Do now What is wrong with the set-up to this question; How many seconds are in a year? Seconds / year = 1 year x (1 yr/365 days) x (1 day/24hrs) x (1 hr/60 minutes) x (1min/60s)

Conversion Graded Assignment

Graphing Why are graphs important? – They help make sense of data and can be used to make predictions

Variables There are always 2 variables; the dependent and the independent Guess which one depends on the other… – The DEPENDENT. It changes because of the independent – The independent is the thing that we change/control

Practice: ID the dependent variable Measuring volume of gas trapped in a cylinder as pressure is applied Volume depends on the pressure so it is the dependent variable Pressure is what we are changing/controlling so it is the independent variable

Practice: Identify the independent variable Experiment: Measuring reaction rate as temperature is increased by applying heat Temperature is what we control and is the independent variable Reaction rate depends on temperature and is thus, the dependent variable

Page 26 of your homework packet A student did an experiment to find out how light energy affects the temperature of soil. A light was placed over a dish of soil which contained a thermometer. The temperature of the soil was measured at the start of the experiment before the light was turned on, and then measured again each minute for five minutes once the light was turned on. The measurements were recorded on the data chart below:

Page 26 of your homework packet What is the independent variable? What is the dependent variable?

Graphs need to contain the following: 1) X and Y axis labeled with units. Dependent variable goes on the Y axis 2) A numerical scale representing uniform increases in each variable (1 box = 4 seconds ALWAYS, not 4 here, 16 here, 1 there) 3) Title (Dependent var. vs. Independent var.) 4) Data points circled with point protectors 5) A line either connecting data points or a best fit curve/line P 15

Is this acceptable?

Is this acceptable

Looking at the homework, 1b Which variable is going to go on the x axis (horizontal) and which is going to go on the y axis (vertical) X-axis = independent variable… – Time Y-axis = dependent variable… – Temperature

Using Graphs To Predict Interpolation vs. Extrapolation

Best fit lines They don’t try to connect all the dots – Try to make a line with the same # of points above and below it – Its kind of an average of all the points

Relationships Either Direct or Indirect Direct: as the independent variable increases, the dependent variable increases Indirect: as the independent variable increases, the dependent variable decreases

DirectIndirect

One last thing…Size The bigger the graph, the better. Should take up more the ¼ of the page This will determine the type of scale you will need to use when setting it up

Good

Bad

Now… Take this time to work on the homework (p 26-27) Done? Work on the review sheet for the whole unit!