What's Happening!

What is the pH number of each liquid?

2009-04-26T21:02:00.005-04:00

Objective: To determine the pH number of the different liquids and to classify the liquids as acids or bases.

Materials: (per group)
·Sheet of white paper
·Test tray
·10 liquids with droppers
·pH paper
·pH chart

Procedure:
1.Make your pH predictions for the 10 liquids listed in the table below.
2.Collect materials for your group.
3.Place the white sheet of paper under your test tray.
4.Place a small piece of pH paper in 10 individual cups of the test tray.
5.Place 1 drop of liquid #1 in the first cup of the test tray. Record the pH of the liquid, using the pH chart, in your data table.
6.Repeat step 5 for each of the remaining liquids.
7.Once you have tested each liquid, complete the data table by identifying the liquid and answering whether or not your pH prediction was correct.

You will be testing the following liquids:
vinegar, pop, water, hydrochloric acid, ammonia, bleach, dish washing detergent, milk, lemon juice, antacid

Make a chart listing the liquids you are testing and write your pH prediction for each of the liquids

DATA TABLE
The substances you are testing are only labeled as numbers. You will not know the identity of each liquid until you have found their pH. Once you have determined the pH of each substance, use your textbook to help you identify the liquids. Label each as an acid, base or neutral by placing the liquid names in the appropriate place of the pH scale.

Unknown liquid pH of liquid Identity of liquid Was your prediction correct?
#1
#2
#3
#4
#5
#6
#7
#8
#9
#10

Conclusion:
1.How many of your predictions were correct?

2.How did you make your predictions? How did you know if they were an acid or base to begin with?

Observing Plant Cells

2009-04-26T20:51:00.006-04:00

Elodea Leaf

1. Add a drop of water to a glass slide.
2. Remove a leaf from an elodea plant and place it in the drop of water. Place a coverslip on the leaf.
3. Observe the leaf under low power, then medium, then high power.
4. Make a drawing of an Elodea cell on a separate sheet of paper.
5. Label the following parts in your drawing: cell wall, cell membrane, nucleus, chloroplasts.

Discovering Mitosis

2009-04-26T20:30:00.004-04:00

Materials
Paper Plates
Colored Pipe Cleaners
Masking Tape

Procedure
1.Get 2 paper plates and a set of 3 pairs of pipe cleaners.

2.Place the 2 paper plates on top of each other. Scramble the 6 pipe cleaners so that the colors are all mixed. Place them on the paper plates. Draw this on a separate sheet of paper and label it Figure A.

3.Separate the strands according to color. Twist 2 of the same color pipe cleaners
around each other one time in the middle. Place each pair on the paper plates.
Draw this and label it Figure B.

4.Line up the pairs of pipe cleaners along the middle of the paper plate. Draw this and label it Figure C.

5.Separate the 2 paper plates and move them partially apart. Also, separate each pipe cleaner and move 1 of each color to opposite ends of the 2 plates. Draw this
and label it Figure D.

6.Scramble the pipe cleaners on each of the plates. Separate the paper plates even
further. Draw this and label it Figure E.

7.Completely separate the paper plates. Draw this and label it Figure F.

Critical Thinking & Application

1.Label each stage of the cell cycle for Figures A-F.

2.Each of the letters A through F represent a stage in the life of a cell. What do you see happening to the cell from the 1st stage through the 6th stage?

3.The colored pipe cleaners represent genetic material in the cell. How does this
genetic material appear in the cell in stage A?

4.What happens to the strands of genetic material in stages B and C?

5.What has happened to the strands of material by the time they reach stage D?

6.Describe the genetic material inside each of the circles in stage F. What do these
circles represent? How does the genetic material in the 2 circles compare?

Measuring With Metrics

2009-03-03T17:15:00.004-05:00

Purpose: To measure various items and distances with a meter stick and compare them with the measurements attained with “old-time measurements”

Background: A cubit measures from elbow to tip of middle finger, a digit measures the width of the index finger, a span is the width of the hand from the thumb to little finger, feet measures the length of the foot (in your shoe), and a pace is a Roman soldier giant step)

Materials: paper, pencil, meter stick (You may use a piece of yarn or string cut to the length of your unit to make the measuring easier.)

Procedure:
Measure the following, using the unit indicated:
• the width of the shelves in cubits
• the width (front to back) of your book in digits
• the width of the window in spans
• the height of the desk in feet
• the length of the room (front to back) in paces

Data: Record your answers in a data table and compare your data with the data of 3 more students

Conclusion:
1. What problems do you see with these measures?

2. What would you suggest doing to make these measurements more accurate?

Marshmallow Lab

2009-03-03T15:39:00.006-05:00

Physical & Chemical Changes

Purpose: To introduce physical & chemical changes.

Background info: A physical change forms no new substance. It merely changes the shape, form, or state of a material. Examples: evaporating water, melting of ice, freezing of water, moving an object or others mentioned in your text.
A chemical change forms one or more new substances. Some familiar chemical changes: burning of gas, oil, coal, or paper; digestion, the souring of milk, the rusting of iron (more mentioned in your text). Chemical changes usually involve heat, burning, or some interaction with energy. Chemical changes are either endothermic (absorb heat energy) or exothermic (give off heat energy). A chemical change makes new compounds.
There are 5 ways to tell if a chemical reaction has occurred:
1. A change in color appears.
2. Gases are given off.
3. A new substance forms.
4. Heat is given off (exothermic).
5. Heat is required (endothermic).
Sometimes you can see only one of these, sometimes several.

Equipment: Bunsen burner, matches, goggles, marshmallow, skewer.

Procedure:
1. Tear a marshmallow in half.
2. Eat the marshmallow.
3. Follow the instructions for properly lighting a Bunsen burner. Then put another marshmallow on a skewer and hold it over the Bunsen burner until it is golden brown.

Data:
1. What type of change occurred in #1 above?_____________________

2. What type of change occurred in #2 above? ____________________

3. What type of change occurred in #3 above? ____________________

Circle YES if it is a chemical change and NO if it is not.

1. Water Evaporating YES NO

2. Log Burning YES NO

3. Mixing Sugar into Tea YES NO

4. A Car Rusting YES NO

5. Ice Melting YES NO

6. Boiling Away a Liquid YES NO

7. Milk Going Sour YES NO

8. Digesting Food in your Stomach YES NO

9. Making Sugar into Caramel YES NO

10. Roasting a Marshmallow YES NO

Conclusion:

Explain the difference between a physical and a chemical change. Include some examples. (At least one paragraph)