Checking in!
This was a slogan
from 1950’s
when chemists
first developed
plastics, food
additives, and
new prescription
drugs.
Is your life better because of chemistry?
Explain your answer in your lab book.
Chapter 1 –
The Chemical World
Introduction to Chemistry
Demo: Why study
Chemistry?
•
Make a sketch of the set up in your lab
book.
• Listen to the story and record your
observations as changes occur.
Conclusions
1. What does “act upon” mean?
2. Do you agree with Ira Remsen’s
statement that the only way to learn
chemistry is to do experiments? Explain
What most people think
of as doing chemistry…
• ..\..\Videos\RealPlayer
Downloads\Mr Bean - Chemistry
experiment - YouTube.flv
Why study chemistry?
• Chemistry is the study of matter and
its changes.
• Matter is anything that has mass and
takes up space.
• What isn’t matter?
Why study chemistry?
There are two major ways to study
chemistry.
1. Pure or Theoretical Chemistry –
the study of chemistry for new
knowledge.
2. Applied or Practical Chemistry –
the study of how to use chemical
information to solve a problem or
create new materials (Technology)
Pure vs. Applied Chemistry
• What is the difference?
• Profile of Bonnie Bassler
• http://www.pbs.org/wgbh/nova/searc
h/results/?q=archive
Why study chemistry?
The five branches of chemistry:
Chemistry
Inorganic
Organic
Biochemistry
Physical
Analytical
Why study chemistry?
• Chemists design materials to fit
specific needs (plastics, alloys)
• Chemists design new fuels to
produce or store energy (batteries,
solar power )
• Chemists develop new medicines
and medical tools (insulin, insulin
pumps)
Why study chemistry?
• Chemists help to develop more
productive crops in agriculuture
(pesticides, hydroponics)
• Chemists help to identify pollutants
in the environment (lead in paint,
DDT, CFC’s and the ozone layer)
• Chemists help to identify materials
that are found in the universe (star
composition, water on Mars)
It’s good to know
chemistry…
• You never know when it will come in
handy!
• Beauty and Brains
Why study chemistry?
• Problems with oil in your water? How the
oil has spread since the original accident.
• Photos of the coast taken by NASA.
• Make observations about the solution of
oil in water on the demo table.
• Can you find a way to remove the oil?
• HW: Research methods available to
remove oil from water, and bring your
idea tomorrow. We will choose 4
methods to try.
Activity: Oil Spill Clean
Up
• Chemistry can be used to solve
problems such as the oil spill
• What ways have they used to clean
up the oil spill? List them.
Method
Rating Scale
Checking In!
• Get a copy of the article and read
about oil eating bacteria.
• Why is the oil eating bacteria a good
solution to the oil spill clean up?
• What other methods are available?
Lab: The Cat’s Meow – does
changing the liquid affect the
reaction of detergent?
1.
2.
Measure 10 ml of whole milk and pour into a
Petri dish.
Add one drop of each color of food coloring to
the milk.
R
B
Y
G
3.
4.
5.
Dip a toothpick into detergent and place in the
center of milk.
Make observations.
Repeat with skim milk, then with water
Lab: The Cat’s Meow
1. Make a table to list observations of
the changes in the colors in the
whole milk, skim milk, and water
(or any other liquid you tried).
2. What conditions stayed the same
each time you did the experiment?
3. What condition changed each time
you did the experiment?
Lab: The Cat’s Meow!
4. How did you measure or record the
outcome of the experiment?
5. Refer back to the question asked in
at the beginning of the lab. What
do you think? Why?
Experimental Design
• Make an observation either
qualitative (words) or quantitative
(numbers).
• Form a hypothesis (educated guess)
• Design an experiment to test
hypothesis
• The test should have only one
variable (independent variable) or
condition that is changed.
Experimental Design
• The test should include a way to
measure the outcome of the
experiment (dependent variable)
which is the responding variable.
• All of the other conditions must stay
the same (constants).
• A control group can be used as a
means of comparison.
Experimental Design
• Analyze the data and make
calculations.
• Draw a conclusion which either
supports or rejects the hypothesis.
• Repeat the experiment to verify the
results.
• Alter or accept the hypothesis.
Experimental Design
•
•
•
•
•
•
Reflect about the Cat’s Meow lab.
What was the independent variable?
What was the dependent variable?
What were the constants?
Was there a control group?
What other variables could be
tested?
Quiz: Identify the independent and
dependent variable in each case.
1. Crickets were placed in tanks of
different temperatures and the
number of chirps by the crickets
were counted.
2. Moths were placed in a tank that
contained three different colors of
light bulbs. The number of moths
that swarmed around each light
were counted to see which color
attracted the most moths.
Quiz continued
3. Three different brands of microwave
popcorn were popped for three
minutes in the same microwave.
Then the bags were opened and the
number of un-popped kernels were
counted to see which brand popped
the most.
Experimental Design
• Once hypotheses have been tested
repeatedly, they may become
scientific laws.
• A scientific law is a short statement
that describes a phenomenon, but it
does not try to explain it.
• Example, Law of Conservation of
Matter states, “Matter cannot be
created or destroyed only changed
in a chemical reaction.”
Experimental Design
• Scientific Theories are broad
explanations based on extensively
tested ideas and supported by data.
Theories are constantly revised as
new information is learned.
• Example: Atomic Theory which
explains the structure of the atom
and has been modified over many
years.
Experimental Design
Experimental Design
Identify the IV, DV, and constants in the
following experiment:
Ann wanted to test which brand of antacid
neutralized the most stomach acid. She
tested 3 different solid brands by crushing
a tablet of each and weighing out 10 g of
antacid. Then she dissolved it in 25 ml of
water, and titrated it with 3 M hydrochloric
acid to simulate stomach acid. She
recorded how much acid was needed to
neutralize each tablet.
Making Line Graphs
1.
2.
3.
Place independent variable on X axis.
Place dependent variable on Y axis.
Determine an appropriate scale for each axis
based on the range of data. X axis may be
different than Y axis.
4. Always number from zero .
5. Number axis in consistent manner (by 2’s, 5’s,
etc) with no breaks in the numbering.
6. Plot points.
7. Circle the data points.
8. Draw line of best fit, if linear, or follow curve, if
exponential.
9. Label each axis with name and units of
measure.
10. Give graph an appropriate title.
Lab Activity: Determining
Height from Foot Size
• Measure your foot size and height
and record them in the chart.
• Then compare data with 10 friends
foot size (cm)
height (cm)
Lab Activity: Determining
Height from Foot Size
•
Make a graph of foot size on X axis
and height on Y axis.
• Circle points. Draw line of best fit.
Conclusions
1. Describe the shape of the graph.
2. Is there a relationship between foot
size and height? Describe it.
Activity: Science Never
Sucks!
• Set up the experiment as described
on your handout.
• What did you observe? Can’t use
the word “suck!”
Theory of Phlogiston
Modern Theory of
Burning
Checking In:
Bazooka Joe’s
Hubba Bubba
Bubblicious
Study the picture and identify the independent and
dependent variables. Name 2 constants that are needed.
Lab: You don’t have to
count your pennies!
Purpose: To determine the relationship between
the number of pennies in a sample and the
mass.
# of Pennies
0
1
3
5
7
10
Roll of 50
Mass (g)
0.00
Lab: You don’t have to
count your pennies!
# of pennies
0
1
2
5
7
10
roll of 50
Mass (g)
0.00
Thickness (mm)
0.0
Conclusions:
1. What was the independent and
dependent variable?
2. Describe the shape of the graph.
3. What errors could exist in your
measurements?
4. What was the mass of the sample
of pennies? How many pennies
should be in the sample?
5. How could the data be useful in
everyday life?