Why does something float or sink

But if that same steel is pounded and flattened thin and formed into a big bowl-like shape, the overall volume of the bowl is much greater than the volume of the steel cube.

The mass of the steel is the same but the big increase in volume makes the density of the bowl less than the density of water so the bowl floats. This is the same reason why a steel ship is able to float.

The material is shaped in such a way so that the density of the ship is less than the density of water. The American Chemical Society is dedicated to improving lives through Chemistry. Skip Navigation. Lesson 3. Engage Do a demonstration to show that the wax is heavier than the clay but that the wax floats and the clay sinks. Materials for the demonstration 1 tea light candle Clay Clear plastic container Water Large balance Teacher preparation Use a small enough piece of clay so that you are sure that the candle weighs more than the clay.

Procedure Place a piece of clay that weighs less than a tea light candle on one end of a balance. Remove the candle from its metal container and place the candle on the other end of the balance. Expected results Even though the candle weighs more than the clay, the candle floats and the clay sinks. Explore Have students compare the density of water, wax, and clay. Question to investigate Why does a heavier candle float and a lighter piece of clay sink?

Materials for each group 2 tea light candles in their metal containers Clay Water in cup Small balance Tape Dropper Procedure Compare the density of wax and water Roll two pieces of tape and stick them to the center of the pan at each end of the balance. Attach each tea light candle to the tape so that each candle is in the center of the pan. Use the wick to pull one candle out of its container. Expected results The water has a greater mass than an equal volume of wax.

Ask students: Which weighs more, wax or an equal volume of water? Water weighs more than an equal volume of wax. Which is more dense, wax or water? Water is more dense. Compare the density of clay and water Make sure you have one piece of tape in the center of each pan on the balance.

Fill one container with clay and place it on the tape so that it is in the center of the pan. For 6 Resources. Class practical: A group of blocks, all the same size but made from different materials, is used to introduce the concept of Practical Activity Demonstration: This method uses an equal-arm balance rather than a domestic spring balance.

Other resources on Density Density Properties of Matter. Density Properties of Matter. Demonstration: Showing that the mass of air in a bottle is small. Misconceptions Properties of Matter Some students think that heavy objects sink and light object float regardless of shape and size Number of Resources 0 Number of References 2 Number of Diagnostic Resources 2.

We've won an award! Babble Dabble Do has a fabulous ship building activity to demonstrate how displacement helps objects float. Can you make a superhero float? We made out superhero arm bands and a raft,. Rainy Day Mum has a lovely activity using boats made from pie tins.

Try a p irate themed sink and float investigation. Find out how many coins it takes to sink a foil boat. Learn about density with this easy investigation, can you find something to float on each layer? Instead of making an object less dense by adding bubble wrap, try changing the density of water to help an object float. Science Sparks Wild Sparks Enterprises Ltd are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources.

Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

Different objects float at different levels in the water because as most regular objects are lowered into the surface of water, the upward push of the water steadily increases until it is in balance with the weight force of the object, and the object then continues floating at this level with the two forces in balance.

Many objects that are hollow and so generally contain air float because the hollow sections increase the volume of the object and so the upwards push for very little increase in weight force down.

However, it is not necessary for an object to contain air in order to float. Explore the relationships between ideas about floating and sinking in the Concept Development Maps : Laws of Motion. Students will be familiar with the idea that objects have weight and that the size of the weight force is determined by the type of material and how much of it is used to make up the object.

Students should learn that when an object floats the water is pushing upwards on the object. For example, when you try to push a surfboard under the water you can feel the water pushing the board up.

Objects such as rocks that have sunk, are still experiencing an upwards push; it is just not as strong as the weight force. Students should be encouraged to view floating as being a result of the balance of the weight force on an object and the upward push of the water on the submerged part of the object.