The Scientific Method Mr. Luis A. Velazquez.

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The Scientific Method Mr. Luis A. Velazquez

What is the scientific method?
Is a step by step process to understand nature. Scientists use an experiment to search for cause and effect relationships in nature. In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way.

What are the steps in the scientific method?
Define the problem Gather information Make an hypothesis Test your hypothesis Review your results Make a conclusion

What are variables? In an experiment these changing quantities are called variables, and an experiment usually has three kinds: independent dependent control

The control variable Controlled variables are quantities that a scientist wants to remain constant, and he must observe them as carefully as the dependent variables. Why? Most experiments have more than one controlled variable. Some people refer to controlled variables as "constant variables."

The Independent Variable
The independent variable is the one that is changed by the scientist. In an experiment there is only one independent variable.

The dependent variable
The dependent variable changes in response to the change the scientist makes to the independent variable. The number of dependent variables in an experiment varies, but there is often more than one.

Examples: “For example, if you open a faucet (the _________ variable), the quantity of water flowing (__________ variable) changes in response-the water flow increases.”

How to identify the dependent variable?
To be predicted The response variable The outcome A variable that is not under the experimenter's control.

Difference between Variables
Independent Only one Input Manipulated var Is under the control of the Experimenter Cause Dependent One or more Output Response var Results and data Not controled Effects

How to identify the independent variable?
The cause The input The manipulated variable The variable that is changed on purpose in an experiment.

if we want to measure how much water flow increases when we open a faucet, it is important to make sure that the water pressure (the controlled variable) is held constant. That's because both the water pressure and the opening of a faucet have an impact on how much water flows. If we change both of them at the same time, we can't be sure how much of the change in water flow is because of the faucet opening and how much because of the water pressure. Most experiments have more than one controlled variable.

The SI Unit System Mr. Luis A. Velazquez

PREFIX SYMBOL FACTOR yotta Y 1024 zetta Z 1021 exa E 1018 peta P 1015 tera T 1012 giga G 109 mega M 106

PREFIX SYMBOL FACTOR kilo K 103 hecto H 102 deka D 101 deci d 10-1 centi c 10-2 milli m 10-3 micro 10-6 nano n 10-9 pico p 10-12 femto f 10-15 atto a 10-18 zepto z 10-21 yocto y 10-24

Prefix Kilo 10x 10 x 10 = 1000 = 103 Hecto 10 x 10 = 100 = 102
Decka x1 = = 101 deci /10 = = 10-1 centi /100 = = 10-2 milli /1000 = = 10-3 1x1 = =

How to remember? K H D d c m Basic unit King Henry Died Drinking
Chocolate Milk H Basic unit D d mass, length, volume c m

Basic Unit Kilo Left Hecto Decka Grams, Liters, meter deci centi Right
milli

Practice Problems 5 Kg =_______ g 5000 3 Answer 5000
Kilograms are bigger than Grams So you need to multiply this means you move the decimal to the right How many times? 5 Kg =_______ g 5000 3 Answer 5000

Practice Problems .045 cg =_______ g .00045 2 Answer .00045
centigrams are smaller than grams So you need to divide this means you move the decimal to the left How many times? .045 cg =_______ g .00045 2 Answer .00045

Practice Problems 36 Dg =_______ g 360 1 Answer 360
Dekagrams are bigger than grams So you need to multiply this means you move the decimal to the right How many times? 36 Dg =_______ g 360 1 Answer 360

Practice Problems 7 mg =____________ Kg 0.000007 6 Answer 0.000007
milligrams are smaller than Kilograms So you need to divide this means you move the decimal to the left How many times? 7 mg =____________ Kg 6 Answer

Practice Problems 9 L =_______ mL 9000 3 Answer 9000
Liters are bigger than milliliters So you need to multiply this means you move the decimal to the right. How many times? 9 L =_______ mL 9000 3 Answer 9000

35L = KL 46 g = Hg mg = Dg 9.53 mm = m 7.908 cL = L 0.521 Hm = cm

35L = KL Liter are smaller than Kiloliters so you divide or move your decimal to the left. You move your decimal to the left three times The answer is .035 KL

46 g = Hg Grams are smaller than Hectograms so you divide or move your decimal to the left. You move your decimal to the left two times . The answer is 0.46Hg or .46 Hg

mg = Dg milligrams are smaller than Decagrams so you divide or move you decimal to the left. You move your decimal to the left four times. The answer is Dg

9.53 mm = m millimeters are smaller than meter so you divide or move you decimal to the left. You move your decimal to the left three times The answer is meters

7.908 cL = L centiliters are smaller than Liters so you divide or move you decimal to the left. You move your decimal to the left two times. The answer is Liters

0.521 Hm = cm Hectometer are bigger than centimeters so you multiply or move you decimal to the right. You move your decimal to the right four times. The answer is cm