Boats and Ships STEM Activities

Boats and Ships STEM Activities

We have just finished a huge Edwardian Era study covering lots of different subjects. Last term our focus was on the Wright Brothers and flight; this term it has been the Polar Explorers (who sailed to the Antarctic in ships) and the Sinking of the Titanic (which, of course was a ship!). Handily, this led to a whole separate study into sailing, during which we carried out many boats and ships STEM activities.


This book was an excellent addition to our studies. I read the whole book out loud to the girls, and we completed many of the suggested ships and boats STEM activities. The instructions were clear, the pictures numerous and the book as a whole was very interesting.

Our second resource was one I had found during our polar explorers study:

The Polar Explorers’ resource contained extra boats and ships STEM activities. These were very simple and easy to follow, using items anyone would have around the house.

Boats and Ships STEM Activities

Measuring the Density of Water

For this activity, we made a simple hydrometer using a straw, a marker and some non-hardening clay. Two glasses were filled with water. Salt was added to one of them until saturation. The girls placed a small ball of clay onto the end of the straw and placed it into the pure water. They marked the level of the water on the straw with a permanent marker. The girls then placed the straw into the second glass with the salted water. They marked the level of water. The two marks were compared:

The girls surmised that the added salt increased the density of the water. This caused the ball of clay to sink lower in the fresh water than it did in the salty water (as demonstrated by the permanent markers).

Testing the Upthrust of the Water

I gathered a marble, a wooden block, a large polystyrene block and a small polystyrene block. The girls placed each of them in the water. First, they added the marble and it sank. Second, they added the wooden block and half of it was submerged by the water, but it did float. Lastly, they placed the polystyrene blocks in the water. They floated completely on the surface. The girls took it in turns to push the polystyrene blocks down into the water. They noticed that it was harder to push the larger block down compared with the smaller block:

The girls surmised that the upthrust of the water wasn’t enough to make the marble float because it was so heavy. They thought the wooden block floated less than the marble because it was less dense and less heavy, and the upthrust of the water was enough that it supported the wooden block and stopped it from sinking. The polystyrene blocks floated upon the water because they were much lighter and exerted a much smaller downward force on the water. The larger block was harder to push under the water because it experienced more upthrust than the smaller one.

Making a Hollow Hull

For this activity we needed a sheet of foil and some marbles. Oh, and the bowl of water from the previous activity. Becca placed the flat foil in the water and pushed it down slightly into the water. It sank easily because it does not displace much water so there is little upthrust. The girls then crafted a simple boat from the foil and placed it into the water. It floated, even after giving it a similar push downwards as the flat foil was given. The shape of the boat means that it pushed aside more water than the sheet, and thus the upthrust is greater. The girls added some marbles one at a time until the boat sank:

We chatted about the simple boat being a little like a hull. Being hull shaped and filled with air gives the boat a much lower overall density. As the girls placed marbles into the boat it sank lower and lower into the water. Eventually, it sinks.

Design a Boat

The girls used some non-drying clay to design a boat with a shape they thought would hold the most amount of raisins:

Abs managed about ten raisins whereas Becs managed 83 raisins! We talked about different shaped boats and why Becs’ was stronger than Abs’ boat: the shape of the boat effects the weight it can carry. The more water the boat displaces, the better it will float and the more cargo it will carry.

Loading Cargo

In this activity, the girls discovered the importance of a weighted hull and balancing the load equally throughout the hull.

The girls added five coins to one side of the hull. The ‘boat’ tipped over on that side. Adding five coins to the other side balanced the ‘boat’ out again:

We then weighted the bottom of the hull with four separate and evenly spaced coins. The last three pictures show the lean after seven coins, after fourteen and finally achieving the same lean as the original five coins after placing twenty one coins!

From this activity, the girls could see how important a weighted hull was to the stability of the boat. They also demonstrated how important it was to balance the load when adding cargo to the ship.

Investigating how the shape of the hull affects how smoothly it moves through the water

This was a lovely demonstration of how the shape of the hull affects the ease with which it passes through the water. I made the boats from coloured card and gaffs tape to waterproof it. We also needed three weights, three paper clips and three pieces of string of exactly the same length:

The girls attached the weight to one end of the string and the boat to the other:

Boats and Ships STEM Activities

We also used a storage box full of water. You could use a tank or a bath or sink, or even a cat litter box. The girls lined the boats up in the water with the weights hanging free over the floor:

They let go of their boats at the same time and…

Both Abs and Becs had predicted that the pointed shaped hull would move the fastest through the water and the square shaped hull would be the slowest. They were right!

We repeated it numerous times and found the same each go.

There were many more activities to do in the book, but we ran out of time. Nevertheless, the girls had fun and learnt lots!

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