# Science

• Determine which of the following observations (A-J) could lead to a testable hypothesis.

For those that are testable:

Write a hypothesis and null hypothesis

What would be your experimental approach?

What are the dependent and independent variables?

How will you collect your data?

How will you present your data (charts, graphs, types)?

How will you analyze your data?

• When a plant is placed on a window sill, it grows three inches faster per day than when it is placed on a coffee table in the middle of the living room.
• 2.     The teller at the bank with brown hair and brown eyes and is taller than the other tellers.

• When Sally eats healthy foods and exercises regularly, her blood pressure is 10 points lower than when she does not exercise and eats unhealthy foods.
• The Italian restaurant across the street closes at 9 pm but the one two blocks away closes at
• 10 pm.

• For the past two days the clouds have come out at 3 pm and it has started raining at 3:15 pm.
• George did not sleep at all the night following the start of daylight savings.
• Exercise 3: Conversion

For each of the following, convert each value into the designated units.

• 46,756,790 mg = _______ kg
• 5.6 hours = ________ seconds
• 13.5 cm = ________ inches
• 47 °C = _______ °F
• Exercise 4: Accuracy and Precision

• During gym class, four students decided to see if they could beat the norm of 45 sit-ups in a minute. The first student did 64 sit-ups, the second did 69, the third did 65, and the fourth did 67. 2. The average score for the 5th grade math test is 89.5.  The top 4th graders took the test and scored 89, 93, 91 and 87.
• Yesterday the temperature was 89 °F, tomorrow it’s supposed to be 88°F and the next day it’s supposed to be 90°F, even though the average for September is only 75°F degrees!
• Four friends decided to go out and play horseshoes. They took a picture of their results shown to the right:
• A local grocery store was holding a contest to see who could most closely guess the number of pennies that they had inside a large jar. The first six people guessed the numbers 735, 209, 390, 300, 1005 and 689.  The grocery clerk said the jar actually contains 568 pennies.
•  Exercise 5: Significant Digits and Scientific Notation

Part 1: Determine the number of significant digits in each number and write out the specific significant digits.

• 405000
•  0.0098
• 39.999999
• 13.00
• 80,000,089
• 55,430.00
• 0.000033
• 620.03080
• Part 2: Write the numbers below in scientific notation, incorporating what you know about significant digits.

• 70,000,000,000
• 0.000000048
• 67,890,000
• 70,500
• 450,900,800
• 0.009045
• 0.023 The length limit on Enotes responses prevents all 30 of your questions from being fully answered. In the future please cluster your questions according to format or subject matter, so that they will be easier to respond to, and so that problems may be more easily addressed; for example, in...

Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

The length limit on Enotes responses prevents all 30 of your questions from being fully answered. In the future please cluster your questions according to format or subject matter, so that they will be easier to respond to, and so that problems may be more easily addressed; for example, in Section 4: Accuracy and Precision, you did not include a picture that is necessary to answer question 3, and there are no instructions on what is to be done with the four questions.

3. Conversions

1. mg to kg

There are various ways of expressing the relationship between exponential factors; the simplest depiction here is to use grams. Grams are the “standard” upon which these measurements are based. A milligram is one-thousandth of a gram, and a kilogram is one thousand grams. Thus, 1000x1000 = 1 million milligrams would fit into a kilogram.

The easiest way to set up conversions is to write what you have, including units. Then, on the right side of this amount, write the conversion factor (the statement which relates the unit you have to the unit you want). 1 million mg = 1 kg is our conversion factor. Now orient the conversion factor so that the unit you already have is on the bottom; this way, the units will cancel out, leaving you with units of what you wanted to convert to.

46,756,790mg x (1kg/1,000,000mg) = 46.756790kg

2. hours to seconds.

The conversion factor is based on 60 seconds in a minute, and 60 seconds in an hour.

1 hour = 3600 seconds.

5.6 hours x (3600 seconds / 1 hour) = 20,160 seconds

3. cm to inches

The conversion here can be looked up from reference; 1cm = 0.3937 inches

13.5cm x (.3937 inches / 1cm) = 5.315 inches

4. C to F

This is more of a math equation than a conversion factor. To convert Celsius to Fahrenheit, multiply the Celsius temperature by (9/5) and add 32.

47 x (9/5) + 32 = 116.6 F

5. Significant Digits

General rules for sigfigs:

-Nonzero numbers always count.

-Zeros between nonzeros count

-Any zero at the end of a number (trailing) zeros count only if there is a decimal.

-Zeros at the beginning of a number never count

1. 3. Trailing nonzeros without a decimal do not count.

2. 2. Leading zeros do not count.

3. 8. All nonzeros count.

4. 4. Trailing zeros with a decimal count.

5. 8. Zeros between nonzeros count.

6. 7.

7. 2.

8. 8.

Scientific Notation

The rules for scientific notation are;

-The expression must be in the form of (number) times (ten to a power)

-The initial number must be a single-digit integer

-The integer must be followed by a decimal if there is more than one significant figure in the original number

-Any additional significant digits appear after the decimal

To find the appropriate power of ten:

If the number is greater than zero, count from the decimal place (or the “ones”-value digit) up to the first number.

If the number is less than zero, count the places between the decimal place and the first number, plus the initial zero.

1. 7 x 10e10
2. 4.8 x 10e-8
3. 6.789 x 10e7
4. 7.05 x 10e4
5. 4.509008 x 10e8
6. 9.045 x 10e-3
7. 2.3 x 10e-2
Approved by eNotes Editorial Team