 Scientists follow a series of steps known as the scientific method in order to answer questions and solve problems.  They can use all steps, or just some steps.  Ultimate goal is to come up with reliable answers and solutions. Steps include: Make observations Ask question Form hypothesis Test hypothesis Analyze results Draw conclusions Communicate results

 An observation is any use of the five senses to gather information.  From the observation, scientists will form a hypothesis, which is simply an educated guess.  In order to test a hypothesis, scientists often run a controlled experiment.  This is a type of experiment testing only one factor, or variable, at a time. ▪ Two types of variables: ▪ Independent variable – the factor being manipulated or changed during the experiment performed. ▪ Dependent variable – the factor measuring the response, or result of the experiment performed.

 For example:  Mr. Cooper wishes to see whether or not students will perform better on tests with the presence of chocolate. ▪ The independent variable, what is being changed or manipulated during the experiment, is the presence of chocolate. ▪ The dependent variable, or the results, are the test scores.

 The International System (SI) of Units is the modern form of the metric system, based around the number ten. ▪ French derived “Le Systeme International d’Unites”

TThe more common prefixes can be remembered using a simple acronym: K ing H enry D ied B y D rinking C hocolate M ilk (kilo, hecto, deka, base unit, deci, centi, milli) +=

 Examples:  How many centigrams (cg) are in 1 hectogram (hg)? ▪ KHD B DCM ▪ 1 hectogram can also be written as 1.0 hectograms. You want to move the decimal point 4 places to the right since the letter “c” is 4 places to the right of letter “h”. Answer: 10,000 cg. are in 1 hg.  How many kilometers (km) are in 1 millimeter (mm)? ▪ KHD B DCM Answer: km. are in 1 mm.

 Scientific Notation is a system used to express very large or very small numbers. ▪ To convert a LARGE number to scientific notation, move the decimal point to the left until it is located to the right of the first nonzero number. The number of places you move the decimal point becomes the positive exponent of 10. ▪ Example: 18,930,000 = x 10 7 ▪ To convert a small number to scientific notation, move the decimal point to the right of the first nonzero number. Use the number of places you moved the decimal point as the negative exponent of 10. ▪ Example: = 2.7 x 10 -3

 A mathematical technique allowing you to convert units in order to solve problems is called dimensional analysis.  When you want to use a conversion factor to change a unit in a problem, you can set up the problem in the following way: ▪ Quantity sought (?) = quantity given x conversion factor ▪ Example: How many quarters are in 12 dollars?  ? quarters = 12 dollars x conversion factor  ? quarters = 12 dollars x 4 quarters 1 dollar

 Example: I am having a party this weekend and inviting 15 people, anticipating each person will eat 4 slices of pizza. Knowing each pizza has 12 slices, how many total pizzas will I need in order to have enough for everyone at the party?  ? pizzas = 15 persons x conversion factor  ? pizzas = 15 persons x 4 slices x 1 pizza 1 person 12 slices