2 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.
3 What are the steps in the scientific method? Define the problemGather informationMake an hypothesisTest your hypothesisReview your resultsMake a conclusion
4 What are variables?In an experiment these changing quantities are called variables, and an experiment usually has three kinds:independentdependentcontrol
5 The 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."
6 The Independent Variable The independent variable is the one that is changed by the scientist.In an experiment there is only one independent variable.
7 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.
8 Examples:“For example, if you open a faucet (the _________ variable), the quantity of water flowing (__________ variable) changes in response-the water flow increases.”
9 How to identify the dependent variable? To be predictedThe response variableThe outcomeA variable that is not under the experimenter's control.
10 Difference between Variables IndependentOnly oneInputManipulated varIs under the control of the ExperimenterCauseDependentOne or moreOutputResponse varResults and dataNot controledEffects
11 How to identify the independent variable? The causeThe inputThe manipulated variableThe variable that is changed on purpose in an experiment.
12 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.
17 How to remember? K H D d c m Basic unit King Henry Died Drinking ChocolateMilkHBasic unitDdmass, length, volumecm
18 Basic Unit Kilo Left Hecto Decka Grams, Liters, meter deci centi Right milli
19 Practice 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
20 Practice 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
21 Practice 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
22 Practice 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
23 Practice 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
24 Answer tofollowing Problems 35L = KL46 g = Hgmg = Dg9.53 mm = m7.908 cL = L0.521 Hm = cm
25 35L = 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
26 46 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
27 mg = 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
28 9.53 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
29 7.908 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
30 0.521 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