Science, Physical Science

Grade 3- 5

Objective

Students observe how substances are held together by bonds.

Directions

Tell students that chemicals are substances held together by bonds. Some bonds are stronger than others. Two types of bonds are covalent bonds (bonds formed by the sharing of electrons) and ionic bonds (bonds formed by the attraction of oppositely charged ions). This activity provides students with the experience of observing and stretching bonds. They will actually see how substances are held together.
Student Directions:

1. Hold the sheet of newspaper so that it looks as if you are holding a rectangle. With your hands, pull (in opposite directions) both ends of the paper. Note what happens.
2. Rip the sheet of newspaper in half. Note how easily it rips and the shape formed on each piece of paper after it is ripped.
3. Repeat steps 1 and 2 with each type of paper.
4. Carefully and slowly stretch a marshmallow to the point where it is ready to separate into two pieces.
5. Using the standard (metric) ruler, measure to the nearest inch (centimeter) the farthest distance that the bonds in the marshmallows stretched. Record your observation.
6. Repeat steps 4 and 5 with a piece of gummy candy and with a piece of candy containing chewy caramel.
7. Complete your data-capture sheet.

Resources

• For Each Group: one sheet each of newspaper, typing paper, construction paper, writing paper, and cardboard.
• gummy candy
• candy containing chewy caramel
• marshmallow
• standard (metric) ruler
• Bonds data-capture sheet (one per student)