SUMMER SCIENCE SNIPPETS 3

SANDCASTLES

There is something very British about a bucket and spade holiday.

Memories of sandwiches with real sand crunching between your teeth, struggling to get out of that wet swimming costume in one of those home made  towelling tent things - come on I am not the only one who had one surely!!

As a child we often went to Swanage on the Dorset coast and sometimes travelled along to Weymouth where the large sandy beach is a mecca for makers of amazing sandcastles which they create at the start of the season and paint so they last all summer.

Of course most dads thought they could do just as well....mine used to create cars for us to sit in and also huge holes which I seemed to be forever trying to get out of.

My two girls loved making sandcastles with their dad - and as we holidayed in Wales it was easy to see the real thing to model from.
I think we even bought a castle shaped mould - which is cheating really.

Amazingly there is a whole community of sandcastle artists and a huge amount of research goes into what actually makes the perfect model - what sort of sand, how much water, what height and so on.

So here is a little of that knowledge for you to see if it improves your building.

Of course you don't need a beach - a sandpit will work too

You can find a very scientific article here:
http://www.nature.com/srep/2012/120802/srep00549/full/srep00549.html

Here is a great extract about how to create sandcastles from
Sandcastles Made Simple by Lucinda Wierenga, published by Stewart, Tabori & Chang

The list of ingredients for creating a simple sandcastle is short: sand, water and a few digging and carving tools. But that is only the start.......

Sand - The first and most important thing you need to know about sand is that you can't do a thing with it unless it's wet. When you add water to grains of sand, the liquid forms "bridges" that connect the granules to one another. This is why damp sand sticks together, so you can shape and carve it.
Packing down or "tamping" wet sand drains more water more quickly, creating even shorter bridges and an even more solid clump. Sand that has been compacted in this way can be subjected to extreme carving.

Water 
1 Use lots of water. Dry sand in its natural state is lazy stuff. It wants to lie down and spread out into all sorts of nooks and crannies. The good news is that as long as you keep gravity working for you, there is really no way to add too much water. Which brings us to our second rule.

2 Let it drain. If you've ever tried to make the base of a sandcastle by filling a plastic bucket with wet sand and then trying to unmould it, you've seen how important this rule is. With no place for the excess water to drain off, the sand makes a sucking, sticking, vacuum seal with the plastic and it becomes difficult, if not impossible, to remove the bucket.
This is why successful sand sculptors do not use plastic buckets or other closed moulds but build their shapes by stacking handfuls of wet sand or by tamping it down in a topless and bottomless form.

3 Compact the wet sand to form structures. "Pounding sand into submission" is an intuitive and time-honoured method of strengthening and tightening those bridges that hold the grains together. You can use your hands or feet, or even a tamper, to compact wet sand.

3. The building methods

Soft-packing

Soft-packing is how the majority of the uninitiated approach sand.
 Mound up a big pile of sand and stabilise the pile. Using the long handle of your shovel, poke a lot of deep holes into the pile then pour buckets of water into the holes. Stomp on the pile until it feels very solid beneath you. If necessary, go back and poke more holes and add more water.
Pack and shape. Working from the tallest element in your composition, pack the shape with your hands until it feels stable. Take handfuls of moist sand, push them into place and roughly shape them.
Carve and smooth. Using your smoothing tool, smooth and define the elements of your composition. Moisten as necessary. The longer you work on your composition, the more your sand sculpture will dry out – you must keep it moist.You need to keep pushing and smoothing.

Hand-stacking

When you're tired of crawling around a soft-packed sculpture on your hands and knees, you will be ready to try hand-stacking. It takes practice but once you master the mix-scoop-plop-flatten-jiggle move, you'll be building the best castles on the beach. The method is just a modified dribble technique using larger handfuls of sand – very large, very wet handfuls.
Hand-stacking involves scooping out handfuls of wet sand and helping them settle into each other in order to form structures. It's the only building technique in which you mix the sand and water in advance. With soft-packing, you start moulding with dry sand and then add water.
The most difficult aspect of hand-stacking is that it's less intuitive than soft-packing; many people have an instinctual urge to pound the sand into submission. Hand-stacking is a great way to involve the whole family in a sand-sculpture project, with duties evenly divided between "stackers" and "carvers".

Mix Scoop Plop Jiggle

You will soon find that big, fat things are easier to carve then little, skinny things, so build big. To do this, you need big handfuls of sand. You do not need big hands to get big handfuls if you scoop properly.
With one smooth, swift motion (so that you don't lose too much water), plop the double handful of sand on to your base. There may be a bit of "pouring", but a common error to avoid is the "slam dunk". The taller and more delicate your structure is, the more gently you should plop. If you are building a tower, keep your hands on top of the sand; if you are building a wall, your hands will go directly to the sides.
Jiggle. Very gently, jiggle the new pile of sand. The common urge is to force this to happen by pounding, packing and pummelling the sand into compliance. Resist. Instead of using brute force, jiggle or vibrate the sand, helping it to settle evenly on to the layer beneath. Wet sand wants to flow downwards, and as long as you keep it moving, it will continue to settle in on itself, becoming denser and filling in spaces.

Almost as important as understanding how to jiggle is knowing when to stop. When the sand has stopped flowing, further jiggling will form cracks in your structure. Don't jiggle sand that has already settled into place.

There is so much more info on the internet so do some research and find out the fascinating science of sandcastles and maybe you will be building amazing structures like this.....

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Summer Science Snippets 1

A little bit of science fun over the summer months........

We all know the benefits of wearing sunscreen but how often do we either forget or think it isn't really very sunny so don't bother?
How many struggle with young children who for some reason hate being rubbed all over with a cream....I wonder why??


At the moment one well known company is using a UV camera to show how their product blocks UV rays....it looks impressive.


Here is a simple and really fun way to test out your suncream.

These little beads are UV reactive and now you can buy them all over the place.

We have been using them for a few years to demonstrate modern reactive materials along with hydrochromic and thermochromic products.

simple bracelets of UV reactive beads

By exposing the beads to UV you can change their colour from a plain creamy white to a range of brights.

Here we have made simple stretchy bracelets and put part in a clear plastic bag which we then smeared with suncream. The other part we left out in the sunlight.
We used two different SPF strengths - it really does make a difference what strength you use!
See for yourself.........

Brand New Workshop for KS1

We know that KS1 teachers love having us in to do shows and workshops but with the new 2014 science curriculum so many of the things we get up to have moved to KS2 so we decided to make sure the younger scientists didn't miss out by creating a workshop especially for KS1 to complement the show All About You.

Usually when we go to a school with our shows we have the whole school in a number of age appropriate groups but then if there is any time left we will work with class sized groups in workshops. Often this is KS2 so we have added a special workshop for KS1 to our programme.

Our show All About You is such good fun and full of amazing facts about our incredible bodies. When we are working with the younger ones we focus on things that really matter to them such as what can I have in my lunchbag if we are a Healthy Eating school? 

Timmy our 3rd member of the team comes along to helps the volunteers make a lunch bag full of healthy goodies that are good to eat. We have sourced some amazingly realistic prop food so we we pack up our insulated bag for lunch so that we can have some tasty snacks that keep us healthy.
We explore our super senses with feely tubs and grot bags....as you can guess the older ones love going for the grot bags and putting their hands into disgusting goo or slimy snot!!

We take our huge mouth and have a good explore of how to clean our teeth and what all those nashers actually do. Then we actually get a couple of volunteers out to make home made toothpaste and test it against shop bought.

We use our blue cuddly cold virus to talk about keeping healthy and safe from colds and to show how easy it is for colds and other nasties to spread we give a whole class a cold. Helen has the most amazing glittery snot you have ever seen!!

For KS2 we offer tasty toothpaste or bath bombs as a class workshop  and we have decided to extend part of the show about senses and make it into a full workshop for KS1. We have been busy sewing feely bags ( little bags which you put you hand into and try to decide what is inside just by feeling). Helen has sourced strange objects to put inside....nothing too scary but things which feel amazing. 

We have some lovely shakers as sound makers and have an ingenious way to let everybody test their sense of smell with some strange odours!!

Everyone who has tried this new workshop has really enjoyed it so now it has a full place on our programme alongside All About You our show about being healthy. Teachers can now choose to have a workshop with KS1 about Super Senses, with lower KS2 making toothpaste or upper KS2  making bath bombs.