Hands-on experiment or
experiment design challenges
Relevance to real world (Core
ideas for STEM MS course)
Demonstrated scientific principles
1) Sand/Salt Mixture
Recycling – chemical
separations by solubility
 solubility of different rocks in water
depends on their chemical composition
 Solubility of a salt is possible because of the
ionic character of salt
 The possibility of forming hydration shells
around anions and cations which is based on
the ability of polar water molecules to have
dipole-dipole interactions with the ion
 in contrast, sand is SiO2 which consists of a
network of covalent bonds
 covalent bonds and cannot be broken by
neutral water at normal temperature
 ionic bonds can sometimes be broken by
normal water at room temperature, in
particular, when the dissolved species are
more energetically favorable than the solid
How can you separate the two
components of the mixture?
Materials: fine sea sand, salt, cups
for making solution and decanting
More Info:
http://www.nuffieldfoundation.org/
practical-chemistry/separating-sandand-salt
The link provides many suggestions
for working with chemistry-specific
equipment, e.g. a Bunsen burner.
However, the salt can also be
extracted from the mixture by using
tap-warm water and does not
necessarily require a burner.
2) Mixed Confetti
If you had a large amount of these
confetti, could you sort them and
sell them repackaged?
Why seashores are salty and
sandy – rocks that dissolve in
water dissolve and make it
taste salty; others just get
ground up by the forces of
waves and end up to be sand
 materials with higher density than the
surrounding medium sink to the bottom of a
suspension
 materials with a lower density than the
surrounding medium swim on the top of the
Recycling – density separations
of different materials in
municipal waste
Swimming islands – density of
1
Connection to Next
Generation Science
Standards
HS-PS1-3, HS-ESS2-5,
HS-ESS3-2
Chemistry, 6 – 8
8. Differentiate
between mixtures
and pure substances.
Chemistry, High
School
4.1 Explain how
atoms combine to
form compounds
through both ionic
and covalent bonding.
Predict chemical
formulas based on
the number of
valence electrons.
4.5 Identify how
hydrogen bonding in
water affects a
variety of physical,
chemical, and
biological phenomena
(e.g., surface tension,
capillary action,
density, boiling point)
HS-PS1-3, HS-ESS23, HS-ESS3-2
Chemistry, 6 – 8
2. Differentiate
between volume and
plastics is lower than the
density of water => islands of
plastic waste form in the sea in
areas of minimal currents
medium
 examples: oil on water, stones on the
bottom of rivers, fuel on water
 this behavior can be used to separate
different materials and chemicals from each
other despite the fact that they might be
mixed in municipal waste
 even different plastics can be separated
from each other based on their different
densities, using liquids of different densities,
e.g. water, saline, alcohol and mixtures
thereof
3) Elephant’s toothpaste
Catalysis and Biocatalysis
Materials: low-percentage hydrogen
peroxide (grocery store- can be
higher percentage if for
demonstration), empty soda bottles,
dry yeast, food coloring, liquid dish
soap
How chemical reactions are
happening in your body – the
list of them is endless!
 The reaction that is observed is the
decomposition of H2O2 (hydrogen peroxide)
 Hydrogen peroxide is used to bleach hair
and as an antibacterial agent – therefore,
one can buy it at the supermarket; maybe
some of the students are familiar with the
bubbling contact lense solution which is also
based on H2O2 decomposition
 The products of the reaction are oxygen O2
and water H2O
 Without the presence of the catalyst, H2O2
is fairly stable and decomposes very slowly
 With the presence of yeast, the
decomposition reaction gets really fast and
H2O and O2 are formed very quickly
 The bubbles seen as foam are oxygen in a
detergent bubble
Materials: hole puncher or scissors,
plastic foil (PE or PP), aluminum
metal foil, see-through cups, salt,
spoons
More info:
http://www.teachersource.com/pro
duct/mixture-separationchallenge/density
Every molecule in living
organisms has been made
through catalysts
More Info:
http://www.stevespanglerscience.co Catalysts can make and break
m/experiment/elephants-toothpaste bonds
Catalysts allow chemical
reactions at lower temperature
but do not change the overall
energetics of a reaction
2
mass. Define density.
Chemistry, High
School
1.1 Identify and
explain physical
properties (e.g.,
density, melting
point, boiling point,
conductivity,
malleability) and
chemical properties
(e.g., the ability to
form new
substances).
Distinguish between
chemical and physical
changes.
PS1.B, HS-ESS3-4
Chemistry, High
School
5.2 Classify chemical
reactions as synthesis
(combination),
decomposition, single
displacement
(replacement), double
displacement, and
combustion.
 Yeast has an enzyme in its cell that catalyzes
the decomposition of H2O2, because free
H2O2 can be dangerous to living cells and
result in cell death
 Therefore, yeast can stay alive even in the
presence of H2O2
 Some bacteria don’t have an enzyme that
catalyzes the decomposition reaction, and
can therefore be destroyed either by the
product oxygen or by H2O2 itself –
therefore, H2O2 has an anti-bacterial effect
without being toxic to humans
 CO2 is dissolved in water as gas (with just
small interactions with water) or as carbonic
acid H-O-C(=O)-O-H (which is a molecule
with completely different arrangement of
bonds) to make soda water
 Carbonic acid is the reason why soda water
tastes slightly sour
 Carbonic acid also has a preserving effect, as
bacteria growth is slower due to the acid
around
 When crystalline sugar (or mentos covered
with crystalline sugar) are placed into soda,
the physically dissolved CO2 and the
carbonic acid both decompose to gaseous
CO2 on the surface of the crystalline
material
 It’s important to note that the OH groups in
sugar are important for this process and
catalyze it through the formation of
hydrogen bonds between the OH of the
sugar and the dissolved CO2 or the carbonic
acid O atoms
Catalyzed reactions are
typically more sustainable
reactions, b/c they don’t need
“extra energy” which is the
activation energy
4) Soda volcano
Materials: soda (smaller bottles
work better; diet soda works just the
same a regular soda, but is not a
sticky), mentos (for demonstrator)
or crystal sugar (for students)
Surface Catalysis or why soda
water is bubbly
So called solid catalysts are
used very widely in the
chemical industry, especially to
make fuel out of crude oil
More Info:
http://www.sciencebuddies.org/sc
ience-fairprojects/project_ideas/MatlSci_p0
23.shtml#background
3
PS1.B, HS-ESS3-4
Chemistry, High
School
7.3 Identify and
explain the factors
that affect the rate of
dissolving (e.g.,
temperature,
concentration,
surface area,
pressure, mixing).
7.5 Identify the
factors that affect the
rate of a chemical
reaction
(temperature, mixing,
concentration,
particle size, surface
area, catalyst).
5) Milk Rainbows
Biodegradation
Materials: flat dish, food coloring,
liquid dish soap, cotton swab
Milk is a typical example of a
biological solution: very
complex, based on water,
solubility and surface tension
are well defined
More Info:
http://www.stevespanglerscience.co
m/experiment/milk-color-explosion
 Milk is a pretty complex mixture of soluble
proteins, fat, vitamins, and minerals
 This mixture has a certain miscibility,
density, solubilizing behavior, and surface
tension which is unique to its composition
 All these characteristics are unique to milk
and the fact that the food coloring does not
distribute by itself is a consequence of the
different characteristics of the food color
which is typically just a solution of the
coloring chemical in plain water
 Detergents, one the other hands, are
typically well defined and chemically pure
substances that have the structure of a
carbon chains of 10 to 25 carbon atoms that
is attached to a polar group, e.g. a sulfonate
or a carboxylate
 These hydrophobic (carbon chain) part of
the detergent molecules strive to associate
with fat molecules in milk which are also
hydrophobic
 The polar groups which are hydrophilic
strive to associate with water as water is the
most hydrophilic compound in milk
 Once the detergent is added into the
mixture, the detergent molecules “race”
through the milk to find available fat
molecules to associate with
 This motion causes the a “stirring” in the
milk that also stirs the aqueous solution of
the food coloring
 Water molecules H2O are very polar with a
slightly positive charge at the H atoms and a
slightly negative charge at the site of the O
Detergents fundamentally
change the solubility behavior
of milk and most other
“natural” liquids like fresh
water and seawater
Detergents outside of a closed
waste-water system (e.g. using
non-biodegradable soap when
camping) can have
unpredictable consequences
for life in water due to the
changed properties of aqueous
solutions in the presence of
detergents (e.g. “foaming” in
streams and waterfalls)
6) Floating on Water
Biodegradation
Materials: flat dish, water, liquid
Surface tension influences the
4
HS-LS2-6
ETS1.B
Chemistry, High
School
7.4 Compare and
contrast qualitatively
the properties of
solutions and pure
solvents (colligative
properties such as
boiling point and
freezing point).
HS-LS2-6
HS-ESS3-4
ETS1.B
dish soap, pepper
http://chemistry.about.com/od/che
mistrymagic/a/peppertrick.htm
http://drholly.typepad.com/ask_me
_a_chemistry_questi/2006/01/pepp
er_and_soap.html
Could be transformed into an inquiry
activity testing a variety of different
liquids and floating items
ability of water bugs and other
items to be present on the
surface of water without falling
in.


Therefore, molecules that
change this surface tension, socalled surfactants, can be toxic
to whole ecosystems, if not
biodegradable.

Some surfactants are biodegradable and will thus lose
their ability to act as
surfactants when exposed to
microorganism and/or air.






7) Feel the energy!

Energy
5
atom
This leads to the water molecules
interacting very strongly so that the O points
towards the H atoms of surrounding
molecules and vice versa
water molecules want to interact with each
other much more than they want to interact
with the molecules in air which are nonpolar
when looking at drops, it seems that water
tries to minimize the area that is exposed to
air, which is much better in a circular ball
shape than in a flat shape like a disc
Physicists have called this phenomenon
“surface tension” , as the tendency of the
surface of a liquid that allows it to resist an
external force
When adding detergent to the water, the
detergent molecules mix with water and
disrupt the interactions between the H2O
molecules as they mix
As a consequence of this mixing, the surface
tension becomes much lower
This in turn causes the water to spread out
as a disc shape becomes now more
favorable than a round shape
This spreading out motion is followed by the
pepper that swims on the surface of the
water and some pepper might start to sink
Similar experiments can be even done with
small metal paper clips that swim on water
as long as no detergent is present and sink
once detergent is added
Chemical reactions can cause release energy
4.5 Identify how
hydrogen bonding in
water affects a
variety of physical,
chemical, and
biological phenomena
(e.g., surface tension,
capillary action,
density, boiling
point).
HS-PS1-5,
Materials: plastic cup, baking soda,
vinegar

When vinegar and baking soda
react, you can feel the heat –
and see the movement!
http://www.instructables.com/id/Ba
king-soda-Vinegar-experiment/
or
http://www.sciencekids.co.nz/experi
ments/vinegarvolcano.html



8) Blubber gloves
Materials: ziplock bags, duct tape,
shortening, spoon, water, ice,
bucket

Energy – building insulations,
insulation of animals in the
arctic, insulation of reactors in
the chemical industry


http://www.stevespanglerscience.co
m/content/experiment/blubbergloves



6
to the environment
The released energy can be observed in
different ways: heat (thermal energy),
movement of molecules/particles (kinetic
energy), waves (in the visible, infrared or UV
spectrum)
Whenever energy can be released into the
environment, a chemical reaction is in
principle feasible and want to occur – but
sometimes they don’t
This phenomenon is called “activation
energy” – similar to a stone on the top of a
mountain that needs to overcome a little
barrier to be able to roll down
Examples are combustion of paper – it is a
readily occurring reaction when the
activation energy is overcome by adding a
flame, but without a spark nothing happens
Thermal energy is transferred from one item
to the next by movement of molecules
The hotter the temperature, the faster is the
molecule movement
Water is very good at conducting this
thermal energy because the density of
molecules in water is very high
all molecules in water form a network
through hydrogen bonds & dipole-diploe
interactions that can conduct changes in
motion very quickly
when our hands touch objects the slowing
down of the motion of our own molecules in
our skin is interpreted by our neurons and
brain as “cold”
Fat, in contrast to water, has much smaller
HS-PS3-2
Chemistry, High
School
6.4 Describe the law
of conservation of
energy. Explain the
difference between
an endothermic
process and an
exothermic process.
HS-PS3-1
HS-PS3-4
Chemistry, High
School
6.3 Using the kinetic
molecular theory,
describe and contrast
the properties of
gases, liquids, and
solids. Explain, at the
molecular level, the
behavior of matter as
it undergoes phase
transitions.


9) Taco Sauce Penny Cleaner

Sustainable Feedstocks
/Catalysis

Which components or mixtures of
components in Taco sauce are doing
the trick?

Materials: dirty pennies, Taco sauce
(mild sauce from Taco Bell works
well), vinegar, tomato sauce, salt,
water, small plates

http://www.stevespanglerscience.co
m/experiment/the-cleaning-powerof-taco-sauce-bright-shiny-pennies




7
interactions between the molecules –
therefore, molecular motion (=heat) cannot
be transported as fast and efficiently
Therefore, having a layer of fat between
your hand and cold water insulates your
neuron from detecting the slower molecular
motion on the other side of the barrier
The dark tarnish on metal items like pennies
consists mostly of metal oxides
In the case of pennies, the tarnish is Cu(II)O,
which is formed by reaction of oxygen with
the copper metal that forms the outer, red,
and shiny layer of pennies
Because both vinegar and salt are needed to
clean the penny (=dissolve CuO), both
ingredients have to be accounted for in the
reaction equation
The effect of vinegar is expressed by its
dissociation into proton H+ and acetate
anions
2 H+ react with the oxide ion in CuO to form
one equivalent of water H2O; however, this
is a slow reaction
The chloride ions in salts coordinate to the
copper and CuO on the surface of the penny
and help to make and intermediate [CuCl2]The formation of [CuCl2]- is very fast; then
[CuCl2]- can be oxidized to Cu2+ in solution
by the oxygen in air
The reaction through [CuCl2]- seems to be
more complicated than just the reaction of
CuO with H+, but it is much faster and
therefore one can say that chloride Clenables the reaction and acts as a catalyst
HS-PS1-1
HS-PS1-4
HS-PS1-6
PS1.B, HS-ESS2-6
Chemistry, High
School
5.2 Classify chemical
reactions as synthesis
(combination),
decomposition, single
displacement
(replacement),
double displacement,
and combustion
8.4 Describe oxidation
and reduction
reactions and give
some everyday
examples, such as
fuel burning and
corrosion. Assign
oxidation numbers in
a reaction.
10) Caramel!!!
Sustainable Feedstocks
Materials: sugar, water, cooking pot,
hotplate/oven or crockpot (make
sure nothing overcooks – otherwise
things get a little sticky – hot water
typically dissolves all residues)
Most feedstocks in nature
(sugar, starch, cellulose) are
made of such networks for a
good reason: plants and
animals don’t want to be
dissolved when they get rained
on!
http://chemconfections.blogspot.co
m/2011/01/caramel-deliciousscience-experiment.html
or
http://sciencegeist.net/thechemistry-of-caramel/
 Caramel is a well-known additive for food
 When looking at the sum formula of caramel
versus normal sugar, there is very little
difference
 When looking at the actual structure of the
molecules in these two solids there is a
significant difference
 This difference is easily detectable just by
investigating the consistencies of caramel
versus sugar and also by the different colors
 Then – what happens when you make
caramel from sugar?
 Sugar consists mainly of units of six carbon
atoms (glucose or fructose), no matter from
which plant is has been made (sugar cane,
sugar beets, or corn)
 Sometimes, these units are combined into
molecules consisting of two C6 units
 This combination of two C6 units is called a
“dimer” – two “monomers”
 Every time one monomer links to another
one, one molecule of water is produced as
byproduct of the reaction: 2 C6H12O6 ->
C12H22O11 + H2O
 When you make caramel, many of these so
called “condensation reactions” take place,
so that the final product consists of a
network of many monomers, which is called
“polymer” that we can imagine as
interlinked chains of monomers
 This polymeric structure explains some of
the physical properties, in particular the
hardness of caramel – as it consists of many
covalent bonds, it takes a very strong force
Therefore, one of the
challenges for us humans when
using these feedstocks e.g. as
“biofuels” or as feedstocks for
the pharmaceutical or
materials industry is how to
break the polymers up into
monomers that can be handled
easily (like crystal sugar)
8
HS-PS1-3
HS-PS1-5
HS-LS1-7
HS-LS1-5, HS-LS1-6,
HS-LS2-4
Biology, High School
1.2 Describe the basic
molecular structures
and primary functions
of the four major
categories of organic
molecules
(carbohydrates, lipids,
proteins, nucleic
acids).
Chemistry, High
School
5.2 Classify chemical
reactions as synthesis
(combination),
decomposition, single
displacement
(replacement),
double displacement,
and combustion.



11) Hard liquids
Sustainable Materials
Materials: cup, corn starch, water,
spoon, maybe food coloring (more
fun!)
Starch is a molecule which can
be digested by humans and has
a chain-like structure with
some branching that leads to
forming networks
More Info:
http://scifun.chem.wisc.edu/homee
xpts/lumpyliquids.htm
or
http://www.stevespanglerscience.co
m/experiment/quicksand-goo



The common formula for starch
is [C6H10O5]n – exactly the

same as for cellulose
However, starch is slightly

soluble in water and cellulose is
not which is a function of the

way the monomers are
connected in the two different
natural polymers
9
to split some of these bonds
One thing that you notice when cleaning up
is that caramel dissolves less in water than
sugar which is what we started out with –
you have to cook the caramel with hot
water in order to dissolve everything, which
is also a consequence of its network-like
micro structure
Most feedstocks in nature (sugar, starch,
cellulose) are made of such networks for a
good reason: plants and animals don’t want
to be dissolved when they get rained on!
Therefore, one of the challenges for us
when using these feedstocks is how to break
the polymers up into monomers that can be
handled easily (like crystal sugar)
Starch, which is typically made from corn,
potatoes, or grains, is another good example
for natural polymers
“natural polymers” consist of many
repeating units (monomers) that have been
linked together
Depending on the chemical composition of
the monomers, natural polymers can be
chains, or networks
A characteristic of starch is that it has a
variety of OH groups on the outside of its
polymeric chains
These OH groups can interact with water
when water and starch are mixed
These interactions are strong and
directional, because the OH group in starch
and water H2O have very similar dipole
moments
HS-PS1-3, HS-ESS2-6,
HS-LS1-6, HS-LS2-4
Biology, High School
1.2 Describe the basic
molecular structures
and primary functions
of the four major
categories of organic
molecules
(carbohydrates, lipids,
proteins, nucleic
acids).
12) Incredible Egg Crystals
Materials: Eggs shells (or eggs,
pushpins, bowl, papertowel), food
coloring, glue, paintbrush, alum
powder (spice section in grocery
store), water, heating plate, glass
that can stand heat (e.g. IKEA),
spoon
http://www.stevespanglerscience.co
m/experiment/incredible-egg-geode
 This strength and directionality leads to the
Other examples for natural
fact that the rearrangement which is
polymers are proteins, DNA,
needed in a normal reacting liquids under
RNA, cellulose (which makes up
pressure is slow
the cell wall of plant cells),
 Therefore, when the pressure is applied very
hemicellulose, lignin
slowly, the starch chains have enough time
to rearrange themselves, but when you
Since starch is made from
apply pressure very quickly, the
plants, it is by definition a
rearrangement cannot proceed fast enough
sustainable material
and the liquid feels like a solid
Waste Prevention
 Alum is a salt of the formula
KAl(SO4)2·12H2O that dissolves well in hot
Nature uses everything that it
water, but not so well in cold water
produces in a waste-free
 Once the water cools down, the solubility of
lifecycle
alum in water decreases, which means that
the anions and cations that are dissolved in
typically, humans and in
water are searching for a place to combine
particular, chemists, don’t work
to form a solid
that way, but produce waste
 Because the egg shell is covered with tiny
instead – may it be municipal
alumn crystals that look like powder to you,
waste or chemical waste, at the
it is much easier for the dissolved cations
basis it is the same problem
and anions to combine with the already
existing solid than to start a new solid
this experiments is trying to
crystal from scratch
show one example of what can  Therefore, most of the dissolved cations and
be done with egg shells instead
anions that want to become a solid do that
of throwing them out – create
transformation on top of the egg shell which
a new step in the lifecycle
is perfectly prepared for them
 Crystal formation and growth is based on
An alternative would be to
the slow and directed formation of a solid
incorporate egg shells in
 Because the water doesn’t get cold at once,
compost that can be used to
but takes some time, the cations and anions
grow plants – plants and small
have some time to establish a very ordered
animals in the earth need the
solid, which you see as crystal
10
HS-PS1-5
HS-PS1-6
Chemistry, High
School
7.1 Describe the
process by which
solutes dissolve in
solvents.
7.3 Identify and
explain the factors
that affect the rate of
dissolving (e.g.,
temperature,
concentration,
surface area,
pressure, mixing).
minerals that are contained in
egg shells (mainly calcium) to
growth and live
 The food coloring you have dissolved in
water becomes incorporated into the
crystals together with some of the water in
solution
 The notation KAl(SO4)2·12H2O means that 12
water molecules are incorporated into a
crystal per Al cation – which are the water
molecules that keep the color in the crystal
For all experiments that are performed indoors, it is recommended to provide an aluminum pan per student or per experiment to simplify
cleanup. All materials used are non-hazardous; thus, waste liquids can be deposited down the drain and solids into regular solid waste. CAREFUL
for experiment 11: all “slime” made from corn starch has to be deposited as SOLID WASTE, as it can clog the drain!!!!!
11