Unit E: Observing Objects

How can you tell one object from another?

1. Get Set to Explore


  • gas: Matter that flows and that changes size and shape to completely fill any container.
  • liquid: Matter that flows, has a set size, and takes the shape of its container.
  • matter: What things are made of.
  • object: A thing.
  • solid: Matter that has a set size and shape.

Building Background

  • Show children a group of small common items from the classroom. Tell children that each item is an object. Challenge children to give you another word for object. Guide children to realize that an object is a thing.
  • Demonstrate the differences between solids, liquids, and gases. You may wish to use a balloon that you blow up; a large, empty pitcher and a glass of water; and wooden blocks or other solid cubes of material. Elicit from children which items are solid, which holds a liquid, and which encloses a gas. Then go over the definitions of solid, liquid, and gas with the class. Show children how the liquid (the water) changes shape but not size when you pour the water from the glass into the large pitcher. Show children how the gas (the air in the balloon) changes both shape and size when you release the gas from the balloon. (The air that is inside the balloon, once released, will spread throughout the entire classroom.) Point out that one thing children might notice or observe about an object is whether it is formed of a solid, a liquid, or a gas.
  • Explain that the computer activity they will be doing involves sorting objects in different ways. You might demonstrate a simple sorting process using coins. Work together with children to sort a group of coins by size. Then re-sort the coins by color. You might sort the coins a third time by shininess.
  • Help children come up with a functional definition for sorting: putting objects in different groups based on a specific feature. Let children list some features they could use to sort objects. Read the Discover! question to the class. Point out that the answer has to do with sorting.

2. Guide the Exploration

  • Direct children to launch the Discover! Simulation. Tell them that they will need to follow the directions for sorting the objects.
  • If necessary, show children how to use the cursor to drag an item from the center of the screen and drop it into one of the bins. Explain that if they sort items incorrectly, they will get another chance to put the item in a different bin.
  • Encourage children to play all three of the sorting games presented in this simulation.

3. Review/Assess

  • After children have completed the simulation, ask: How did you sort the items in the first game? Volunteers should note that the sorting was by color. Let children share how the objects were sorted in the second game (by shape) and the third game (by composition, i.e. state of matter—solid, liquid, or gas).
  • Use Step 3's Wrap-up text to summarize the sorting process.
  • Present the Extension question to the class. Provide a variety of safe, everyday objects for children to choose from. Guide children to realize that in addition to color, shape, and composition, they can also sort objects by size, weight, length, width, height, material, whether the object is magnetic, function, and many other features.

If time permits, present children with the following questions:

  • Critical Thinking Analyze When you sorted the objects on the computer, you relied on your sense of sight. Imagine you were cleaning out your refrigerator. What senses would you use to pick out the food that had spoiled? Answer: Children should mention sight, smell and perhaps touch; point out that the sense of taste should not be used because tasting spoiled food can be dangerous.
  • Inquiry Skill Compare Review the definition of solids, liquids, and gases. Based on the definitions, how are liquids and gases similar to each other? How are solids and liquids similar to each other? Answer: Liquids and gases both flow and change shape to fit their containers; solids and liquids both always keep their own size.

4. Reaching All Learners

On Level: Kinesthetic Learners

Give children a set of objects that they can sort by texture. You might include fabrics of different types, different types of paper and cardboard, rug samples, and such. Let children work in pairs to sort the materials. Remind them to use texture to do their sorting. When they are finished, have them show you their piles and explain how they sorted the items. Allow them to explain to other children how they sorted the materials. Guide the class to realize that for this activity, the sorting was done mainly by touch. Explain that with the computer activity, sorting was or will be done by sight.