: Temperate Regions10m
- Terrestrial Biomes: Northern Regions15m
- Introduction to Aquatic Biomes27m
- Freshwater Aquatic Biomes14m
- Marine Aquatic Biomes13m
- 49. Animal Behavior28m
- 50. Population Ecology3h 41m
- Introduction to Population Ecology28m
- Population Sampling Methods23m
- Life History12m
- Population Demography17m
- Factors Limiting Population Growth14m
- Introduction to Population Growth Models22m
- Linear Population Growth6m
- Exponential Population Growth29m
- Logistic Population Growth32m
- r/K Selection10m
- The Human Population22m
- 51. Community Ecology2h 46m
- Introduction to Community Ecology2m
- Introduction to Community Interactions9m
- Community Interactions: Competition (-/-)38m
- Community Interactions: Exploitation (+/-)23m
- Community Interactions: Mutualism (+/+) & Commensalism (+/0)9m
- Community Structure35m
- Community Dynamics26m
- Geographic Impact on Communities21m
- 52. Ecosystems2h 36m
- 53. Conservation Biology24m
1. Introduction to Biology
Experimental Design
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