The Fairy-Land of Science · Lecture X, part 2 · Part 10: Lecture X: Bees and flowers
28. Flowers with clever tricks
Goal: Your child can show how a flower's shape makes a bee pick up pollen, using a pencil in a sage or salvia flower (or a similar flower).
You'll need
- A flowering sage or salvia plant (garden centers sell many kinds), or dead-nettle, nasturtium or wild geranium
- A sharp pencil
- A magnifying glass
- Science notebook and pencils
What's in the book
Pages 219 to 225. Bell-shaped flowers hang down to keep rain out of their honey; hairs and sticky stems keep ants away; Sprengel discovers why flowers have honey, from the wood geranium; the geranium's stamens stand up five at a time; the nasturtium's long spur; the dead-nettle's hood and lip; and the salvia's swinging stamens that tap pollen onto a bee's back.
The lesson, step by step
Hook question
SayAn ant likes honey too. Why don't flowers want ants?
Read or tell page 219: an ant is so small it creeps past the pollen without carrying any.
Look for example at the hairy stalk of the primrose flower; those little hairs are like a forest to a tiny ant
Read together
Read page 220 about Sprengel, a young German botanist who wondered what some little hairs in a geranium were for, and found they kept rain off the honey.
the purple lines which ornament it all point directly to the place where the honey lies
SayThe lines on many flowers are like arrows saying "honey this way."
The geranium and the nasturtium
Look at Fig. 58 on page 221. The geranium's stamens stand up five at a time to dust the bee, and only when all the pollen is gone does the sticky center open. So it must get pollen from another flower.
The nasturtium hides its honey at the end of a long spur. If you have one, find the spur with your finger.
Try it: the salvia trick
Read pages 224 and 225 and look at Fig. 60.
You can easily try this by thrusting a pencil into any Salvia flower, and you will see the anther fall.
Gently push the pencil point into the mouth of a sage or salvia flower, the way a bee pushes in her head. Watch the stamens swing down onto the pencil. Pull it out and look for pollen on the pencil with the magnifying glass.
The dead-nettle
Read or tell pages 222 to 224. The dead-nettle's flower has a wide lip for the bee to land on and a hood over the top with the pollen bags tucked inside. As the bee pushes in for honey, her back touches first the sticky stigma, then the pollen.
Purple dead-nettle and henbit grow as common weeds in many American yards in spring. Dead-nettles don't sting, but check with an adult before picking any plant.
Tell it back and check
Your child tells back how the salvia dusts a bee. Then ask:
1. Why do bell-shaped flowers hang down?
2. What are the lines on a petal for?
3. Why is it good for flowers that a bee keeps to one kind of flower?
Draw it
Draw a bee pushing into a salvia flower, with the stamens swinging down onto her back.
Afterwards
Notice it this week: look for lines on petals that point inward, flowers hanging their heads, and hairy flower stalks.
Tip
Garden sage, salvias and many flowers in the mint family work for the pencil trick. Try young, fresh flowers; older ones may have lost their pollen already.
Answers to the book's problems
1. To keep rain and dew out of the honey. 2. They point the bee to the honey. 3. The pollen she carries is of use only to the same kind of flower, so it isn't wasted.
Worked out for this site from the scan. If a number in your copy differs, trust the book.