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Which of the measureable factors in your pendulum is most precise? Least precise? How can you tell?. Take 15 minutes to finish collecting data for your 2 nd page pendulum lab. Significance. Why do we use significant figures? Period: 1.235, 1.175, 1.443, 1.336 Avg = 1.29725. Significance. - PowerPoint PPT Presentation
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Which of the measureable factors in your pendulum is
most precise? Least precise? How can you tell?
Take 15 minutes to finish collecting data for your 2nd page
pendulum lab
Significance
• Why do we use significant figures?
• Period: 1.235, 1.175, 1.443, 1.336
• Avg = 1.29725
Significance
• Why do we use significant figures?
• Period: 1.235, 1.175, 1.443, 1.336
• Avg = 1.29725
• Really?!?!?
• How about 1.3
Significance
• Why do we use significant figures?
• Period: 1.300, 1.301, 1.301, 1.301
• Avg = 1.30075
• 1.301
Rules for significant figures
• All non-zero numbers are significant
• 2.3563
• 24456
• 84323445
Rules for significant figures
• All trapped zeros are significant (in between other significant numbers)
• 2.30563
• 204456
• 843234405
Rules for significant figures
• All leading zeros are not significant
• 0.00000230563
• 204456
• 0.0000843234405
Rules for significant figures
• zeros at the end are significant only if there is a decimal point
• 2.3563000 - yes
• 24456000 - no
• 843234450000.0 - yes
Please take out your homework.
• Warm-up:
• Make a guess (based on your data) how long it will take for my 3 m long pendulum to complete one period.
• Write down 20 different units of measure
Rules for significant figures• Adding and subtracting, use the least significant
digit:
• 2.3546
• +1.5
• 3.8546 ->3.9
• 0.135
• +2.55489
• 2.68989 -> 2.690
Rules for significant figures• Multiplying and dividing, use the least number of
significant digits:
• 2.3546 (5 significant digits)
• +1.5 (2 significant digits)• 3.5319 ->3.5 (answer has 2)
• 0.135 (3 significant digits)
• +2.55489 (6 significant digits)
• 0.34491015 -> 0.345 (3 significant digits)
Add the following distances using correct significant figures
3.45 m + 9.82 m + 13.653 m + 0.23 m
Multiply the following distances using correct significant figures
(3.45 m)(9.82 m )(13.653 m )(0.23 m)
Scientific Notation
Scientific Notation
Most numbers are really annoying
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
38000
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
38000000
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380000000
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380000000 m
How big is an atom?
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380000000 m
How big is an atom?
0.000
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380000000 m
How big is an atom?
0.00000
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380000000 m
How big is an atom?
0.0000000
Scientific Notation
Most numbers are really annoying
How many meters is it to the moon?
380000000 m
How big is an atom?
0.0000000001 m
Scientific Notation
Let’s write those in a not annoying way.
380000000 m
Scientific Notation
Let’s write those in a not annoying way.
380000000 m x 101
Scientific Notation
Let’s write those in a not annoying way.
380000000 m x 102
Scientific Notation
Let’s write those in a not annoying way.
380000000 m x 108
Scientific Notation
Let’s write those in a not annoying way.
380000000 m x 108
Check our sig figs, though…
Scientific Notation
Let’s write those in a not annoying way.
38 m x 108
Check our sig figs, though…
Scientific Notation
Let’s write those in a not annoying way.
00000000001 x 100
Scientific Notation
Let’s write those in a not annoying way.
00000000001 x 10-10
Scientific Notation
Let’s write those in a not annoying way.
00000000001 x 10-10
Check our sig figs again
Scientific Notation
Let’s write those in a not annoying way.
1 x 10-10
Check our sig figs again
Units
• Length – meter – m
Units
• Length – meter – m
• Time – second – s
Units
• Length – meter – m
• Time – second – s
• Temperature – Kelvin – K
Units
• Length – meter – m
• Time – second – s
• Temperature – Kelvin – K
• Mass – kilogram – kg
Units
• Length – meter – m
• Time – second – s
• Temperature – Kelvin – K
• Mass – kilogram – kg
• Electric current – Ampere – A
• Amount – mole – m
• Luminous intensity – Lumen - L