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What happened here? Read the following What happened here? Read the following story and see if you can figure it outstory and see if you can figure it out

Imagine you are a pilot from USA getting ready for your return flight from Canada to New York City. Groundcrew asks for your fuel status, you read them “12,000”. They know you need 8,000 kg of fuel for the flight, and so all seems good. When you get a little more than ½ way to your destination, an alarm goes off saying one engine shut down, then a few minutes later, the other engine is down…. and a loud sound and flashing lights tell you that you are about to run out of fuel!!! All goes silent and the voice recorder registers your voice yelling: “Oh S%$#!” You have to make a crash landing, and almost hit a whole crowd of people on an airstrip that had recently been converted to a drag racing strip

(this is based on a true story)

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Analysis Questions

Why is it important to have a large sample size in any experiment?

Data will be more accurate, don’t rely on just one or two results

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Analysis Questions

Why is it important to repeat the experiment many times?

To see if the same results are obtained each time.

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Analysis Questions

What is the importance of the control?

To have a normal sample to compare your experimental sample against.

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Analysis Questions

How is a theory different than a hypothesis?

Hypothesis is just a guess, where a theory has been proven over and over and accepted as the answer.

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Analysis Questions

Why is it so important that a scientist accurately describes the procedure

used in the experiment?

So scientists can repeat the experiment and verify the results.

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Analysis Questions

What is the difference between the independent and the dependent

variables in an experiment?

We collect/measure the dependent variable data

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Analysis Questions

In a “controlled experiment”, why must all of the variables, except one, be kept constant throughout the experiment?

So we know which variable made the difference or not.

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Unit 1Measurement Notes

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Standard International UnitsWe need to use standard units across the world so we can compare data. We use the metric system –based on 10’s (easier)

•Distance: Meters How far? •Volume: Liters How full/ how much space?

•Mass: Grams How much matter (related to weight)

•Time stays the same 1 hr is 60 minutes etc.

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Metric Conversion Practice• You will need to know how to convert from

Kilometers to meters, centimeters to meters, grams to kilograms etc.

Concepts of Physical Science

Graphing – A tool you need

Write down underlines items

What do graphs do?

Graphs show the relationship between two or more things.

Graphs help you visualize data and see what’s going on.

Types of Graphs:

Line Graph

shows the relationship between two variablesD

epen

den

t V

aria

ble

Independent Variable

Dependent & Independent

Dependent Variable: The results, what you measure. On the y axis.

Independent Variable:–on the x axis, usually time etc.

For example…

You measure the height of a tree every day for the years that you are in high school. By the time you graduate, you have 4, 5, or even 6 years of data.

What’s the independent variable? What’s the dependent variable?

Height of the tree (cm)

Time (days

Types of Graphs

Bar Graph

shows information collected by counting

Types of Graphs

Pie Graph

shows distribution of parts within a whole

Next Steps for Measurement Lab

When you are done with your group members, get the measurements of 4 more people in your class.

You need a total of 8 data points to graph.

Turn over paper and follow directions on how to graph

Y-axis

X-axis

What can you calculate from this line?

Slope!

Slope = y2 – y1/x2 – x1

or y2 – y1

x2 – x1

The slope shows the rate of change between x and y.

And then… the slope-intercept formula for a line: y = mx + b

y = y valuem = slopex = x valueb = y-intercept (where the line crosses the y axis)

For example:

Back to the height stuff… If b = 55 cm, m=.32 and time (your x-

value) = 99 days, what’s your height (your y value)?

Height of the tree (cm)

Time (days

MATH!

It’s simple…

b = 55 cm, m=.32, x=99. What’s y?

y = mx + b, right?

y = .32(99) + 55

y = 86.68 cm

Height of the tree (cm)

Time (days