ingridscience

Add hot water to one container, and cold water to another. Allow to sit for 30 seconds so that the water is not sloshing in the container.
Drip one drop of yellow food dye at one side of each container, and one drop of blue food colouring to the other side of each. (Alternatively, just a drop of blue in each.)
Watch how the food colouring mixes through each.
The blue and yellow will mix much faster to make a green colour in the glass of hot water. (With blue alone it will mix into the warmer water faster.) This is because the hot water has currents in it (as water evaporates from the surface). The food dye molecules get carried along by these currents.
The colder water has slower currents, so the food dye does not mix into the water as quickly.

Note that this is not diffusion, but showing the water currents in hot and cold water.

Note this activity is not chemically accurate, but is a much simplified version of the chemical changes.

Start with the N2 molecule.
Then give students the atoms needed to move around the cycle.
Give them clues each step to aid in model building: they might need to make two identical molecules, or that they should make a water molecule first, then use the remaining atoms and bonds to make the other molecules.

At each step, explain how living things make and use the molecules:
Plants need nitrogen but are not able to use the nitrogen in the air. They rely on bacteria to catch it.
Bacteria in the soil, and some specialized bacteria that live in the roots of some plants can “fix” the N2 to make NH3 (and also NH4), which can be taken up by plants.
In the soil extra ammonia is converted to another molecule, nitrate, by bacteria when there is oxygen around.
Nitrate is converted to nitrogen gas again, by bacteria. More H is used.

For the ammonification process, see salmon decomposition activity.

Walk to collect soil from various sites around the school/neighbouring park. Add collection sites to a map.
Take soil from 10cm below surface to make sure the chemistry of the actual soil is measured.

Mix 1 part soil with 5 parts water. We added 5ml soil to a tube, then water to 30ml. Shake 1min, then settle 10 mins (allow to settle on walk back).

In class, filter the soil, by carefully pouring the water that is above the settled sediment through a coffee filter paper into a new tube.
Some soil samples will now be clear, some will not. Run again until they are as clear as they can be (so that colour tests are easier to see).

pH test
The first chemical test of our soil samples is for pH, which measures how acid something is. Soil does not get extremely acid, or extremely basic in the other direction, but it will vary enough to affect what can live in it.

Our instructions for testing: Add pH powder from capsule. Add 4ml of the liquid to tube. Shake 1 min. Record pH.
See the map image for the soil pH readings we got from around a school and neighbouring park.

Discussion of pH results:
What might affect how acidic or alkaline soil is?
Rainfall: Acid soils are most often found in areas of high rainfall. Excess rainfall leaches base (the opposite of an acid) from the soil. Additionally, rainwater has a slightly acidic pH of 5.7 due to a reaction with carbon dioxide in the atmosphere that forms carbonic acid.
Weathering of minerals: rocks are broken up and washed into the soil, and affect its pH.
Plant root activity: plants release H+ ions from the root.
Acid rain: When atmospheric water reacts with sulfur and nitrogen compounds that result from industrial processes, the result can be the formation of sulfuric and nitric acid in rainwater. The amount of acidity that is deposited in rainwater is much less, on average, than that created through agricultural activities.
Fertilizer use: Ammonium (NH4+) fertilizers react in the soil in a process called nitrification to form nitrate (NO3−), and in the process release H+ ions.

Different plants are adapted for different amounts of acidity. Bogs are usually more acidic.
Potting soils are manufactured to be neutral so that a wider range of plants can grow in it.

NPK tests (nitrogen, phosphorus, potassium)
Instructions with our soil test kit: Add N/P/K test powder from capsule. Add 4ml soil liquid. Shake 1 min. Allow colour to develop - about 10 mins.

While the colour is developing, look at the chemistry of one of these in the environment: nitrogen - do the "molecular modelling of the nitrogen cycle" activity.

Look at our tests
Our nitrogen results (pink) were very low - what does that mean? Not much nitrates. The nitrogen might be in other forms: nitrite or sequestered in the plants and animals.
(One of the potting soil tubs had higher nitrogen).
Nitrogen is needed for proteins, and chlorophyll, which makes the leaves green.
If plants turn yellow, they may need fertilizer.

Phosphorus was very low in woods, higher in one potting soil. Phosphorus has a whole other cycle. Needed in plants for photosynthesis.
We need it to make ATP, which carries energy.
In whole grains and nuts.

Potassium was higher everywhere. Whole other cycle. Needed in plants for photosynthesis; proteins.
We need it for our nerves to fire.
In potatoes, tomatoes.

Many other minerals needed by plants.
We eat the plants and get them too.

Submerge an uncooked egg in vinegar, and place in a safe place on a counter or shelf.
Wait a few days to a week.
Look at periodically to follow the changes.

The shell will bubble as the vinegar reacts with the calcium carbonate in the shell, releasing carbon dioxide gas:
CaCO3 (calcium carbonate of the shell) + 2 CH3COOH (acetic acid of vinegar) -> Ca(CH3COO)2 + H2O (water) + CO2 (carbon dioxide gas)

The hard shell reacts away completely, leaving the egg surrounded just by the membranes. The egg is soft, but still intact.
The membranes prevent bacteria from reaching a developing chick inside the egg, and stop moisture from leaving too fast and allow air and other gases to pass.

Students build a wooden project.
We built a perch for chickens.
As the pieces of wood are cut and attached together, discuss how each tool is a simple machine, and how it makes the job possible.

Saw is a wedge.
Hammer is a lever.
Nails are wedges.
Screw is an inclined plane.
Screw driver is a wheel and axle.

Introduction:
On the BC coast, we hear a lot about oil pipelines and oil tankers. With increased oil tanker traffic in our bays and ocean there is an increased risk of oil spills.
The first activity will look at the effect of an oil spill, and how we attempt to clean it up.

I will give you oil to spill in your ocean. (Show students the simulated oil: cocoa powder mixed into the vegetable oil in the jar.)
Then you will use the materials to clean up as well as we can:
String models the booms that are dragged across the water to stop the oil from spreading and bring it together. Hard if there is wind on water.
Cotton balls are the skimmers that stick the oil to them and pull it out of the water.
Last step, which we will do when you have cleaned up as much as you can, is to add a dispersant (detergent).

Add oil to your ocean.
Your model is 100 billion (11 zeros) times smaller than the oil that was leaked into the Gulf of Mexico. (210 million US gal)
What is happening to the oil? It spreads out. The Gulf of Mexico spill (started in 2010) was a trillion (12 zeros) times larger area than your model. It is restricted in your container - but of course is not in the ocean so spreads further. See the Gulf oil spill at https://en.wikipedia.org/wiki/Deepwater_Horizon_oil_spill#/media/File:D…
Notice that some of your oil sinks - bitumen behaves like this, making it almost impossible to clean up.

Now try clean up:
Loop the string around a patch of oil, to model how booms are spread around an oil spill. Try and contain the oil and pull it to one side of the container. It is somewhat effective, as are booms for real oil spills. Boom image link: https://en.wikipedia.org/wiki/Boom_(containment)#/media/File:Oil_Spill_…
The diesel spill in Bella Bella, BC was hard to contain as the weather was bad. Bella Bella image link: http://i.huffpost.com/gen/4799172/thumbs/o-BELLA-BELLA-OIL-SPILL-570.jp…
Then use the cotton balls to try and soak up the oil. For real oil spills skimmers are used, which similarly soak up oil into absorbent pads. How effective is this in your model? It is hard to be fully effective for a real oil spill. Skimmer image link: https://en.wikipedia.org/wiki/Oil_skimmer#/media/File:Drumskimmer_004.j…
The last step is to add dispersant (or a detergent) to break up the oil droplets and disperse them. Add diluted dish soap to the remaining oil, to observe how it breaks the oil into smaller droplets. 2 million gallons of dispersant were used in the Gulf. Dispersant application image link: https://upload.wikimedia.org/wikipedia/commons/6/61/C-130_support_oil_s… Dispersants break up the oil, but it does not go away. Dispersants themselves are also harmful to wildlife.

Spilled oil can harm living things in several ways. Oil is a poisonous chemical which animals can be exposed to internally through ingestion or inhalation, or externally on skin and in eyes, causing organ damage and cancer. When oil coats feathers and fur it destroys their ability to keep animals warm. Dispersants reduce the impact of oil on shoreline habitats, but disperse oil into deeper ocean water where it has harmful effects on deep ocean wildlife.

The sponge, corn kernels and corn meal model different kinds of food of different sizes (different sized foam pieces are also pictured). The utensils represent different kinds of ways that fish catch food.
What is the easiest “food” to catch with each kind of mouth?
Students can use the worksheet to record what they find.

Results and discussion:
Some fish feed by biting pieces off their prey e.g. sharks, piranha, adult salmon. The tongs and clothes pegs grabbing onto large pieces of foam model this kind of feeding behaviour.

Fish use suction feeding. Food that is smaller than the mouth is sucked into it by a pressure difference when the mouth is opened. Most bony fish feed in this way. The baster or pipette sucking up medium and small pieces of food models this kind of feeding behaviour.
For a video of suction feeding try Wikipedia webpage “Aquatic feeding mechanisms”: https://en.wikipedia.org/wiki/Aquatic_feeding_mechanisms.

Some animals, instead of sucking water (and prey) into their mouths, move forward to engulf prey their mouths - called ram feeding.
The prey is trapped in the gill raker (a mesh). Tuna and whale shark eat this way.
Baleen whales use a specialized form of ram feeding called lunge feeding. They move forward fast to take a huge gulp of water and food, then expel the water through their baleen, which trap the krill in its mesh. Humpback whales lunge feeding video - try this link: https://www.youtube.com/watch?v=euYTbsjTJyo
Ram feeding modelled by the slotted spoon or spatula.

When tiny animals are caught by a mesh or filter, it is called filter feeding. Water and food can be brought into the mouth by either suction or ram feeding, then the water is expelled.
Baleen whales technically filter feed, as do fish with specialized gill rakers that catch tiny particles (e.g. some sharks and herring).
Barnacles, mussels, oysters and other shelled animals catch tiny animals from seawater in their filters.
Filter feeding of tiny particles is modelled by the tea strainer and sieve.
Watch real barnacles feeding as an example of filter feeding.

Discussion related to salmon:
Young Atlantic salmon (alevins) start feeding using the ram feeding method, moving their body forwards to capture small animals. After a week or so of feeding that way, they switch to suction feeding, to pull prey into their mouth from a distance. https://www.nrcresearchpress.com/doi/abs/10.1139/f91-225#.XK-IgC3MzdQ
Adult salmon use their teeth for eating (though sockeye don't have big teeth and continue to eat krill).

See animal eating methods for a similar activity.