Chris Fautley joins pupils on an outing to Wisley garden
"Science is nothing but trained and organised common sense," wrote Thomas Huxley. Maybe, but key stage 3 students from Tomlinscote School in Frimley, and Ash Technology College (both in Surrey) found it is also fun when they were invited to the Royal Horticultural Society's Wisley garden to celebrate Science Week.
On the programme: the Beetle Bug Ball; a muddy session with Dr Dirt; and how to extract DNA from a strawberry - all supported by stag beetle pupae, an umbrella plant, and a lump of clay. Let's hear it, too, for the show's stars, the RHS plant scientists - their mission: to demystify the world of plant science.
The day comprised a series of half-hour activities with scientists pedalling their knowledge to small groups of students. Soil scientist Paul Alexander brought along trays of sand and clay, allowing pupils to test their properties: knead it, roll it, stretch it, soak it... all in the name of establishing soil type.
Meanwhile, Drs Tijana Blanusa and Ian Waghorn are demystifying the worlds of photosynthesis and chromatography. Why are leaves green? Because they contain chlorophyll that enables plants to photosynthesise. Cue an experiment with spinach juice to see how much chlorophyll it contains.
Juice is dripped onto cellulose paper and dried with a hair drier to make the chlorophyll bind and stick. The paper is dipped into petroleum ether, causing colour in the dried juice to run so that results may be compared with a colour chart. Orange means carotene is present; light green - xanthophyll; mid-green - chlorophyll A; dark green - chloropyhll B. There is also the chance to try a nifty device that takes instant chlorophyll readings from leaves; thus, a sickly umbrella plant's yellow leaves return a very low reading.
"When you see almost any insect under a microscope, it is an object of architectural beauty." It's the Beetle Bug Ball slide show, where topics discussed include how forensic entomologists ascertain time of death by examining the insects present on a body, and how insects help clear up after us.
What does DNA look like? Plant pathologist Caroline Gorton helped us find out. Everybody is presented with a tube of strawberry puree. What follows reads like a recipe. Filter; transfer to a test tube; add detergent and salt solution; add ethanol. As DNA is not soluble in ethanol, it should rise to the top of the mixture. Sure enough, it does.
Millie Parsons, a science teacher at Tomlinscote School, said the DNA session would be a good grounding for KS4. The subject of plant adaptation had been enlivened simply by having experts who were able to talk about it.
"That was useful, and not something we would do in school. It will broaden their knowledge about what plants need," she said.
lSchools facilities at Wisley focus on KS12, it can also offer guidance with KS34.
SOIL TEXTURE TESTS
Take a golf ball-sized lump of soil. Knead in one hand, add water until it has the consistency of putty. Ensure any lumps are disintegrated.
Will soil form a ball? No.
Can soil be rolled into a ribbon? No.
Loamy sand? Yes.
How long is ribbon?
4a. Less than 2.5cm, smooth and slippery... silt loam.
gritty... sandy loam.
neither smooth nor gritty... loam.
4b. 2.5cm-5cm, smooth and slippery... silty clay loam.
gritty... sandy clay loam.
neither... clay loam.
4c. More than 5cm, smooth and slippery... silty clay.
gritty... sandy clay.