Authors: Meredith Thomsen and Brian Kraatz
Overview: In this lesson, students learn how scientists preserve plants for museum collections, and do the first steps of making their own plant collection.
Collecting and preserving organisms is part of the observing that natural scientists do. Information collected with the organism is just as important as sample itself.
(Students also start learning skills of pressing and mounting plants.)
Example herbarium sheets
Student plant presses (We gave them out with cardboard and paper already inside, but sheets weren’t alternating yet. Also used rubber bands and had no problems with them.)
One pair of clippers/teacher.
Advance preparation: Assemble plant presses.
Time: 45 minutes
Grouping: Whole class for intro, then 6-7 students/leader, then whole class.
Teaching tips: Keeping students in small groups for all the outside part (as written) would work better than how we did it! Use that UGSF …
How you introduce activity will depend on what you’ve done so far. One possibility:
Our program focuses on “California Biodiversity”, “the many kinds of life in California”
During last 2 weeks of class they’ve started learning some of the skills you need to become scientists who study the many kinds of life in CA (solicited from students): Observing, Questioning and Testing
For scientists who study the natural world, a big part of the observing they do includes collecting and preserving samples of the living things they see (what this means). We’ll talk a lot more later this year about what scientists do with these collections … right now we’re going to focus on the skills you need to collect organisms, starting with plants.
Show students finished herbarium sheets, one per/student if possible (warn them to treat specimens respectfully). Note that as many plant parts are shown as possible, backs of leaves, etc. (Can have students raise hands if they’ve got stems, leaves, flowers, buds, fruits, seeds, etc.) Mention that plants preserved this way can last hundreds of years. Point out collection information on label. Collect herbarium sheets.
Hand out plant presses; tell students these are tools called plant presses, used by scientists to preserve plants like the ones you just looked at. Come in many sizes. These are yours to keep and use for class and field trip activities. Have students write names on presses, then open them up and reassemble with alternating paper and cardboard (“paper sandwich!”). Explain parts and how we’ll use it.
Instruct students to take their field notebook, press, and a pen; leave everything else. Assign students to groups headed by a teacher (GSF or UGSF). That person leads their group to area where plants are collected and (quickly as possible) clips a piece of whatever plant each student selects.
Get to a place where it’s easy for students to sit and write (separate from other groups), and have them do a field notebook entry on collection area, plus a written/drawn description of their plant. Prompt them to include what plant parts they have collected (stem, leaves, petals, etc.), detail about texture, color, whatever. Include information about plant like growth form, height, etc.
Then have students open their presses, and help them press their plant. Remind them to show both sides of leaves, etc. Can bend stems around if too big for press.
Close presses, get everything together, go back inside; aim to have students in desks within 5 minutes of end of class. Collect presses and notebooks.
Wrap up: Today you started learning a skill you’ll use in the field to collect and preserve plants, which is part of the observation you will do as scientists studying California biodiversity. Next week we will teach you how to mount them, and make some more observations on the species you collected.