Materials for Life

1
Materials for Life
NBSP Physical Science Leadership Institute

• Professor Lynn Cominsky
• Joanne del Corral
• Sharon Janulaw
• Michelle Curtis
• July 9, 2003

2
Standard Connections

• Students know properties of solid, liquid and
  gaseous substances, such as sugar (C6H12O6),
  helium (He), and Oxygen (O2), nitrogen (N2) (5)
• Students know the common properties of salts,
  such as sodium chloride (NaCl) (5)

3
First Activity Sugar and Salt

• How are sugar and salt different?
• If we couldnt taste them, how could we tell
  which is which?

4
Sugar and salt investigations

• Given quantities of sugar salt, and all the
  equipment that you have been using during the
  past two weeks
• Can you predict how the physical properties of
  sugar and salt might differ?
• Can you design experiments to differentiate
  between sugar and salt?

5
Key concepts about Sugar

• Sugar is a type of carbohydrate and the most
  common molecules found in plants and animals
• Carbohydrates are literally Carbon that is
  hydrated ? Carbon water
• C6H12O6 is glucose
• Other common sugars
• sucrose C12H22O11
• fructose C6H12O6
• All sugar names end in ose as do other
  carbohydrates

6
Structure of Glucose
7
Key concepts about Salt

• In its simplest form, Salt is a molecule that
  pairs one element from the first group in the
  periodic table (e.g., Na) with an element from
  the seventh group (e.g., Cl)
• Group 1 elements have one unpaired electron in
  their outer shells, while Group 7 elements are
  missing an electron to complete their outer
  shells

8
Key concepts about Salt

• Salts can be formed by mixing an acid and a base
  to form a salt and water
• For example Hydrochloric acid Sodium
  Hydroxide? table salt water
• HCl NaOH ? NaCl H2O
• In solutions, salt dissociates into Na and Cl-
  ions
• Na has lost one electron
• Cl- has gained one electron
• Ionic solutions can conduct current

9
Structure of NaCl
10
Second activity Comparing gases

• Helium, Nitrogen and Oxygen are all commonly
  occurring gases
• Consult the periodic table to compare the
  properties of these gases
• Can you draw pictures of the structure of each
  gas?
• Consult the materials in your binder to compare
  the uses of these gases

11
Key concepts Common gases

• Helium is a Noble gas it is the second most
  common element in the Universe but is only
  present in trace amounts in the Earths
  atmosphere
• Nitrogen and Oxygen are diatomic gases which are
  rare in the Universe but
• 78 of the atmospheric volume is nitrogen
• 21 of the atmospheric volume is oxygen
• They are both very chemically reactive

12
Structure of Common GasesN2

• Nitrogen gas is a diatomic molecule formed from
  two atoms of Nitrogen.
• Each atom has 7 electrons.
• The inner shell is filled with 2 of these
  electrons, leaving a total of 5 electrons that
  try to fill the next shell (which holds 8) for
  each atom.
• A triple covalent bond between the two nuclei
  shares 3 pairs of the electrons.
• Two other electrons are individually bonded to
  each nucleus.

13
Structure of Common GasesO2

• Oxygen gas is a diatomic molecule formed from two
  atoms of Oxygen.
• Each atom has 8 electrons.
• The inner shell is filled with 2 of these
  electrons, leaving a total of 6 electrons that
  try to fill the next shell (which holds 8) for
  each atom.
• A double covalent bond between the two nuclei
  shares 2 pairs of the electrons.
• Four other electrons are individually bonded to
  each nucleus.

14
Vocabulary

• Salt ionic molecule that pairs a group 1 and a
  group 7 element
• Sugar molecule that combines Carbon with an
  integral number of water molecules
• Ion elemental form with extra or missing
  electrons
• Noble gas an element in Group 8, which has a
  filled outer shell and is chemically (rather)
  inert

15
ELD Activities Visual Imagery

• Make a slide show, or have images ready to show
  to the students.
• Ask them to first write down on a piece of paper
  or in their journal whether the object shown is a
  liquid, a solid, or a gas.
• Then ask volunteers to give their answer.

16
Publishers Materials

• Take some time to look through the state-adopted
  texts to find activities relating to commonly
  occurring substances, such as sugar, salt and
  atmospheric gases

17
Break something to think about

• Why do you think the relative abundances of
  helium vs. nitrogen/oxygen are so different
  between the Universe and the Earths atmosphere?

18
Standard Connections

• Students know atoms and molecules form solids by
  building up repeated patterns, such as the
  crystal structure of NaCl or long-chain polymers.
  (8)

19
Third Activity Structure of Solids

• Given toothpicks, styrofoam balls
• Use the toothpicks to represent electrons in the
  outer shells
• Use the styrofoam balls to represent the nuclei
  of the various elements
• Create models for NaCl, Glucose, Nitrogen gas and
  oxygen gas
• Compare the models what are the structural
  differences between Sugar and Salt? Between N2
  and O2?

20
Key concepts Structure of Sugars

• Sugars come in many forms
• Monosaccharides glucose, fructose
• Disaccharides - sucrose
• Polysaccharides made of many smaller glucose
  type rings
• Polysaccharides include starch, glycogen and
  cellulose

21
Structure of Solids Polymeric Molecules

• Starch is made of many units of glucose
• Numbered corners are C-H (not shown)
• This is (a small part of) amylose ? 4000 units of
  glucose

22
Further investigations Slime!

• Given Borax, white glue, water, food coloring,
  ziploc bag
• Add 1 Tbsp. Borax to 1 cup water, stir until
  dissolved
• Make a solution of ¼ cup water and ¼ cup glue
  mix thoroughly
• In a ziploc bag, add equal parts borax solution
  and glue solution
• Add a couple of drops of food coloring
• Seal bag and knead mixture
• Dig in and have fun!

23
Further questions

• What are the properties of slime?
• How can we tell that this is a polymer?
• What other polymers do you know?

24
Key concepts Structure

• Ionic crystals such as salt, have a regular
  lattice structure
• Repeating units in salt are cubic in shape the
  molecule is also cubic
• Sugars have units that can repeat to make complex
  carbohydrates such as starch
• Repeating units are cyclic in shape the overall
  molecule is chain-like

25
Vocabulary

• Polymer complex molecule made of repeating
  units in a chain-like structure
• Crystal molecular structure made of repeating
  units in a cubic structure
• Saccharide sweet substance
• Starch polysaccharide that is used for energy
  storage in plants
• Glycogen polysaccharide that is used for energy
  storage in animals

26
ELD Activities Analogies and Student Involvement

• Have the students investigate their favorite food
  and snacks.
• Ask them to look at the Ingredient List on the
  label of the food packaging and list all the
  words ending in ose in their journal.
• Go over the words with them the next day. (A hint
  on health awareness might be welcome there as
  well!)

27
Publishers Materials

• Take some time to look through the state-adopted
  texts to find activities relating to structure of
  common molecules
• Examples MH p. 221

28
Lunch some things to think about

• How do sugars and starches provide energy for
  plants and animals?

29
Standard Connections

• Students know how to determine whether a solution
  is acidic, basic or neutral (8)

30
Fourth Activity Cabbage Juice Science

• Make your own acid/base indicator by boiling red
  cabbage.
• Use the juice to test whether different fluids
  are acids or bases.
• Compare the pH results from the cabbage juice to
  those obtained using litmus paper.

31
Equipment for Cabbage Juice activity

• red cabbage juice
• vinegar and lemon juice
• baking soda, powdered lime, and liquid soap
• some plastic spoons, stirring sticks, and 4
  plastic cups
• 5 medicine droppers
• 1 marker

32
Cabbage Juice Activity

• Label 6 clear plastic cups with numbers 1-6
• Fill all cups up 1/4 of the way with cabbage
  juice.
• Collect your five samples
• Vinegar
• Lemon juice
• Baking soda
• Powdered lime
• Liquid soap (non-antibacterial)
• Place a small amount of each sample into each of
  five of the plastic cups.
• If your sample is an acid, it will turn the
  cabbage juice pink. If your sample is a base, it
  will turn the cabbage juice green.

33
Further investigations

• Label 2 clear plastic cups 1 and 2
• Fill all cups up 1/4 of the way with water.
• Place one known acid and one known base into each
  of the cups.
• Place a piece of litmus paper into each of the
  cups.
• Basic solutions will turn red litmus paper blue
  and will leave blue litmus paper unaffected.
• Acidic solutions will turn blue litmus paper red
  and will leave red litmus paper unaffected.

34
Key concepts pH

• Acidic solutions contain an excess of protons or
  H. pH is a measure of how 'acidic' a solution
  is. The lower the pH, the more acidic the
  solution.
• In chemical terms, pH means "the negative log of
  the concentration of protons" in solution.
  Chemistry students should recognize this as pH
  -logH.

35
Key concepts pH

• "Neutral" solutions (e.g.,water) have a pH of 7.
  This number coincides with the amount of H
  naturally formed in water from the equilibrium
  reaction
• H2O ?? H OH-
• "Basic" solutions have a pH greater than 7,
  meaning that they have less free H than that in
  neutral water.

36
Key concepts pH

• Red cabbage contains pigments call anthocyanins.
  The pigments give it the red/purplish color.
  Anthocyanins belong to group of chemical
  compounds called flavonoids.
• Other plants that contain anthocyanins include
  beets, cranberries and blueberries.

37
Vocabulary

• pH A measure of the acidity or alkalinity of a
  solution, numerically equal to 7 for neutral
  solutions. The pH scale commonly in use ranges
  from 0 to 14.
• Base Any of a class of compounds whose aqueous
  solutions are characterized by a bitter taste, a
  slippery feel, the ability to turn litmus blue,
  and the ability to react with acids to form
  salts.
• Acid Any of a class of substances whose aqueous
  solutions are characterized by a sour taste, the
  ability to turn blue litmus red, and the ability
  to react with bases and certain metals to form
  salts.

38
ELD Activities Visual imagery and student
involvement

• Form groups of 14 students.
• Have all students wear an H sign.
• Draw a circular boundary (one per group) on the
  ground and ask each group to make acidic,
  neutral, or basic solutions by adding, or
  removing Hs (represented by each student) using
  the pH scale as a reference.

39
Publishers Materials

• Take some time to look through the state-adopted
  texts to find activities relating to pH, acids
  and bases.
• Examples HM p. C78

40
Break some things to think about

• Do you think pH would be a useful test to
  discriminate between sugar and salt?
• Why or why not?

41
Standard Connections

• Students know living organisms and most materials
  are composed of just a few elements (5)

42
Fifth Activity Essential elements in living
organisms

• Review the handout in the binder that includes
  many tables summarizing the elemental abundances
  in different locations
• How many elements are essential to plants? To
  animals?
• How do the abundances change from the Universe to
  the solar system?

43
Fifth Activity Essential elements in living
organisms

• How do the abundances change from the solar
  system to the atmosphere?
• How do the abundances change from the atmosphere
  to the oceans?
• How do the abundances change from the oceans to
  the crust?
• How do the abundances change from the crust to
  plants?

44
Further investigations

• What do these changes tell you about the
  evolution of life in the Universe?

45
Key concepts Essential Elements

• Light elements (H and He) dominate the early
  Universe
• As the solar system formed, heavier elements
  (made in stars) were incorporated to make the
  planets
• The atmosphere is about ¾ N2 and ¼ O2
• There are a limited number of elements that are
  essential to plants and animal life, including H,
  C, N and O.

46
Vocabulary

• Abundance relative amount of an element

47
ELD Activities Compare and Contrast Table A
Write down examples of living organisms. Remember you are a living organism! Find or draw a picture of the living organisms you found List all elements this organism or material needs in order to survive (i.e. water)


48
ELD Activities Compare and Contrast Table B
Write down examples of materials Find or draw a picture of the materials you found List all elements this organism or material needs in order to keep form (i.e. Carbon)


49
Questions for ELD Tables

• 1. Using table A and B, list the common elements
  you see in living organisms and materials
•  
• 2. What does this tell you about living organisms
  and most materials? Are they similar in any ways?

50
Publishers Materials

• Take some time to look through the state-adopted
  texts to find activities relating to the elements
  that are essential to plants and animals

51
Take away brain teaser

• What do you think the gases are that make up the
  atmospheres of the gas giant planets such as
  Jupiter and Saturn?

52
Lesson Study Activities

• Identify a key concept from todays lecture for
  further development
• Review the publishers materials about this key
  concept
• Think about the best way to present this key
  concept in your classroom

53
Resources

• Physics by Inquiry L. McDermott and the PEG at
  U Washington
• http//www.saltinstitute.org/15.html
• http//www.brooklyn.cuny.edu/bc/ahp/SDPS/SD.PS.ion
  s.html
• http// biology.clc.uc.edu/graphics/
  bio104/glucose20alone.jpg
• http//www.greenspirit.org.uk/resources/glucose.gi
  f
• http//www.elmhurst.edu/chm/onlcourse/chm110/moli
  mages/N2.GIF
• http//www.poemsinc.org/oceano/abund.htm