Archive for September, 2013

Autumnwatch #4: The Comma: Is it a leaf? Is it a form of punctuation? No, it’s a Butterfly!

IMG_0465  Another butterfly that you might catch flying on these sunny Autumn days is the Comma (Polygonia c-album). A member of Nymphalidae, it is drawn to late autumn flowers and fallen fruit. It’s a very interesting species for a number of reasons. Firstly, look at that camouflage! The whole wing shape of the Comma has evolved to look like the shape of a dead leaf; when it closes its wings, all you see are the crinkled brown undersides, a perfect illusion. Even the attractive uppersides are an aesthetically seasonal mix of orange and brown.IMG_0407

GRAMMATICAL BUTTERFLIES?

So why the unusual name? Well, if you look closely in the picture below, you can see a little white mark on the underside of the wings that looks like… a comma. Bizarrely enough, the butterfly has a North American relative called ‘The Question Mark’ that has a white mark that looks a bit like…a question mark! (I challenge you to a cross-curricular link to this preparation for Mr Gove’s SPAG test!)

IMG_0417

Spot the comma…

question-mark-butterfly-with-folded-wings-doris-potter

And spot the question mark on its North American friend..
(Picture source: Fine Art America)

FLUCTUATING POPULATIONS

The Comma is now quite a frequent sight across Britain, but once the situation was very different. At the turn of the century, numbers started a massive decline; by the 1920s there were only a few colonies left in Hereford and Worcestershire. Happily, things suddenly and inexplicably improved, and this species is one of the few butterfly success stories of recent years.

More info and photos here…http://www.ukbutterflies.co.uk/species.php?species=c-album

Advertisements

AUTUMNWATCH #3: MAPLE OR SYCAMORE?

IMG_0677So then, on to identification of some common leaves… Today we’re tackling some species that belong in the same genus and are often confused: the Norway Maple and the sycamore.

In fact, our heading is really a trick question; these are both technically Maples, sharing the genus Acer. They are also relatively common, frequently planted in school grounds, and you are likely to come across them during your Autumn leaf searches.

IMG_0675

Norway Maple

The picture above shows a Norway Maple leaf on the left and a Sycamore leaf on the right. The main difference is that the Norway Maple has a significantly more jagged edge, and a glossier surface. In fact, although not the same species, it looks very similar to the Maple leaf on the Canadian flag. In looking at the full trees, Sycamores also tend to grow higher.

In Autumn, the leaves become much easier to tell apart. Norway Maple leaves are some of the first to change  colour, turning a blazing scarlet that illuminates streets, parks and woodlands. There’s a dark side to this beauty; actuall,y this red pigment is produced as a side-effect of something called allelopathy. This is the scientific name for a sneaky trick the tree has up its sleeve to fend off competition for resources from nearby trees. Norway maples produce and release chemicals to hinder the growth of nearby saplings. The blood-red pigments are merely a by-product of this.

Sycamore leaves never turn red. They usually go a blotchy green-yellow. This sample is also adorned with black spots; rather than a consequence of autrumn colour changes, this is actually a fungus that becomes an increasingly common sight. Although it doesn’t look so nice, and the trees probably aren’t too happy about it, spotting this is actually a positive sign. The fungus can only flourish in very clean air, so it’s a great environmental indicator for air quality.

IMG_0676

Sycamore

(OPAL have some tree health surveys based around this that you can do in your school grounds).

So, in summary; sycamores grow taller, and their leaves turn yellow. Norway maples turn red, are a bit selfish, and have glossier leaves. Both trees share the ‘helicopter’ keys beloved by children and so useful when teaching seed dispersal, so it;s worth getting to know their names.

Before we go, there’s one more maple tree to be mentioned: the Field Maple is smaller and less showy than both of the others. Sometimes it is used as a hedging plant. It’s leaves are smaller and more rounded, and turn yellow rather than red. It too produces ‘helicopter’ keys, but they are much smaller.

Fieldmaple_leavesDC250

Field Maple

Autumnwatch # 2: Falling leaves

800PX-~1

The Autumn colours are starting to appear, and autumn activities are starting to appear in school. Artwork, songs, poems and the like can all benefit from a little bit of subject knowledge. We’ve mentioned the new curriculum’s focus on plant identification before , and the preponderance of leaves in autumn activities provides a great opportunity for embedding some of this. Sending them on a hunt for colourful leaves, for instance? Well, why not give them a leaf ID sheet to throw in some science to the mix. In our Autumnwatch posts we’ll help you identify some of the most colourful, popular and frequently seen leaves, and provide some info and trivia about them. First of all, though, a bit of background to the science behind Autumn leaves…

WHY DO LEAVES FALL?

Leaf fall, or to use its scientific name, abscission, is a result of several factors. Mainly, this is due to trees cutting their losses as winter approaches; it takes a lot of energy to maintain leaf production, especially in the face of cold weather and long dark nights. There is relatively little time for photosynthesis anyway at this time of year, so basically deciduous trees just give up. (Wind and insect predation are also contributing factors).

WHY THE COLOUR CHANGE?

Leaves are green because of chlorophyll, the pigment used in photosynthesis. There are also yellow xanthophyll pigments and orange beta-carotene in the leaves, but these are masked by the bright green colour. When photosynthesis stops and leaves die off, there’s no need for the chlorophyll either, and it degrades into colourless chemicals. Now, the yellows and oranges are revealed in all their glory. Red colours are a little different; these are actually synthesised as new pigments once about half the chlorophyll has degraded.

Brown colours are not pigments, but the dead cell walls of the leaves.

The colours vary depending on different trees and their different pigments. More info on the different trees and their leaves as Autumnwatch continues…

“How do you sink an orange?”, and other floating and sinking conundrums…

If you follow us on Twitter, you may have been racking your brains over our recent science pub quiz question, “How do you sink an orange?” Read on…

FloatingOrangeStep2

FLOATING AND SINKING

‘Floating and Sinking’; that well-known chestnut of primary science experimentation. I suspect this is one experiment that many teachers dread, for fear of flooded classrooms, sodden literacy books and angry parents demanding to know why little Tarquin has come home with a soggy jumper. To be fair, this is wholly understandable- it takes more than a faint heart to give 30+ children carte blanche with tanks full of water!

However, it really is worth avoiding the concomitant temptation to make floating and sinking experiments entirely teacher-led. In my experience, trusting the children (and telling them that you are trusting them), along with clear ground rules, really do pay off, and if you make the experiment interesting and pacy enough, most children shouldn’t need to resort to splashing.

EQUIPMENT TO USE

if you can find one, a fishtank is good to use at the front of the class, for ease of viewing through the clear sides (chat to the caretaker, most schools seem to have the relics of a failed aquarium somewhere). However, the disadvantage is that they are very heavy and awkward to move when full of water. A cheaper, easier and still effective container is a basic clear plastic box, the kind that staffrooms/store cupboards are full of. (I temporarily emptied out some Spanish resources to pinch the boxes for an afternoon). It’s good to get as many as you can of these, my personal preference is to have 4 or 5 groups with a ‘tank’ each. This means they can all see, all get chance to have a go, and hopefully stay more engaged.

If you’re really not sure about having several tables running the experiment at once, this could be a one-group-at-a-time activity . Many KS1 classrooms have a water tray, KS2 classrooms could even try to pinch one of these for a lesson.

When it comes to choosing objects for conducting the experiment with, it’s good to try and deviate from the obvious examples. Yes, you want some easily predictable ones in there, but try and maintain interest (and stretch the more able), by bringing in some more unexpected objects, that might not react as they expect… you could even pick a silly object like a pineapple, a toy or somesuch – maybe not the most scientific on the surface, but it keeps the experiment fun, keeps the kids talking and you’d be surprised how these things can actually spark off scientific conversations

Try..

1) A paper clip

2) a heavy rubber ball, about the size of an orange.

3) an orange

4) a biro

The ball and the orange are an interesting pair. If you pick a dense enough ball, it should sink, while the orange will float. This is due to the orange’s air-filled, pitted skin, but it’s good not to explain this; If anything, leave it open for talk partner time, or a possible extension to the investigation…

EXTENDING THE INVESTIGATION 1 – PLASTICINE BOATS

Plasticine is a great material to use for floating and sinking, and to introduce surface area/density. A small, dense ball of plasticine sinks, but a boat or raft shape will float; as an extension, let the kids investigate the different shapes – what will they have to do to make it float? Why does it work?

EXTENDING THE INVESTIGATION 2  – SINKING AN ORANGE

So, we’re left with our orange conundrum. Next, take a single segment of orange and ask the children if they think it will float or sink. As it is smaller, and part of the same fruit, most will predict that it too will float. Drop it in, and watch the perplexed faces as it sinks! Get the children talking about what the differences might be, and why a smaller object sinks when the bigger one floats. A next step is to give the children an orange in each tank and ask them to make it sink. They will see that even holding it under water doesn’t make it sink for long, as each time it bobs back up. They should hit on the idea of peeling it and segmenting it. Can they work out what the most important thing they did was? You could demonstrate how the peel works by putting a ball in a rubber ring – it’s essentially the same effect.

As a further extension, you could even give each group a whole, peeled orange and see if they can get it to float again. we did this immediately after the plasticine boats experiment at a science club, and it was really interesting to see them synthesise their knowledge. Some children tried to place it on a boat or raft, some tried to spread the surface area by segmenting it and then placing it on a raft, while others tried to make a plasticine ‘peel’ for the orange. All of the ideas were valid, even if they didn’t work, and all the kids were having great’ science talk’, a key facet of the new curriculum.

SUMMING UP

So, in conclusion, I guess my main point here is “don’t be afraid to experiment and risk a few splashes”! Deviating slightly from the standard, safe options into more child-led learning will give some great results. Now, which other fruits can I try to sink? Next on the list is a kumquat…

Autumnwatch – resource alert!

IMG_0466

I think i jinxed things when I said that it isn’t really Autumn yet… it certainly feels like it. Well, as you wrap yourself up in scarves, prepare your conkers for battle and await our next full Autumnwatch post, why not swing across to the Woodland Trust’s ‘Nature Detectives’ site: http://www.naturedetectives.org.uk/autumn/ Lots of free play activities, worksheets and field guides.

There’s not just Autumn-related stuff either, this is a great all-year round resource, with literally hundreds of resources. We’ll cherry-pick (or any other fruit of your choice) some of the most useful in a future post.

The New Curriculum: Y3

Continuing our ventures into dissecting the new science curriculum, here is a detailed look at the changes to be implemented in Y3. This is where things get especially interesting, as Mr Gove et al have given the OK to schools discontinuing the 2000 curriculum in Y3 and 4 as of this month. Effectively, this gives the chance to ease into the new curriculum and maul it around a bit before it’s officially in place. At Primary Scientists, we will be doing just this, and will be recording our adventures in implementing the new curriculum, with accompanying lesson plans and resources.

In Y3,  there are areas which remain essentially unaltered, some which have seen some adjustment, and other units which have been completely added or removed.

Most of the additions are, more accurately, translocations. Interestingly, these areas (forces, sound) have both been moved up from their traditional KS1 homes; also interestingly, they are both Physics. A short rant before returning to impartiality: physics has already been quite poorly covered in many schools; why diminish it in importance further by delaying it so far into the curriculum? There’s also the issue, for the next couple of years at least, of Y3 pupils being “introduced” to concepts they have previously met in KS1.

Rocks and soils is now simply ‘Rocks’. Moving out soils is perhaps questionable, but does allow for some more in-depth and engaging Geological learning and experiments. Of course, such removals on paper don’t mean a wholesale embargo on these areas; indeed it would be hard to not make reference to soils as well, especially as a means of extending G & T pupils.

The Biology components are less drastically changed in Y3, although there is now a thematic focus on transport in both animals and plants.

As usual, we have prepared a detailed table of comparisons between the existing 2000 QCA units and the new curriculum,  available to download here: y3 science curriculum changes. Enjoy!

Primary Scientists Autumnwatch #1: The Small Tortoiseshell

Well, Autumn hasn’t officially started yet, but here we go! These first few weeks of the Autumn term are interesting ones, the interface between the fading summer and the oncoming crisp golden-ness of October making for some great wildlife-watching  opportunities.

Already the days are starting to have that September chill in the air, and soon the numbers of insects will be diminishing. There are several species of butterfly still to be seen ‘on the wing’ into September and October, and in fact these are some of our most colourful and familiar. Today we are highlighting a well-known and popular species, the Small Tortoiseshell.

—-

THE SMALL TORTOISESHELL

Aglais urticae

IMG_0280

One of the most colourful species of butterfly to be seen in Britain, the Small Tortoisheshell is widespread throughout the country. Partly, this is due to the wide availability of its foodplant, the common stinging nettle. However, in recent years it has become significantly less common, with recent studies citing as high as 52% decreases in some areas. There is some speculation that this is because of the spread of a parasitic fly, Sturmia bella, whose eggs are laid on nettle leaves and then ingested by caterpillars. You can read more about a study into this here.

On the bright side, the butterfly seems to have enjoyed a good summer this year, no doubt boosted by our scorching July!

There are two broods of the species each year. Adults hatch in July and August, and can survive not only our Autumn, but winter as well. Although you probablyt won’t see them, they are one of the few species that hibernate, in sheds, outbuildings and eaves of buildings. On warm February days you might be startled to find one of these overwintering specimens flying around your house, having woken prematurely!

The overwintered Tortoiseshells are some of the first butterflies to be seen each year, and breed again in the Spring.

CLASSROOM POTENTIAL

Small Tortoiseshell caterpillars - coming to a classroom near you?

Small Tortoiseshell caterpillars – coming to a classroom near you?

The Small Tortoishell is a great species to use in class supporting life cycles. Caterpillars are easily bred in captivity, and fresh nettles are easy to find to top up their food supply; it’s a great one to rear in your classroom, and the butterflies can be released anywhere. The organisation WorldWideButterflies provides special school rearing packs (as well as lots more) here, which are available from September. Obviously, this sort of project provides lots of great learning opportunities. As well as purely Science objectives, you could work in literacy themes of explanations (the life cycle), instructions (how to care for the caterpillars), as well as poetry, descriptive writing and so forth. As well as learning opportunities, there is the potential to help boost wild stocks of a species not as common as it was.

EXTINCT RELATIVE

Did you know that the Small Tortoiseshell has a much rarer relative?

The Large Tortoiseshell. Picture source: Wikipedia

The Large Tortoiseshell. Picture source: Wikipedia

The Large Tortoisheshell Nymphalis polychloris, is superficially similar, but a paler orange and, you guessed it, larger. It once lived alongside it’s smaller cousin in the U.K., but has been declared extinct here for a number of years. Partly this was due to its more specialised needs; the caterpillars fed on elm trees, much less common than nettles. It hasn’t been seen for certain since the 1950s, although there are hopes for a comeback in the Isle of Wight.

Filippa Levemarks Blog

Blogging from my artstudio in Göteborg, Sweden

Considering Birds

My continuing adventures in the natural world

The Garden Smallholder

A Tiny Farm In A Big Garden

The Dragonfly Woman

Aquatic entomologist with a blogging habit

Beetles In The Bush

Experiences and reflections of a Missouri entomologist