Friday, 27 September 2013

Different Ways with the Water Cycle

Our river study naturally leads to learning about the water cycle.

A 50p charity shop find of a strategy game based on river tides.

It is truly amazing to discover the interconnectness of various seemingly random topics, but somehow we have been able to stretch our themed study of The Wind in the Willows further and further.  The rest of the series can be found here.

Desk Learning
We started off by printing off the water cycle exercise from here.   First, Tiger matched the labels to their definitions, followed by labeling the diagramme.

Since we had not covered water cycle formally before, I wanted to use the exercise above to gauge how much Tiger knew or didn't know, so that we could focus our efforts on learning new things rather than unnecessary repetition.  When Tiger needed a bit of clarification on the processes, we watched the clips here and here.

Finally, we worked through the section here for review and to test our understanding of this topic.

Hands-on Experiments
Enough of table-learning!  Time to get some hands-on work done so we did a few experiments related to our topic.

1) The classic experiment

  1. Bring a pan of water to boil.  Observe the air bubbles in the pan and the steam (photo 1).
  2. Put a few ice cubes in a foil tray and hold it above the steam - be careful not to get burned by the hot steam! (photo 2)
  3. photo 3: Observe the moisture that forms at the bottom of the foil as the warm air meets the cold foil surface. (photo 3)
  4. As more steam/vapour gathers on the bottom of the foil, the water molecules gather to form bigger drops which eventually fall. (photo 4)

2) Water cycle in a bottle

  1. Cut the neck of the bottle and screw the cap on tightly.  Pour a cup of warm water into the bottle and place the top of the bottle as shown.  Use cellotape to seal the space where the two parts of the bottle meet.  Place the bottle under direct sunlight for 5 minutes.  Think about what will happen to the air temperature in the bottle as it is exposed to the sun.  Observe the inner surface of the bottle and the bottom of the funnel (we observed some condensation on the sides of the bottle but none on the funnel). (photo 1)
  2. Put some ice cubes in the funnel and observe for 10 minutes.  Think about what's happening to the air temperate around the bottom of the funnel. (photo 2)
  3. After 10 minutes we observed condensation on the bottom of the funnel as well as on the sides of the bottle. (photo 3)

3) How raindrops form

Another simple and potentially safer way (compared to experiment 1) to observe "raindrops" forming.  This simple experiment is done by pouring enough water into a jar to cover the bottom, then place a few ice cubes on the inside of the lid and put it over the mouth of the jar.  After 10 minutes you'll see water droplets forming on the underside of the lid.  It works on the same principle as experiment 1: water vapour (from the room-temperate water at the base of the jar) rises in the jar then condenses as it touches the cool underside of the lid.

4) How water droplets gather in clouds

This experiment expands on the previous one (experiment 3).  Tiger first squeezed many separate drops of water onto the inside of a plastic lid, then quickly turned the lid over.  He then used the tip of a pencil to move the tiny drops of water together.  What he observed was the drops seemed to pull one another together to form larger drops.  When the drops are quite big, they fell.

The attraction of the water droplets is due to water molecules having a positive and negative side, similar to how magnets attract each other at opposite poles.

5) How the Water Cycle Purifies Salt Water

  1. Stir 1 tsp of salt into a glass of clean water.  Dip your fingertip into the salt water and taste it. (photo 1)
  2. Add several drops of food colouring (we used red, blue, and green) into the salt water and stir it well. (photo 2)
  3. Put the cup in a ziplock bag and zip the bag up.  Place them in the sun.  Observe the bag every 5 minutes for any changes. (photo 3)
  4. After 15 minutes, we observed some colourless condensation inside the bag.   We also tasted it and found it to be tasteless. (photo 4)

Field Trip
We attended a workshop at a water treatment plant where the children were given a quick overview of the water cycle.  As the workshop was conducted at a water treatment plant, the water cycle exercise included an extended part about how water is collected and treated before becoming clean enough to come out of taps in people's homes.

The children also spent some time investigating changes in the types of organisms found in rivers and water supply due to changes in the level of pollution/industrialisation over time.

Next, it was time to head outside for a tour of the premise. 

A disused filter bed.  You can still see the water tank and pipe from Victorian times.

Much of what we saw were historical -- what the Victorians used for filtering the water supply to London.  For example, we went to an area called the Central Wellhead, which was where the cleaned water (after flowing through the pipes onto the filter beds from the surrounding reservoirs) was stored before being pumped into the water mains.

What I found to be most interesting was seeing an area of preserved filter beds.  The centre has allocated several beds to be preseved in different stages to show they changed over time.

Open Water - This filter bed looks much as it did when it was actively being used.
5 years on - When the filter bed was abandoned, the water level began to drop.
10 years and more - As more sand and gravel was exposed, the plant cover become more densed.
Deeper water - Not all the water drained away from the filter beds.  Tall water plants like reeds will grow where deep pools of water are retained.  Reed beds create a different type of habitat for birds.

25 years and more - Much of the water would have drained away, causing a wet meadow to develop.
30 years on - If the filter beds were no longer managed in any way, ash, willow, and elder trees would eventually grow on them, thus creating a woodland habitat.

The children were shown a simplified version of the filtration process using soil, bottle and water.  I wanted Tiger to conduct the experiment himself rather than passively watch someone else do it, so we did the same experiment when we got home:

  1. Use the same bottle as in experiment 2, but this time remove the lid and cover the inside of the funnel with a piece of coffee filter paper. (photo 1)
  2. Fill the coffee filter paper about 3/4 ways to the top with sand. (photo 2)
  3. Dampen the sand with some clean water. (photo 3)
  4. Mix soil and water together a jar. (photo 4)
  5. Pour the muddy mixture through the sand carefully. (photo 5)
  6. Observe the clean(ish) water being filtered into the bottle. (photo 6)
By conducting this simple experiment at home, we could see the filtration process up-close.  Even though we knew what result to expect, we still found it fascinating to see muddy water become clear water collected in the bottle.

This post is linked up to:
  1. Look What We Did
  2. History and Geography Meme #92
  3. Collage Friday: Signs of Fall
  4. Entertaining and Educational - Sept 27
  5. Field Trip Friday Link Up
  6. Homeschool Review and Resource Link-Up
  7. Weekly Wrap-up: The One with a Little Encouragement
  8. Science Sunday: Learning about Muscles
  9. Hip Homeschool Hop - 10/1/13

Wednesday, 18 September 2013

Digging Up the Past

As we are on the topic of river, learning about its uses and features, it naturally follows that we ought to know a little about the history of the River Thames.  We also watched this documentary that takes a humourous look at some of the industries that flourished along the Thames from its source to its mouth in London.

The Thames, being the largest archaeological site in London, is of great interests to us in terms of its applicability to what we consider to be the 'practical' side of historical study, i.e. archaeology.  We watched the 10-part series of the Thames Discovery Programme to gear ourselves up for an actual exploration of the richness of the site:

Once we were ready, we went to the National Maritime Museum for an archaeological session on the Thames, just like a junior version of the Thames Discovery Programme.

The weather was quite good when we arrived so we spent some time outdoors surveying the site.

  • The tide was fairly high for our purpose of going on to the foreshore for digging (photo 1 above) so our workshop leader decided that the actual dig would take place in the afternoon when the tide would be further out.
  • The children were given copies of  old paintings of scenes along the Thames (photo 2) to make comparison about what they saw in the paintings with what they saw today, as well as to identify some of the landmarks that were depicted in the paintings.
  • One of the landmarks in the paintings was the palace courtyard that we were standing in (photo 3), which dated back the Tudor period.
  • The ground that we stood on has the remains of the foundations of the Tudor palace which was the birthplace of three Tudor monarchs: Henry VIII, Mary I, and Elizabeth I (photo 4).   We were told that parts of the Tudor palace foundations have been discovered recently on the foreshore by archaeologists so there is still more to be discovered later in the afternoon when we would dig on the foreshore.

While we waited for the tides to go out, the children were engaged in various activities indoors:
  • They were given the task of putting a pictorial puzzle together, in the sequence of the source of the Thames to its mouth (photo 1).  The puzzle wasn't too difficult, but Tiger was glad that our preparation at home enabled him to solve the puzzle very quickly.
  • The rest of the indoors time was spent on classifying artefacts found in the Thames from previous archaeological sessions in a number of ways:
    • by materials, e.g. metal, glass, wood, leather, etc (photo 2)
    • by usage: pipes, wall tiles, roof tiles, floor tiles (photo 3)
    • by time period: Roman, Medieval, Tudor & Stuart, Victorian & Industrial age (photo 4)
The tides were out in the afternoon so the children spent a good two hours combining a section of the foreshore.

There was indeed a lot to be found on the foreshore (photo 1 below).

  • After two hours, everyone gathered up their finds on to a sheet of tarpulin for identification (photo 2 above).  After the indoor session where we learnt how to classify different objects by their time periods, there was still much to learn about identification of actual finds, especially different types of tiles.
  • Most of the finds though, were animal bones (photo 3).  The presence of so many bones, as explained by our workshop leader, is due to the numerous pubs and butchers that operated along the river in the Victorian times.
  • Much of our find were from the Victorian period, which makes a lot of sense if you think that it was only about 100 years ago.  The Victorian dock on the foreshore (photo 4) is another evidence of the recent yet long history of activities along the river.
The day before the trip, Tiger was very concerned about whether he could keep the things he would find during the dig.  I wasn't sure what the rules are about keeping items found along the river so I told him to be prepared for the answer to be no.  He was most pleased when the workshop leader told the children that they could keep anything they found, as long as the item isn't rare or precious.  The Thames is so actively excavated that I would be surprised if anybody unearth anything that someone else hasn't already found!  Nonetheless, my boy was just excited to be able to take home his own archaeological finds.  Even if they are just a few broken tiles or some cattle bones thrown into the river by a Victorian butcher, Tiger's finds are precious to him.

When we got home, I put his finds into a tray, washed and disinfected the items several times with sterilising fluid before I felt they were safe enough to be handled.  The Thames is not the cleanest river in the world by any measure.

Once the items have been cleared of killer germs and any potential nasties, we got down to the business of sorting out Tiger's "treasures".

We tried to replicate the experience we had in the indoor classrom at the Martime Museum by first classifying the items by their materials:

Then we tried to identify them by their time periods.  The video here gives a very good overview. 

It was difficult to recall the exact information on how to use the different pottery patterns to tell whether they were from the Medieval period or from the Tudor/Stuart periods, so we looked up the information here and here.

Medieval pottery
Stuart pottery

Bones, pottery, glass, shells - all from the Victorian era

The Victorian era finds warrant a closer look, not only because they make the greatest number of our total finds but also because they belong to a time period that we can still find plenty of evidence around in England.

We found a portion of a Victorian wooden nit comb (photo above), which has to be kept in water to prevent the dried wood from disintegration from exposure to air.  How do we know it's Victorian?  Because:
  1. It's made of wood so it couldn't have been from a later period.  By the Industrial Age, people have started using metal combs.
  2. Being found in the river, it couldn't have been earlier than the Victorian period otherwise all of the wood would have rotted away by now.  The nit combs portions from the Roman period (that we have seen in museums) are either made out of bones or if they were made out of wood, have been found in fields, not in rivers.

  • photo 1: leather.  This looks like part of the sole of a shoe.  In Victorian times most people tried to recycle leather as much as they could before throwing it away.  As such, a piece of leather would have gone through several uses from being part of an item of clothing (most probably a belt) to being the the shoe soes.
  • photo 2: oyster shells.  The presence of a large number of discarded oyster shells in the Thames tells us quite a bit about the Victorians' love for oysters, as they were readily available from the pubs that operated along the river back then.  The precise square and circle cut-outs from the shells were made to use them as mother-of-peral buttons on Victorian clothing.
  • photo 3: cattle bones.  From the sizes and shapes of these bones, they are likely to have come from a big animal like a cow.  The possible explanation of them being in the Thames is that they were discarded by the butchers and pub kitchens that operated alongside the river in Victorian times.  We watched this clip to learn a bit more about identifying bones from an archaeological dig.
  • photo 4: Victorian glass bottle.  The thickness, opaqueness, and dark green colour of the glass are clues to it being made before the Industrial Age.  The curvature of the bottom of the glass is what reveals itself to be from the Victorian era.  In Victorian times, wine bottles were made with a concave bottom to hold wine sediments.
  • photo 5: various tiles.  The pigmentation and colours of the tiles are important to identification.
  • photo 6: clay smoking pipes.  These are part of the smoking pipes that were used in the Victorian times, when tobacco was first brought into England from America.  Because of the way they were made, the clay pipes found are usually broken into at least two pieces.  The picture below shows what a clay pipe would have looked like in its unbroken form:

This post is linked up to:
  1. Hip Homeschool Hop - 9/17/13
  2. Look What We Did
  3. History and Geography Meme #91
  4. Collage Friday - The Simple Gifts are the Biggest Blessings
  5. Entertaining and Educational - Sept 19
  6. Homeschool Review and Resource
  7. Field Trip Friday
  8. Weekly Wrap-up: The One with Birthdays, Flowers, and a Little OCD
  9. The Homeschool Mother's Journal {September 21, 2013}

Friday, 13 September 2013

The River Dwellers

When first studying the freshwater habitat of the river, we wanted to find out what creatures live in or by the river (apart from the four main characters in The Wind in the Willows).

It is not easy to get a sample of organisms from a flowing river, so we managed to get some samples from a closed-off tributary.  As such, the experience and resulting organisms studied were more similar to that from a dip in a pond.

Using an identification sheet, Tiger identified his catch from several attempts of dipping around the "pond".

There were the usual water fleas, water snails, water boatmen, and worms (photo 1), but the most exciting catches for day were:

Our main animal interest from the story is, however, on the four main characters:
  1. Badger
  2. Toad
  3. Mole
  4. Ratty (water vole)

There are no major surprises when we studied these animals, until we came to the badger.

There is currently a highly-charged emotional affair concerning the badger cull in England.  The issue of whether killing the badgers is an effective way to control the spread of tuberculosis in cattle is still unclear, and I remember that badgers were a protected species not so long ago.

Caution: The clip below has a few scenes of badger shooting that some people may find disturbing.

Having heard enough of the unhappy cull, we decided to take a walk along another river.

We wanted to see whether we could find the likely spot for Ratty's home by the river bank.  There were many possible places for a water vole to call home, but we didn't see any since the river was busy on that day with boats and people along the bank.

Here's a good spot.
Here's not too bad either.

Hoping to see otters, Tiger looked hard and took notes of what he saw.

We didn't see any otter, but we saw a few things that were noteworthy.

Here's a glimpse of Tiger's notes (with his permission):

It says "sizeable fish.  Ducks are catching fish (see 1).  3" - 5" crayfish!  alive!"

Yes, that's right.  We saw a crayfish (photo 1 above).  We couldn't believe our eyes.  It wasn't moving so we could not be sure whether it was still alive.  Its claws are red, which means it can't have been the white-clawed crayfish so we really don't know which freshwater crayfish it is.

We also saw damselflies mating on the grass (photo 2), as well as many water birds (including the Canada geese - photo 3) swimming and feeding along the river.  The river looked very clean and was teeming with life, with many fish swimming in it.  The Mallard ducks, as noted by Tiger, were in a feeding frenzy.  I had not seen them behave like this before.

Tiger wrapped up his work by making a simple river habitat accordian book using the template from this book.

This post is linked up to:
  1. TGIF Linky Party #94
  2. Collage Friday - Latin and Fire Pits
  3. Entertaining and Educational - September 13
  4. Weekly Wrap-up: The One with the Curriculum Update
  5. Country Kids: Blackberry Picking
  6. The Homeschool Mother's Journal {September 14, 2013}
  7. Science Sunday: Studying Bones 
  8. Look What We Did
  9. Weekly Homeschool Review and Resource Link up: September 13
  10. Hip Homeschool Hop - 9/17/13
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