1. Welcome to Physics!

2. Class Policies and Procedures

3. Lab Safety Contract

4. Marshmallow Challenge!
As a team build the tallest free-standing structure
20 sticks spaghetti
One meter of tape
One meter of string
One marshmallow
Marshmallow on top
18 minutes!

5. Do you really know how to take accurate and precise measurements?
Grab a ruler and measure the length of your writing utensil.
Record your answer in your notes.
Be nice and share the rulers 

6. How to take a measurement
What is the smallest increment?
What length do we know?
What length do we estimate?
0.1 cm
5.3 cm
5.35 cm

7. Rules with Instruments
Estimate one place past smallest calibration
Can only measure with same precision as device
Which ruler is more precise? This one or the one you used?

8. Are you good at texting?
Is there a correlation between the length and circumference of your thumb and your “fluency” in texting?
Measure and record the length and circumference of your dominant thumb

10. What is the standard of measurement for science?
The Metric System – SI Units
Related by powers of 10
ALL SCIENTISTS, WORLD WIDE, USE SAME MEASURMENT!

11. Standard SI base units
Length?
Mass?
Time?
Volume?

12. Derived Units Combination of base units
Can you think of any examples??
Area
Density
Speed
Weight

13. Gosh, do we have to show units?
No Naked numbers……the number is meaningless if you do not know how it was measured. Example: My walking speed is 1m/s

14. Day 2

15. Which numbers are significant?
All non-zeroes
Zeros in between non-zeroes
Zeros to the right of non-zeroes if decimal included
(0 is significant)
(0 is not significant)

16. Which are not significant?
Zeros to the left of non-zeroes
(0s are not significant)
Zeros to the right of non-zeros, if there is no decimal
(0s are not significant)

17. Practice How many significant digits are in the following: 2.34 2,340
234.0
100,234
100,230.0

18. Multiplication/Division Rule
Answer should contain only as many SFs as the measurement with the fewest SFs

19. Multiply
9.315m x 1.355m =

20. Multiply
9.315m x 1.355m = m2 Express answer as m2

21. Conversions Review…..How many sig figs? 100 101 0.001 0.00100
How do I convert between meters and kilometers? Or meters and centimeters?
Review…..How many sig figs?
100
101
0.001

22. Prefixes for base units
Giga (G) 1,000,000,000
Mega (M) 1,000,000
Kilo(k) 1,000
Hecta (h)
Deca(d) 10
Base
Deci(d)
Centi(c)
Milli(m)

23. KHDUDCM
Kids
Have
Died
Using
Dumb
Crummy
Metrics

24. In Class Examples Distance from sun to Mars is 227 800 000 000 m
What is this in kilometers?

25. Opening Activity 1. Convert the following to the designated units.
260,000,000m to km
s to ms
2. How many sig figs are in the following numbers?
260,000,000m s

26. Opening Activity 1. Convert the following to scientific notation:
260,000,000m 2.6 x 108m
s x 10-7s
2. Convert the following to the designated units.
260,000,000mm to km 260km
s to ms ms
3. How many sig figs are in the following numbers?
260,000,000m 2
s 4

27. Precision vs. accuracy
Precision refers to the smallest available unit of measurement on a device
1 meter is not the same thing as meters
Accuracy describes how repeatable a measurement might be
A measurement could be precise ( meters), but not very accurate ( m, m, m, m)
Or, it could be accurate (1m, 1m, 1m, 1m), but not very precise
Significant Figures help reflect the precision of a measurement

28. Scientific Notation
We use scientific notation to simplify the format of very large and very small numbers
When done properly, using scientific notation will not change the value of a number
We use exponents and powers of 10 w/ scientific notation
Format is always…
#.# x 10#

29. Scientific Notation
When simply changing one number from standard to scientific notation, be sure to retain all significant figures
Example – 1,200,000 = 1.2 x 106
Example – 1,205,001 = x 106
Other times you may be asked to reduce the number of significant figures
Example – Express 1,205,001 with three sig. figs. = 1.21 x 106
Example – Express 1,296, 789, 005,231 with four sig. figs. = x 1012

30. Practice – convert to scientific notation
1,200,000 m =
1,200 m =
89 s =

31. Practice – convert to scientific notation
1,200,000 m = 1.2 x 106 m
1,200 m = 1.2 x 103 m
89 s = 8.9 x 10 s

32. Practice – convert to scientific notation with three sig. figs.
1,200,000 m =
1,200 m =
s =

33. Practice – convert to scientific notation with three sig. figs.
1,200,000 m = 1.20 x 106 m
1,200 m = 1.20 x 103 m
s = 8.99 x 106 s