2What 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.
3What are the steps in the scientific method? Define the problemGather informationMake an hypothesisTest your hypothesisReview your resultsMake a conclusion
4What are variables?In an experiment these changing quantities are called variables, and an experiment usually has three kinds:independentdependentcontrol
5The control variableControlled 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."
6The Independent Variable The independent variable is the one that is changed by the scientist.In an experiment there is only one independent variable.
7The 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.
8Examples:“For example, if you open a faucet (the _________ variable), the quantity of water flowing (__________ variable) changes in response-the water flow increases.”
9How to identify the dependent variable? To be predictedThe response variableThe outcomeA variable that is not under the experimenter's control.
10Difference between Variables IndependentOnly oneInputManipulated varIs under the control of the ExperimenterCauseDependentOne or moreOutputResponse varResults and dataNot controledEffects
11How to identify the independent variable? The causeThe inputThe manipulated variableThe variable that is changed on purpose in an experiment.
12if 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.
17How to remember? K H D d c m Basic unit King Henry Died Drinking ChocolateMilkHBasic unitDdmass, length, volumecm
18Basic Unit Kilo Left Hecto Decka Grams, Liters, meter deci centi Right milli
19Practice Problems 5 Kg =_______ g 5000 3 Answer 5000 Kilograms are bigger than GramsSo you need to multiply this means you move the decimal to the rightHow many times?5 Kg =_______ g50003Answer5000
20Practice Problems .045 cg =_______ g .00045 2 Answer .00045 centigrams are smaller than gramsSo you need to divide this means you move the decimal to the leftHow many times?.045 cg =_______ g.000452Answer.00045
21Practice Problems 36 Dg =_______ g 360 1 Answer 360 Dekagrams are bigger than gramsSo you need to multiply this means you move the decimal to the rightHow many times?36 Dg =_______ g3601Answer360
22Practice Problems 7 mg =____________ Kg 0.000007 6 Answer 0.000007 milligrams are smaller than KilogramsSo you need to divide this means you move the decimal to the leftHow many times?7 mg =____________ Kg6Answer
23Practice Problems 9 L =_______ mL 9000 3 Answer 9000 Liters are bigger than millilitersSo you need to multiply this means you move the decimal to the right.How many times?9 L =_______ mL90003Answer9000
24Answer tofollowing Problems 35L = KL46 g = Hgmg = Dg9.53 mm = m7.908 cL = L0.521 Hm = cm
2535L = KLLiter are smaller than Kiloliters so you divide or move your decimal to the left.You move your decimal to the left three timesThe answer is .035 KL
2646 g = HgGrams 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
27mg = Dgmilligrams 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
289.53 mm = mmillimeters are smaller than meter so you divide or move you decimal to the left.You move your decimal to the left three timesThe answer is meters
297.908 cL = Lcentiliters 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
300.521 Hm = cmHectometer 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