Smell molecules posting game
Spread pots around the site, each displaying a smelly molecule image. They should be placed near the plant that releases their smell molecule, or bring in plants to place next to each pot. I used these smell molecules and plants (molecules pictured in attached file "table of smell molecules and plants for posting game"):
A sprig of rosemary next to a pot displaying the eucalyptol molecule.
A sprig of lavender next to a pot displaying the linalool molecule.
A sprig of lilac (or any sweet-smelling flower such as rose or geranium) next to a pot displaying the geraniol molecule.
An apple (or banana or other ripe fruit) next to a pot displaying the isoamyl acetate molecule.
Next to some grass (or any green leaves that release the mown-grass smell), place the pot displaying the hexenal molecule.
Next to a cedar (or other evergreen tree), place the pot displaying the pinene molecule.
Shuffle the molecule cards, then give one to each student, but ask them to wait until everyone has a card before starting. Instruct them to post their card into the pot with the same molecule on the top. Some of the molecules look similar, so they should check the match carefully. Ask them to also smell the plant next to the pot to see what the molecule smells like.
The students can start out all at once. As they each return from posting their molecule card, give them another card to post. Keep distributing the cards, one by one to the students that return, until all the cards are posted. (Or end earlier if needed.)
Bring all the pots back to the group, and ask students which molecules looked similar to them (e.g. eucalyptus and pinene, or linalool and geraniol). Although they look similar they have different smells. Our nose can distinguish between the smells by this mechanism: each smell molecule fits into a different molecule in our nose. Once the smell and receptor molecule dock with each other, they trigger a neuron to fire which sends a signal to our brains to sense a smell. (Actually it is a little more complicated as smells are usually made up of more than one smell molecule, and the combination of receptor molecules that are triggered induces the distinct smell sensation in our brain.)
Discussion on how plant smells are used to communicate with animals:
Sweet smells are given off by flowers to attract pollinators to them.
Smells like eucalyptus and pinene repel insects, to discourage insects from eating the plants that release them.
The ripe fruit smell (isoamyl acetate molecule) attracts animals to eat the fruit (and hence distribute the seeds in them).
The grass smell (hexenal) is made when green plants are crushed or damaged. It is thought to induce defence responses in neighbouring plants so that insect damage to them is limited.
Pollinators posting game
Short discussion/review on why flowers are different colours, smells and shapes - to attract different pollinators. The pollinators collect nectar and/or pollen from flowers for themselves. At the same time they brush against pollen and move it from one flower to another, so fertilizing the eggs, and making seeds.
Bees, butterflies, humming birds, moths, flies, beetles and bats all pollinate flowers. Some flowers are pollinated by only one kind of pollinator, and some are pollinated by many kinds. (Wind is also used by many plants to simply blow the pollen between them.)
Place pollinator pots, each containing an image of a pollinator, next to a flower that the animal would visit (or bring in flowers to place next to the pots):
Bee - attracted to bright coloured flowers with a sweet smell. The flower can be any shape, including tubular as long as the bee can fit into it. (They also use nectar guides: visible or UV patterns that guide the insect to the nectar.) I used a bluebell.
Butterfly - attracted to bright coloured flower with an odour. The flowers are often wide, so the butterfly can land on it, but the butterfly can also fit its proboscis into a tubular flower. Butterflies use patterns or nectar guides to find the pollen. I used a marigold.
Fly - attracted to white/green/yellow/brown coloured flowers, often with funky/putrid odour (not sweet). Flies have a short tongue, so need a bowl-shaped flower. I used a buttercup (bees and beetles also pollinate buttercups).
Humming bird - red/yellow/orange coloured, odourless, tubes/funnels/cups. I used honeysuckle.
Beetle - white or green coloured, odour can be absent or strongly fruity, large bowl shape to crawl into. I used a dogwood flower.
Moth - dull red/purple/pink/white coloured, strong sweet smell emitted at night, various shapes.
Give students one square with a pollinator image on it. Ask them to post it in the correct tub, before coming back for another one.
Students keep posting until the picture squares run out.