Tag Archives: floating and sinking

Floating and Sinking; What is the best material for a life jacket?

We had great fun this week in Senior Infants in room 2. We wanted to find a good material to use in life jackets so we started by investigating different materials to see if they would float or sink when placed in water. Before we tested the materials, as a class we chose eleven different materials to test. We predicted what we thought would happen to each material. There were 19 people in the class at the time and we counted how many people thought that the object would float or sink and recorded the results in the table below. pic

We tested the materials by placing the object in a basin of water and watched to see if it floated or sank. We recorded the results in a table.

pic2From this experiment we learned that if an object is lighter than water it will float and if an object is heavier than water it will sink.

Having identified different materials that floated, we investigated what material would be good to use for to make life jacket. We discussed how to stay afloat in the water and what things help us to float in water. We made six people using plasticine and when we placed them in water each of them sank to the bottom. We chose 6 different materials (felt material, bubble wrap, inflated balloon, cotton wool, polystyrene and cork) and compared their weights and classified them as heavy or light. Each of the plasticine people was attached to a material. They were placed in the water and we observed which of the materials worked best to keep the person afloat. We made a list of the materials in order of which would work best for a life jacket.

1. Polystyrene

2. Balloon

3. Cork

4. Bubblewrap

5. Felt material

6. Cotton wool

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