Review

• Science is a system of knowledge based on facts or principles.
• The scientific investigation is a systematic formula for acquiring new knowledge and furthering previous knowledge. The basic steps are: observation, hypothesis, experimentation, and conclusion.
• Data is the information collected during an experiment. Precise and accurate data should be used and reported. Accuracy is a description of how close a measurement is to the true value of the quantity measured. Precision is the exactness of a measurement.
• Many scientists use graphs and charts to showcase data. The most commonly used charts or graphs are line graphs, bar graphs, and pie charts.
• Scientific notation takes the form of M×10ⁿ where 1 ≤ M < 10 and n represents the number of decimal places to be moved. Positive n indicates the standard form is a large number. Negative n indicates a number between zero and one.
• A significant figure is a prescribed decimal place that determines the amount of rounding off to be done based on the precision of a measurement.
• Mean is the arithmetic average of a list of numbers. It is found by adding all the numbers in the list and dividing by the number of elements in the list.
• Median is generally the middle element in a list of numbers, found by ordering them from least to greatest.
• Mode is the number that occurs most often in a list of numbers.
• It is important to know basic lab safety and to convey this to our students.
• Different tools are used for many different experiments in a science laboratory. Meters are used to take precise readings of experiments conducted.
• Matter is made up of elements which are made up of atoms.
• Atoms with a charge, either positive or negative are called ions. Atoms combine to form molecules.
• Elements are the simplest substances on earth. Just like atoms, elements combine to form compounds and mixtures.
• The two main types of compounds are ionic and molecular compounds.
  • Ionic compounds are compounds composed of cations and anions combined to have a neutral net charge.
  • Molecular compounds are substances consisting of atoms that are covalently bonded.
• Mixtures are a combination of more than one pure substance. A pure substance is any matter that has a fixed composition and definite properties.
  • Heterogeneous mixtures are mixtures that are not uniformly distributed.
  • Homogeneous mixtures are uniformly distributed.
• There are three main states of matter: solid, liquid, and gas.
  • Solids have a rigid volume and vibrate about a fixed position.
  • Liquids flow more freely than solids and their volume will assume the shape of the container they are placed into.
  • Gases are very free flowing and have the most energy of the three states.
• Newton’s First Law states that an object at rest remains at rest and an object in motion maintains its velocity unless either object experiences an unbalanced force.
• Newton’s Second Law states the unbalanced force acting on an object equals the object’s mass times its acceleration. (F = ma)
• The electromagnetic spectrum is the full range of light at different frequencies and wavelengths. The electromagnetic spectrum consists of radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays, and gamma rays.
• DNA contains the genetic instructions specifying the biological development of all cellular forms of life and consists of the repeating nucleotides thymine, adenine, guanine and cytosine.
• RNA serves as the template for translation of genes into proteins.

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