ingridscience

This models how animals combining oxygen (from the air) with sugar (that they eat), to give them energy. The chemical reaction generates carbon dioxide and water. So animals (and plants also), when they respire, put carbon dioxide into the air.

Plants, when they photosynthesize, do the opposite: they take carbon dioxide from the air, and combine it with water to make sugar (which they use to build their structures) and oxygen. Hence, planting trees helps pull carbon from the atmosphere.

Give student groups a set of molecules (one sugar and 6 oxygens).
Ask them to take apart the sugar molecule and combine it with the oxygens to make 6 water molecules (tell them H2O) and 6 identical other molecules.
Students will eventually arrive at carbon dioxide as the second product molecule.

All living things do the same thing - they use food energy (sugar molecules) and oxygen to make energy, and put carbon dioxide into the atmosphere.

Plants, as well as respiring like animals, also do photosynthesis. This is the opposite chemistry.
Demonstrate (or students can build) 6 carbon dioxide and 6 water molecules combining together to make the reverse chemical reaction, producing a sugar molecule (glucose, C6H12O6) and 6 oxygen molecules.

The carbon dioxide in the air dissolves in the ocean, and becomes part of the shells of ocean animals and is also made into rock.
This activity shows the chemistry of how that happens.

First model the chemical reaction with molecule models, if available:
Ask students to combine their carbon dioxide molecule and their water molecule to make one molecule. Tell them that there are several possibilities, but the molecule that forms in the ocean has a double bond and is symmetrical. They should eventually arrive at H2CO3 (carbonic acid).
In the ocean, this molecule loses its H atoms to make carbonate, which animals use to make their shells.
(Some rocks are also made by this same chemical reaction.)

Show students an oyster shell, or other white shell. This shell is made from calcium carbonate.

Tell students they will do some chemistry to make their own shell material.
Ask students to place their clear dish on top of the black paper, then squeeze a little 'carbonate' and a little 'calcium' into the dish - a white precipitate forms.
They made a new chemical, calcium carbonate. A chemical reaction happened.
Animals in the ocean do the same chemical reaction to form their shells from ocean molecules.

If sand gets on the magnet, it is hard to remove, so:
either put a magnet in a baggie, then move it over a pile of sand,
or put some sand in a baggie, then move the magnet over it.

The magnetite grains in the sand will be strongly attracted to the magnet.
Using the magnet, the dark grey magnetite grains can be separated from the rest of the rock types in the sand.

Magnetite is a mineral containing iron.
It is the most magnetic of all naturally occuring minerals on Earth.
Small grains of magnetite are very common in igneous and metamorphic rocks.

Discussion on magneto reception in animals:
Bees, as well as bacteria and many migrating animals like birds and turtles can sense the Earth’s magnetic field and the patterns it makes. They use it to migrate with the seasons, and to map and find their breeding and feeding grounds.

Bird migration map:
Bird migration: https://www.allaboutbirds.org/news/mesmerizing-migration-watch-118-bird…

We don’t know exactly how magneto reception works - we are still researching how.
One theory is that the tiny magnetite particles found in some animals (in bird beaks and fish noses) are attracted to the magnetic field of the Earth. The magnetite signals which way is North, and is also sensitive to the variation in magnetic field strength in different places across the Earth.
Another theory involves a protein in the retina of animals' eyes.

Magneto reception is found in these animals:
arthropods incl. insects - honey bee, fruit fly, ants
molluscs - sea slug
fish - salmon
amphibians - salamander, newt
reptiles - turtles
birds - canada geese etc etc
mammals - brown bat
humans - we don’t know of a behavioural change, but an affect on our alpha brain waves has been found

Students look and carefully handle the skulls.
Ask them which is from a predator animal and which a prey, by looking at the positon of the eye sockets and the shape of the teeth.

Prey animals have their eyes on the sides of their head, so they can see all around them and spot approaching predators. Their teeth are wide and flat, for grinding plants.
Predator animals have their eyes in the front of their head, allowing them to see in stereo and so accurately gauging the distance away of animal to chase. Predator teeth are sharp, to rip flesh.

Lay out the skeletons and skeleton images.
I use a deer skeleton just assembled by the class, a snake skeleton (in a display case), mouse skeleton (a jumble of bones in a magnifier box, and one femur leg bone in its own box).
Ask students to find the same bone in the different animals.

Add 4 or 5 bean seeds to a tub of water overnight or for a couple of days, until the seed coats start to split.
The seeds can be planted directly in the soil at this point, or for faster visible results in the jar, sprout the seeds before planting: Layer the seeds between lightly-dampened paper towels and seal in a baggie to keep the moisture in. Sit in a dark place (e.g. wrapped in a dark tea towel) for up to four days, until a root has started to emerge.

Add the potting soil/sand mixture to the mason jar and stir in a little water to make moist but not soggy.
Make four or five dents in the soil and carefully lay the sprouted bean seeds in them (do not break the root tip).

Optionally, have students breathe some carbon dioxide (in their exhaled breath) into the jar, for reinforcement that the plants will need the CO2 contained in the jar.
Seal the mason jar and place in a light, but not hot, place in the classroom.
Within a week, leaves will start to emerge. Speed of growth depends on the temperature of the classroom.

Once visible growth has happened in the jar, the beans can be planted in a garden. Usually about a week.
The contents of the sealed jar will become stinky, and the beans will start to rot, if left for too long. (This happened after two weeks for us.)

Discussion:
The seeds grow into a plant, using only the air and water in the jar, and the energy of the sunlight that hits the jar.
Plants build their structure from CO2 and water. (They also respire, using oxygen in the jar.)
Plants remove carbon dioxide from the air, hence today's focus on reforestation and tree planting.

Students find leaves, rocks and other natural/manmade items from the school grounds.
Use a flat area or picnic tables for students to arrange their items into repeating patterns.

Students in small groups use sidewalk chalk to create a number pattern.
The rest of the class guesses the next numbers in the pattern.