Why do ships float?

RMS Titanic leaves Southampton on 10 April 1912

We all know the Titanic sank, but today Charlie and I were considering the opposite question: why did she float in the first place? After all, she was made of iron and steel. How could she float, let alone be considered 'unsinkable'?

Coming from a humanities background, it was a challenge for me to get to grips with this myself, let alone explain it to Charlie. Frankly, I struggle with words like 'density', 'volume' and 'mass'. Fortunately, I had two things on my side: motivation - and the internet.

In my background reading, I learned that one of the reasons the Titanic was able to float, in spite of being made of heavy metal, is that most of her volume ('the amount of three-dimensional space an object occupies' - see here) was occupied by air, which means the average density of the ship was less than the density of the water. Density is a measure of how solid something is (great, simple explanation here). When the Titanic hit the iceberg, the ship started to fill with water, which displaced the air. Once the average density of the water and the steel ship was greater than the density of the water, she sank (see longer explanation here).

There's another good explanation for adults and older children here.

I told Charlie about Archimedes, the Ancient Greek who discovered the science of buoyancy. We watched a video called: ' How Taking a Bath Led to Archimedes' Principle', which provided a brief and child-friendly description of the famous (although not necessarily accurate) 'Eureka' story.

 
Charlie thought this was funny, but was understandably still puzzled about how this helped a ship to float. I had found several descriptions of Archimedes' principle - such as this one here - but they were too complex.

So we watched some more videos.

 

And more...

We also watched this BBC clip which demonstrated that water is a force which moves on its own and can push and pull.

Then we collected some objects to perform a scientific experiment to see which would float and which would sink. 

 

Before putting the objects in a tubful of water, I asked Charlie to predict what he thought would happen. I wrote this on a worksheet. He then proceeded to place each item in the water. Some of his predictions were correct; some weren't. We discussed why and noted down the results.

 

Now it was time to have a go at making a boat of our own.  For this, I referred to a fabulous online guide called 'Titanic Science'. One of the activities explores buoyancy, using modelling clay. The activity sheet explains that: 

'Liquids exert an upward force on an immersed or floating object. This upward force is called buoyancy. The larger the surface area of the object, the greater the area for the water to push back on. Ships such as Titanic are made out of steel. Put a lump of steel into the water and it will sink. Spread the same lump out into a boat shape with thin walls and it can float.'

So, the density of the clay used doesn't change, but the volume of the object made from the clay increases. This increase in volume decreases the overall density of the object, making it float.
 

Charlie modelled a boat out of clay. 

 Then he rolled up a ball of clay.

 

He dropped both of these onto a tub of water: the ball of clay sank to the bottom; the boat floated. Success! 

Charlie had some fun playing with the clay after this, whilst I made myself a cup of tea. We then curled up on the bed together whilst I read him two children's picture books which take a light, comical look at the science of buoyancy.

 'Mr Archimedes' Bath' is (very) loosely based on the story of how Archimedes discovered the principle of buoyancy. When the bathwater keeps overflowing, he is determined to find out which of the animals who is sharing his bath is responsible. 

In 'Who Sank the Boat', a cow, a pig, a donkey, a sheep and a tiny mouse go for a row in a boat. One of them sinks the boat. But which one could it be?

Charlie enjoyed both these books and it was good to have a lighter perspective on the science we'd been studying today.

 

 

 

 

The Titanic Exhibition at the SeaCity Museum, Southampton

On Thursday, we spent a large part of our day on trains, but it was worth it because they took us to an excellent exhibition: the Titanic Exhibition at the SeaCity Museum in Southampton. 

Over 500 households in Southampton lost a family member on the Titanic. Following the coal strike of early 1912, many people were out of work and there were 17,000 unemployed in the city, so many jumped at the chance of work on board. Many of them had never been to sea before.

During the long train journey, Charlie spent some time reading his new Usborne Titanic Sticker Book, which I had bought as a surprise present for the trip.

 

Although it would be fair to say he spent more time designing his recreation of the Titanic on the Minecraft app.
 

The watertight compartments

The boiler room

We arrived at around 11.30am, which gave us three hours to spend on the exhibition before we needed to catch the train home in order to avoid the rush hour.

View of the SeaCity Museum with the Clock Tower under scaffolding

After we'd paid, we were given a copy of the museum trail for Charlie to fill in as we walked round. He's not usually too keen on these, but this was just the right length: brief enough not to take up too much time.

 

The first room we entered featured several models of the Titanic. Charlie was particularly impressed by one made entirely out of matches by a local model maker, David Reynolds. It had taken Reynolds 300 hours to build.

A second model, made by Charles Lane, featured a notice which set the scene by explaining that the Titanic and Olympic were designed to be the biggest and most luxurious of all the ocean liners offering a Southampton - New York service.

Rounding a corner, we were confronted by this striking display:

 

More than three quarters of Titanic's 897 crew members lived in Southampton in the days before the ship set sail. Some lived in the town, others stayed there before taking up their post on board. 

Three crew members, in particular, are a focus of the exhibition: Captain Edward John Smith; Second Officer Charles Herbert Lightoller; Walter Francis Fredericks (coal trimmer); Mabel Bennett (stewardess); Sidney Sedunary (Deputy Chief Steward); and Archie Jewell (lookout).

 

Walking past the photographs, we were transported into a street in 1912, complete with the sounds of the city. Old films and display cases featuring artefacts of the time added to the atmosphere.

The words and pictures tied in neatly with our discussion about the class differences of the time. 

 

We discovered a wardrobe full of children's dressing-up clothes, but Charlie was reluctant to try them on. My enthusiasm at photographing him all dressed up probably didn't help. He couldn't resist trying on a life jacket though, so I got my photo in the end.

 

There was a lot to see in the next part of the exhibition, which was very skillfully laid out and with plenty to keep children and adults entertained.

Lots of touchscreens

The White Star Line flag

A number of artefacts

Original film footage from the time

Paintings, such as this one by George Fraser, painted in 1912

A particularly striking display was of the Olympic's grand staircase with carved wooden panel, similar to the one on Titanic.

The next section was fantastic for children. Charlie wanted to try everything. First, there was a chance to stand on a recreation of the Titanic bridge and steer the ship.

Then the boilers needed stoking...

And, finally, there was a reproduction of the Marconi room, featuring interactive panels cleverly disguised as papers on a desk. It should have been possible for Charlie to have a go at sending Morse code, but the headphones were missing, so he had to give that a miss.

We were also able to look inside a replica of a second-class cabin, which gave us a real sense of looking into the ship itself.

We were thoroughly enjoying ourselves, but the next room brought us up short: the Disaster Room. I had been forewarned about this because it was mentioned in the children's trail, so I asked Charlie if he wanted to stay and listen to survivors talking about the disaster or to move on. He was in no doubt that he wanted to skip this bit, so we moved straight on to the next room. This had a sombre feel, as it was all about the aftermath of the disaster. At least it included lots of survivors' stories and pictures, which brought some comfort. 

The final room covered the inquiry and Charlie wasn't interested in this at all, so I suggested a quick visit to the gift shop, followed by lunch, to which he readily agreed.

After a sandwich and drink, we decided to have a brief look at the rest of the museum before starting our journey home. Charlie was distracted by this machine, artfully placed in the foyer, and I let him choose a penny to stamp.

He chose the Titanic stamp, of course.

We both wanted to see the large-scale model of a liner that I had seen online, whilst reading about the exhibition. It turned out to be a model of the Queen Mary. Charlie was impressed by the size of it.

During our brief exploration of the museum's other main permanent exhibition, 'Southampton: Gateway to the World', we found out about the emigrants who have passed through Southampton on their way to a new life or seeking a new life in our country. This supported our earlier discussion about emigration. I even found an exhibit similar to the 'What would you pack in your suitcase?' worksheet Charlie had filled in at home.

Charlie chose a jar of Marmite, a shirt and a teddy

By now, it was time to go home. Somehow, the journey home felt even longer than the journey out, but we passed the time playing games, reading and dozing. 

I was pleased that Charlie had mostly completed the museum trail, so we had something to put in his Titanic project book, alongside our photos. He doesn't much like writing, so I wrote his answers for him for a couple of questions.

 

Once home, Charlie presented his Dad with a bottle of Titanic Iceberg beer from the museum gift shop, a present that was gratefully received.

We had a great day out and I would thoroughly recommend the exhibition to anyone interested in the history of the Titanic.

Our project on RMS Titanic

  

This week we started work on our project on the Titanic. Although this has taken up most of our time, Charlie has also continued with his daily cycling practice sessions. He is getting really good and is so proud of his new skill.

I have also made sure he continues with daily Maths. He is still doing ConquerMaths and enjoying winning his certificates as he progresses through the levels, but he has also returned to the MyMaths website, as he finds some of the games really fun.

All other subjects have been incorporated into our current topic work on the Titanic. During the summer holidays, Charlie learned about the Titanic story by reading the 'Magic Tree House' books on the subject. Tonight on the Titanic by Mary Pope Osborne is the story of how Jack and Annie end up on the Titanic on the night of the disaster. The accompanying book, Titanic: Fact Tracker by Will Osborne and Mary Pope Osborne, provides the factual background. Both books handle the tragic element with a sensitive touch, making them suitable for young children. Charlie, who is eight, found them interesting and easy to read.

During the holidays, we watched 'A Night to Remember', a British film adaptation of Walter Lord's book of the same title about the Titanic disaster. Made in 1958, this film is still held in high regard by Titanic historians. Several Titanic survivors acted as technical advisors. There are a few historical inaccuracies, such as the portrayal of the ship sinking in one piece (which contradicted the reports from some survivors), but, on the whole, the film is considered a faithful account of the event.  

 

Charlie enjoyed the film, but told us he didn't like "the sad bit" and left the room at this stage, only returning to see the ending.

We began our studies this week by looking, once again, at the Titanic pack I had ordered online. I would recommend this to anyone doing a project on this subject. It includes:  replicas of a distress telegram ('We have struck iceberg sinking fast come to our assistance'); posters by the White Star Line; a second-class menu; a letter written by a passenger, postcards, a passionate letter from a General Workers' Union protesting at the loss of life of third-class passengers and many more fascinating artefacts.

Charlie spent a long time poring over everything in the pack. I think the documents provided a sense of immediacy to an event that, until then, had seemed to be just an exciting story.

 

After this, we read 'Story of the Titanic' together. This book, published by Dorling Kindersley, provides an overview of the story from the construction of the ship to its sinking. The illustrations by Steve Noon provide cutaways that give glimpses of life on board the ship. Charlie particularly enjoyed finding the tiny vignettes that were hidden in the pictures.

Reading about how the ship was constructed with 16 watertight compartments inspired Charlie to have a go at testing the science behind it. He learned that the Titanic was designed to stay afloat if any two compartments, or the first four, were flooded. Unfortunately, the iceberg tore a hole in the first six compartments, making it impossible for the ship to stay afloat.

Charlie created a Lego version of the ship, complete with individual compartments under the floor. Obviously, Lego is not watertight, but testing it in the water gave him an idea of how his boat could stay afloat with one compartment flooded, but not with more than one.

At the start of each of our days studying the Titanic, Charlie worked on his handwriting. It was easy to find relevant worksheets. I downloaded these, for free, from ESL Writing Wizard, a website that provides free handwriting worksheets on a variety of topics.

Another worksheet incorporated blank clock faces, as well as words, so that Charlie had a chance to practise telling the time as well. This one came from Activity Village, which has a variety of free worksheets and colouring-in pages about the Titanic.

Yesterday, we looked at what life was like just over 100 years ago. We began by watching a video featuring songs and film from 1912.

Then Charlie cut out some paper dolls and dressed them in the upper-class fashions of the time. He very much enjoyed this. I found the dolls - Lady Beatrice and Lord Philip - on this blogsite.

I explained a little of what life was like in 1912 and then Charlie compiled a page filled with pictures and information snippets from the period. He made a cardboard pocket for the paper dolls, decorated it like a bedspread and put Lady Beatrice and Lord Philip to bed, with their costumes neatly tucked behind them.

I had found a useful mini history project on a website called historyonthenet. It featured lots of printables on the Titanic, including crosswords, word searches and quizzes, but I chose to explore the subject of why people thought the ship was unsinkable, which gave us a lot of sources to examine and looked at the importance of historical evidence. The link is here and you can find a printable PDF document by scrolling down the right hand side under 'Downloads'. 

Today we looked at the subject of emigration and why so many people on the Titanic had been leaving their homes to move abroad. 

 

I focused, in particular, on the story of the Addergoole Fourteen, who left a village in County Mayo, Ireland, to start new lives in America, travelling on the Titanic. Only three out of the fourteen survived. Their families were grief-stricken and also left in terrible poverty, as they had paid for the voyage, hoping that their relatives would send money back to them once they established themselves in America. The village still commemorates the loss of its inhabitants by ringing a bell at 2.20am on the morning of 15th April, the time when the Titanic sank. Many of its bell ringers are direct descendants of the Addergoole Fourteen.

Inspired by this story, Charlie thought about what he would take with him if he had to leave his home and drew the items in a suitcase (worksheet printed out from Activity Village, as above).

Later, whilst I was busy, Charlie designed a recreation of the Titanic disaster using bits and pieces from our art box. He stuck a lollypop stick to the ship so that it could sail along the sea and then sink. We filmed it and then photographed it and he was very proud of the result. As he should be.

 

The next project he has initiated is to recreate the Titanic on Minecraft. This is an ambitious project and is going to take him a very long time. 

Maybe I'll have time to put my feet up for a bit.