Monday, 6 February 2017

Floating and Sinking First Class

We had some great fun experimenting with floating and sinking. We carried out a number of different experiments and we learned so much. 

First we explored floating and sinking informally. We tested materials around our classroom such as a rubber, pencil, pin. We predicted what we thought might float and what we thought would sink. After this we learned that whether something floats or sinks depends on a few factors; its shape, its weight and density. 

Our First investigation was designing and making a boat using Plasticine. We ensured it was a fair test for each group by measuring the amount of water in each container. We used a measuring jug and a litre container.  

Next we tested a ball of modelling clay in the water. We predicted that it would sink. We were right, it sank to the bottom. 

Then we modelled the Plasticine into a boat shape. We predicted that it would float. Some of our boats sank. We discussed why and came to the decision that perhaps some boats did not have enough air in them. We made them again and discovered that the boat  floats if it has enough air in the middle of the boat. 

We then added passengers to the boat using dried peas. We predicted that the boat would hold 30 peas before it sank. The result was very different to our prediction. The boat held 120 dried peas before it sank. This was really interesting and we had great fun counting too, we never thought it would take that many!!

Another experiment we investigated was dancing raisins. We placed raisins in still water and sparkling water. The raisins danced in the sparkling water and sank in the still water. This is because the bubbles cling to the raisins causing them to float to the top, then they lose the bubbles at the top and sink to the bottom, they continue to float and sink which makes it seem as though they are dancing!

We  also wrote up our experiment on designing and making a boat. 

We thought that learning about floating and sinking was so much fun that we decided to carry out a few more investigations in our groups....

Group 1: Sinking Orange. We learned that an orange floats with its skin on but sinks with the skin off. This is because there is air under the skin which makes it float. Really interesting!!

Group 2: Floating Fruit. We tested various fruits such as a lemon, lime, orange, blueberries and apple. The lemon and apple and orange floated due to the air under the skin of the lemon and orange and the air near the seeds of the apple. The lime eventually sank because there is not as much air under its skin.  The blueberries sank because they doe not have any air. 

Group 3: Floating egg. An egg will sink in plain still water however if you add salt to water the egg will float. 

We had so much fun investigating floating and sinking. We learned so much during our experiments We hope you try some of these experiments at home too! 

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