Sink or FloatMaking and Testing Predictions

Which objects will sink or float in water?

1. Collect your equipment2. Choose at least 6 objects to test3. Make a prediction for each object4. Test each object and record results

Materials

• Containers of water for each table• Objects to sink or float

Ideas: button, crayon, paper clip, balloon, ping pong ball, rock, rubber band, plastic knife, egg, cotton ball, ice cube, apple, eraser, comb, plastic egg, candy bar, key, coin, small toys

Sample Data TableObject Prediction Trial 1 Trial 2 Was your prediction

correct?

floatsink

floatsink

floatsink

floatsink

Discussion Questions

• What kinds of reasons did you have for your predictions?

• Were all of your predictions correct?• Is it okay if some of your predictions were

incorrect?• What results were unexpected?• Based upon your results, can you make a

generalization about which things will sink or float in water?

SINKING SODA DEMONSTRATIONMaking and Testing Predictions

Sinking soda demonstration

Will cans of diet and regular cola sink or float in water?

Materials:• Large clear container • Water• Can of diet cola and of regular cola

Sinking Soda Demonstration

1. Write a prediction for Sinking Soda demonstration.2. Watch Sinking Soda teacher demonstration and

discuss the results.3. Watch Brain Pop Junior Video at 4. http://

www.brainpopjr.com/science/forces/sinkorfloat/grownups.weml#teachers

5. Write a journal entry about why you think your prediction was correct or incorrect.

SINK OR FLOAT PART 2More practice making and testing predictions

Make a Prediction

• What happens to the level of the water in the container when you place an object into the water?

Test the Prediction

• How can we use the materials we have here to test our prediction?

Test the class prediction

• How could we use the tools we have to measure exactly how much the water goes up?

• About how much will the level of the water go up if we drop a 1 cubic centimeter cube into water?

– Be sure there is enough water to cover the object– Be sure the object is completely under water before measuring

the change in the water

• What will happen if we submerge a 10 cubic centimeter stick? • A 100 cubic centimeter block?

Focus question: How much will the level of water go up in a graduated cylinder when objects are placed in water?

Procedure

1. Gather all of the materials that you need. 2. Fill your testing container with water. 3. As a class, determine the level that the water goes up for each of

the following: a 1 cubic centimeter, 10 cubic centimeter stick, 100 cubic centimeter large cube

4. Select at least three other items to test with your partner. 5. Decide which container will be best to test each of your objects.6. Predict about how much the water level will go up for each object. 7. Place each object in water and record the change in volume. 8. Choose another object and repeat. 9. Discuss class results

Important

• Be sure that each object is completely under water (submerged) before recording the amount the water level rises for each object.

• You can use the tip of a pencil to push the object completely under the water.

Sink or Float Part 2 Data Table

Object Volume of Object Prediction Trial 1 Trial 2 Was your prediction correct?

1 cm3 cube

10 cm3 stick

100 cm3 cube