Water, Water Everywhere

It is still raining quite a bit where we are.  We have been measuring the daily rainfall using our homemade rain gauge.

The amount of rainfall that we get is nothing compared to some parts of the country.  It started with heavy rainfall in December, building up to floods occuring in many parts of the country by early January.  We have been looking at the photographs here, here, and here to see the damage and inconveniences caused by having too much water.

To get to the bottom of things, we decided to find out what might have caused the extreme weather, specifically the factors that might have led to flooding:

Naturally, being near a river is going to be a concern at a time like this.  However, river flooding doesn't necessarily have to become hazardous, if proper planning and management have been done to make use of the sediments deposited by the flood water, as we have learnt two years ago in world history -- where the flooding of the River Nile was a major source of the fertiility of the lands around it.  Below are some phots of the experiment we did to illustrate the flooding of the Nile leading to fertile land.  We used planted grass seeds in an aluminium tray, flooded the "river", and waited for a week for all the water to be absorbed and the grass to grow.

The Thames is a tidal river, hence very susceptible to flooding.  Having London flooded would be extremely costly, hence the Thames Barrier has been very much in use these few weeks to make sure that doesn't happen:

Apart from rivers being a potential source of flooding, coastal flooding can be lethal too:

The force of water can be illustrated by making a simple water wheel using plastic cups and paper plates.  It works but isn't very robust, being made out of paper plates and all, so the rain made it very soggy after a few hours.  Nonetheless, it served its purpose before it disintegrated.

It seems that the trouble is going to persist for a while yet...

For anyone who is living in a high flood-risk area, it's probably a very good idea to learn from here all about how to prepare for a potential flood, what to do during and after a flood, and how to manage flood risks.  Alternatively, much can be learned from books too.

This post is linked up to:

1. Geography and History Meme: Ancient Egypt activities for kids
2. Entertaining and Educational - Hasty Pudding
3. Collage Friday: The Key to Successful Homeschool
4. Weekly Wrap-up: The One with the Love Languages, Too Much Castle, and New Curriculum
5. Homeschool Mother's Journal {January 25, 2014}
6. Science Sunday: What Do Your Students Need to Know Before High School - Biology
7. Hip Homeschool Hop - 1/28/2014

Water is Super Cool!

Since there has been so much rain, we continue our rain study by using a science kit that we had picked up at a charity shop that is relevant for our purpose.

There are 25 experiments to do with this kit, but not all provide new learning experience for us so we only did those what looked interesting and taught us something new.

1) Density
The first experiment we did was to find out whether all liquids weigh the same.  To do that, we prepared two jars of warm water -- the jar on the left has several tablespoons of salt added to it.

We then gently put each egg into the jar.  The egg in the salt water jar floats because salt water is denser than plain water, so the weight of the egg does not have to push away or displace as much water to make space for itself (compared to the egg in the plain water), therefore it floats.

 

I think this can also be explained by the differences in molecular structures between salt water and plain water, but we will come to that when we learn more of chemistry.  For the moment, the above simple explanation is enough for us.

The next experiment has to do with mixing oil and water.  First, Tiger half filled a glass with cooking oil, then topped it up with plain water.  He observed that the oil found its way up the glass and floated on top of the water.  This is because water is less dense than water.

2) Temperature
We wanted to find out whether salt affects the freezing point of water, so we filled two containers with cold water and added a teaspoon of salt to the one labelled with "S".

 

Both containers were put in the freezer and checked every 15 minutes for their stages of turning into solid.

Ice crystals started forming in the plain water container after 30 minutes, while nothing happened with the salt water in the same duration.  After 90 minutes, the plain water had become solid ice while the salt water was still in liquid form.

3) Supercooled Water
The coolest thing we found out was about supercooling.  The gist of it is to bring water to a temperature below freezing point while maintaining its liquid form, then turn it into frozen ice instantly.  In the natural world, this phenomenom happens in the clouds in the northern hemisphere during winter for rain to form.

It is too cool to miss, so we decided to try it out for ouselves.

Alas, the cool factor eluded us.  We couldn't make the experiment work despite numerous attempts.

Apparently, achieving the desired result isn't so easy after all, according to the clip below.  Phew, that made us feel less incompetent.  The clip also explains what is happening to the molecules during the process:

4) Surface Tension
This is an experiment where we made a cascade of slow flowing water using the attraction of water molecules and surface tension.

We wet a piece of cotton string then tied one end of it to the jug handle.  The jug was filled with water.  The other end of the string was held taut against a small jar.  Tiger then lifted the jug so that the string passed over the spout.  The water was poured gently.  If you look carefully in the clip here, you can see the water flowing along the length of the string into the jar.

The reason for this observation is because the wet string attracts the molecules in the water while the surface tension creates a skin on the outside of the water.


5) Absorbency
The activities we did at home were supplemented with a hands-on workshop at a water treatment centre where the children did additional experiments related to water and recycling.

A simple experiment is to drop a few drops of water onto different types of materials to find out which material is the most absorbent.

The next experiment investigate three factors at once:

1. which type of earthy material (gac, sand, or gravel) is the most effective for filtration;
2. which type of earthy material (gac, sand, or gravel) is the most abosrbent.
3. which type of earthy material (gac, sand, or gravel) is the most permeable.

6) Recycling
As the facility we went to is a part of a water treatment centre, recycling naturally forms part of the education programme that was on offer.

One of the experiments the children did was to find out why they should only put toilet paper (rather than other paper materials) down the toilet.

1. To do this, three pots with plain water were prepared.  A piece of different material (toilet paper, tissue paper, wet wipe) was put into each pot.
2. The pot was then sealed and the children shook each one vigourously for 5 minutes.
3. The children then examined the contents of each pot to see the different degrees of disintegration that has occurred.  We found that the toilet paper broken down the best, followed by tissue paper.  The piece of wet wipe did not break down at all.

The children also had a go at paper making using torn up pieces of waste paper.

This post is linked up to:

1. Entertaining and Educational -1700's Wig
2. Collage Friday - Infinite Value and Learning in Each Moment
3. Weekly Wrap-up: The One Where We Got Back to School
4. Homeschool Mother's Journal {January 18, 2014}
5. Science Sunday: What Do Your Students Needs to Know Before High School Chemistry
6. Hip Homeschool Hop - 1/21/14 

Rain, Rain, Go Away

Has anyone else in the UK noticed that there's been a lot of rain around us lately?  In my typical fly-off-the-seat-of-my-pants approach to learning what catches our interest at any given moment, I thought it would be most relevant to learn more about rain.

For example, why does it rain?

We also learned that rainfall can be measured using the high-tech way via radar, or the low-tech way of a rain gauge:

Since the low-tech rain gauge looked simple enough to do, we decided to make one ourselves following the instructions here:

This is our version, which according to the explanation here, may not be yield the most accurate measurement since the top and bottom widths of our rain gauge are not exactly the same.  Nonetheless, it serves as a rough and ready version to give us a sense of how much rainfall there has been.

Since it has been so wet, we thought it would be interesting to learn how to measure the humidity in the air at any given moment:

Compared to the natural, pinecone hygrometer we made a few years ago, the bottle hygrometer we've made this time offers us a more accurate reading of the relative humidity in the air.

By putting the readings that we got off of the wet bulb (3 degrees Celcius) and dry bulb (11 degree Celcius) into the computation website found here, we can see immediately that the relative humidity of that day was 17%.  We think that is pretty cool.


This post is linked up to:

1. Nature Study Monday: January 2014 NSM! Link Up
2. Geography and History linkie #1
3. Entertaining and Educational - Atoms
4. Collage Friday - No Spend Month, Marriage, Menus, & Miscellany
5. Weekly Wrap Up: The One Where Dad Was Home
6. The Homeschool Mother's Journal {January 11, 2014}
7. Science Sunday: The Difference Between a Science Demonstration and a Science Experiment
8. Hip Homeschool Hop - 1/14/14

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

Procedure:

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

Procedure:

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

Procedure:

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:

Procedure:

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