Activity 1: Explore (30-40 minutes)

1. Distribute the Detective’s Logbook student handout to each student. Explain that, just like real detectives, they must use inquiry and observation to learn as much as they can about what is unique and special about eggs.
2. Review question 1: What’s inside of me? Ask students how they might learn what’s inside of an egg. If they don’t suggest cracking one open, guide them in that direction. Then conduct the following demonstration:
   1. Crack a raw egg into a bowl, and let the students observe what’s inside.
   2. Ask the students to describe to a partner what they see.
   3. Direct the students to draw and label each of the following egg parts in their Detective’s Logbook:
      • Shell- Protects and covers the egg. Made of calcium carbonate.
      • Yolk- Yellow center. Produces food for the embryo. Major source of vitamins and nutrients.
      • Albumen- Clear white liquid around the yolk. Protects the yolk and provides additional nutrition.
3. Review question 2: Are all of my egg friends the same size? Ask students how they might learn the answer to this question. One way to compare egg sizes is to measure them. Hold up an egg and ask students to name all of the different ways they could measure it. Ideas include measuring length, width, and even weight. For each measurable attribute, ask student volunteers for ideas of objects they could use as a measuring tool. For example, they could measure an egg with a ruler, their finger, a piece of string, or even a set of blocks. Once students have given several ideas for ways to measure the egg, follow the steps below:
   1. In their groups, ask students to pick out three or four eggs that appear to be the same size.
   2. Demonstrate how to use string to measure the eggs vertically and horizontally. Put a ruler down on the table or desktop. Use a piece of string to go around the middle or horizontal area of an egg. Put a felt-tip mark on the end of string that matches up with the beginning of it. Then, put the string along the edge of the ruler and see how long it is. Write down this measurement by “Egg 1” on the handout.
   3. Show them how to measure the egg vertically, mark and measure. Record the measurement on the handout.
   4. Have the students do the same thing with the rest of the eggs, keeping measurements and observations in their Detective’s Logbook.
   5. Direct students to use the scale to weigh each egg and record the weight in the Logbook. Note: To prevent eggs from rolling off of the scale, you may want to weigh a cup and then have students weigh the eggs inside of the cup.
4. Review question 3: Does my shell have any holes in it? Ask students how they might learn the answer to this question. Then, conduct the demonstration below.
   1. Place the egg carefully into the glass or jar.
   2. Carefully pour hot water into the glass or jar until it is nearly full.
   3. Leave the glass or jar on a table or flat surface and watch the egg closely for a few minutes (the glass may become hot so be careful).
   4. Direct students to record or draw their observations in the Logbook.
      • Note: After surrounding the egg with hot water, they should observe tiny bubbles forming on the egg shell which eventually bubble their way to the surface. Explain to students that an egg contains a small air pocket at its larger end between the shell and egg white. When the air trapped inside this small pocket begins to heat up it expands and tries to find a way out of the shell. Ask students how they think the air escapes.
   5. Let students take turns using a magnifying glass to examine the egg. See if they can identify small pores on the shell. Direct students to add to their observations.
5. Review question 4: What would happen if I swam in vinegar? Ask students how they might find out the answer to this question. Guide them toward understanding that they could dip an egg in vinegar. Then, conduct the following demonstration. Explain to students that this demonstration may take one to two days to complete.
   1. Place a raw egg in a jar, add enough vinegar to the jar to cover the egg, and replace the jar lid. Ask students what they see and have them record their observations in their Detective’s Logbook. The shell is covered with tiny bubbles of carbon dioxide, some rising to the surface. Ask students to look at the jar after 36 to 48 hours and add to their observations. They will likely notice that the shell has dissolved.
   2. What does this demonstration tell them about the properties of eggs?

Activity 2: Explain (20 minutes)

1. Divide students back into their four groups, and direct each group to stand by a different sign/egg from the beginning of the activity.
2. Ask the group to discuss among themselves what they learned from the demonstration and their observations about the unique properties of eggs.
3. Have each group explain what they learned to the rest of the class. Allow students to ask questions or add to each other’s explanations.