ingridscience

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 has so far been 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.

Before class, find an outdoor route extending in a straight line 63m long, from where the model Sun will be (the exercise ball), to where the model Earth and Moon will be. If a gravel field is used, an orbit path can also be traced on its surface.

In the classroom, show students the Sun (exercise ball), and tell them that if the Sun is this large, Earth is only 5.5 mm wide, and the Moon is only 1.5mm wide!
Distribute the rulers, Earth/Moon images and modelling clay to student pairs. Ask each group to make a model Earth (5.5mm in diameter) and Moon (1.5mm in diameter) from the modelling clay, using the image to guide their colour choice. Students will likely make them too large to start - prompt them to keep removing clay until they are the correct size. Invite students to bring their model Earth and Moon next to the model Sun (exercise ball) to demonstrate how much smaller our Earth is than the Sun. Emphasize that in the classroom, using these model sizes, we cannot place them at the correct distances from each other to show how far apart they are on this scale.
Take the students outside with the model Sun, Earth and Moons, as well as a metre stick/tape measure.
Place the Sun (exercise ball) on the ground, and tell students that, to scale, the Earth and Moon will be 63 metres away from this Sun! Lay down a metre rule/tape measure, so that students can roughly gauge how long their stride needs to be to pace a metre. Then as a class, pace 63m from the Sun. Place one of the Earths at this spot. Look back at the Sun to see how far away it is and how much empty space there is between the Earth and the Sun.
Then place one of the Moons 15cm from the Earth. Indicate how the Moon orbits in a circle around the Earth, one orbit taking one month. At the same time, the Earth is orbiting the Sun, moving on a path always the same distance from the Sun, taking one year to orbit around the Sun..

See this webpage for calculating Sun-Earth-Moon scaled diameters and distances apart: https://www.dunlap.utoronto.ca/~du/solarsystem.html

Optionally, trace out the orbit of the Earth in the gravel (or make a chalk line), walking around the model Sun but always staying 63m (or thereabouts) from it. Tell students that a season passes as the route takes you ¼ of the way around the Sun (then another season if you able to walk ½ way around the Sun). Complete as much of the orbit as possible.
Before heading back to the classroom, use the model to emphasize how far away the Sun and Earth are, and in turn how far the Earth and Moon are from each other, and how much empty space there is in-between.

As an alternative to placing one Earth and Moon, place the Sun, then ask students to pace 63m away, all in different directions, taking their model Earth and Moon. When the students each reach their spot 63m away, tell them to place their Earth. Then place their Moon, 15cm from their Earth. Each of the Earths show a different part of the Earth’s orbit around the Sun. Walk between the student groups, tracing a path if possible, to show the orbit of the Earth around the Sun. Tell students that while the Earth orbits the Sun, the Moon is also orbiting the Earth.