Holywell Primary and Nursery School

Why Do Steel Ships Float? Year 5

5MH Learn About Water Resistance:

On Monday 6th November we started to learn about water resistance and up thrust.

We measured a variety of objects using Newton Meters to get an accurate reading of each objects force.  However, as Andreas is demonstrating, if you rest the object in water, the amount of Newtons reduces. This is due to the upthrust/resistance created by the water.

Next, Andreas dropped his ball of putty into the water.  It sank!  However, when he shaped the putty to have a larger, flatter bottom it floated.  How can this be?  The new shape of the putty had a greater surface area than the ball of putty. This greater surface area created more resistance/upthrust against the mass of the putty. This equaling of forces allows the putty to float.

We also made our own paper boats and carried out an experiment. This involved us putting our boat in water and learning how a boat in real life stays afloat instead of just sinking straight away. The lesson was very interesting and it was fascinating to find out how a boat stays up in water.










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