HW #7 for 10/1

1) HW #7: pg. 67 #3-7, pg. 87 #19-20, 22-24, 27-28
2) Take home lab due Fri. Oct. 9th

HW #6 for 9/29

1) HW #6 for 9/29: pg. 86 #7-11, 14, 16
2) Take Home Lab #1 due Thur. Oct. 9th

Take Home Lab #1

Take Home Lab #1

Question:  Which variables affect the period of a pendulum?

Safety:  Do not swing the pendulum in a dangerous manner. Washers can be a choking hazard, so keep them out of the reach of children.

Materials: Thread or dental floss, washers, a timer

Procedure: In this lab, you will determine which of three factors determines the period of a pendulum. A pendulum is a weight hanging from a string. You will use a piece of thread or dental floss (approximately 50 cm) and washers to make your pendulum. The period is how long it takes the pendulum to swing back and forth once. The three factors, or variables, that you will test are the mass at the end of the pendulum, the angle from which the pendulum is swung, and the length of the pendulum. You need to follow the rules of a good experiment (i.e., changing only one variable at a time, repeating each trial more than once, etc.). This procedure will be determined by you but here are some ideas and tips:

1. Count your pendulum for 10 swings (back and forth is one swing) for each of your trials. Then use a timer to record how long it takes for those 10 swings.

2. You will need to make 27 total trials for this experiment.

3. You would first have to experiment with the angle of the swing—you would do three swings at a low angle, three swings at a medium angle and three at a high angle.  During those trials, you do not change the mass at the end or the length of the string, those must stay the same.

4. Then you could change the amount of mass at the end of the

string. Keep the length of the string the same and also the angle that you swing it at the same. You would need to do nine trials of

this, three trials with a heavy mass, three with a medium mass, and three with a lightweight mass.

5. Look for significant changes in your data, a time change of 1.2 sec to 1.5 sec is not a big change. But a change of 1.2 sec to 3.5 sec is significant.

1. Data charts: Because you will determine the procedure, you will also determine the data charts. You will need to make three data charts, one for the length of the string, one for the change in mass, one for the change in angle. Each data chart will have nine data points for that experiment.

For example:

Length of string	Trial #1	Trial #2	Trial #3	Average
Short string
Medium string
Long string

Post-Lab Questions:

2. Which variable or variables had the biggest effect on the period of the pendulum?

3. Can you relate this information to your experiences on or around playground springs? Explain.

4. Draw three bar graphs one for string length, one for angle and one for mass. Each graph should have the variable being tested on the x-axis and the period (time in seconds) on the y-axis. Start the y-axis at 0 sec to avoid amplifying small changes. Graph the average swing time for each of the conditions.

HW #5 for 9/28

1) Read Chapter 3
2) HW #5 pg. 55 #2-6, pg. 58 exercise 3.1 (in yellow box), pg. 59 #5-6
3) Turn in test corrections on Monday, show work on a separate sheet of paper and staple to original test.

Mixture Separation Challenge

Make sure to answer all FIVE questions, look on pg. 40-41 in your textbook for guidance.

•1) Write the steps that you used to separate your mixture. Make sure to name what laboratory equipment you used to help you.

•2) Is this a homogeneous or heterogeneous mixture? Explain why.

•3) Now that you attempted the separation, what would you change for next time? What worked well?

•4) Explain the procedures (make sure to name them) and describe what they did to separate the substances.

•5) Explain how density was used to separate the mixture.

HW #4 for 9/22

1) HW #4: pg. 47 1, 4-5, 7-12
2) Test corrections due Tuesday 9/22, put corrections on a separate sheet of paper and show your work, then staple to original test
3) Turn in late composition books tomorrow

HW #3 for 9/21

1) HW #3 pg. 40 exercise 2.3 (yellow box), pg. 46 #15-20
2) Turn in late composition books
3) Test corrections due on Tuesday (do your corrections on a separate sheet of paper and show your work then staple to your original test).  I will be after school on Friday & Monday to help you make corrections.

HW #2 for 9/17

1) HW #2: pg. 43 #1-7
2) Any late composition books turn in Friday

HW #1 for 9/15

HW #1:
1) pg. 30 #1,3; pg. 45 #1-5
2) Read Chapter 2

Study Guide for test 9/11

Study Guide for Chapter 5 Test (I can't make exponents on this program!)

1) Be able to turn a number from a "regular" number to scientific notation
--such as 1,020,000 = 1.02 x 10(exponent of 6)
--such as 0.0000506 = 5.06 x 10 (exponent of -5)
2) Turn a scientific notation into a "regular" number
--such as 7.94 x 10(exponent -7) = 0.000000794
--such as 2.78 x 10 (exponent 5) = 27800
3) Know how to convert between metric units
--such as 2.5 kg to g (KHDUDCM) move three spaces to the right, move decimal same = 2500 g
4) Know the formula for Density = mass/volume and how to use it
--know that grams or kilograms is mass
--know that cubic centimeters or milliliters is volume
--remember that density always requires two units such as g/mL or g/cm3 
--know how to find the volume of a regular object such as a cube
--know how to find the volume of an irregular object such as a pencil

Will it sink or float lab

Will It Sink or Float?

1. Make observations and predictions for each of the objects.

2. Measure the mass of one of the objects on the scale. Record in the data table.

3. Place enough water in the graduated cylinder to cover your object completely. Record

the volume of the water on the data table below under V₁. 

4. Then add the object to the water and record the volume on your data table under V₂.

5. Then subtract V₂ – V₁ to find the volume of the object. Then add the volume to your data table below.

6. Then calculate the density of your object with the formula D = M/V. Density = mass/volume

Object	Observations (think about why objects sink or float)	Prediction (sink or float)	Mass (g)	Volume (mL)	Density (g/mL)	Result: sink or float?
Condiment package
Carrot
Rock
Die
Cork

Object	Volume of water without object (mL)  V1	Volume of water with objects (mL) V2	Volume of object (mL) V2 – V1 = volume of object
condiment package
carrot
rock
die
cork

3. Which objects sank in water? What do the items that sank in the water have in common? What is the relationship in their density?

4. Which objects floated in water? What do the items that floated in the water have in common? What is the relationship in their density?

5. Explain the procedure how to find the density of an irregular object like a marble to someone who has never done this lab before.

6. Draw a model of what the molecules look like (inside that you are unable to see) for each of the five different objects.  Think about the density of each object and why they have a different density.  What is the cause of this difference then show that in your pictures.

HW for 9/10

1) HW #7 pg. 167 #51-53, 55-58
2) Back to school night Thursday from 5-7pm, extra credit if your parents attend
3) Composition books & all late HW due Friday
4) Test Friday, study guide posted on website

HW #6 for 9/8

Homework for Tuesday 9/8:
1) HW #6: pg. 128 exercise 5.2, pg. 132 #1-2, pg. 164 #1-3, 5-6, pg. 166 #39 g & h, #40 a & b
2) Homework drop in afterschool

HW #5 (UPDATED) for 9/3

1) Updated HW--HW #5—pg. 132 #3-4, pg. 164 #9-10 (turn in tomorrow)