In this section we will look at the forces of different strengths.

Think again about a picnic. The breeze blew napkins around and tipped plates. What would happen if the breeze turned into a strong wind? What about if a tornado blew through? Obviously, stronger winds would move heavier things.

Try It!

Materials:

• Fan
• Popped popcorn
• Meter or yardstick

Procedure:

1. Put a popcorn kernel on a table or the floor.
2. Lean over 1 foot from the popcorn.
3. Blow gently. Record how far the popcorn moves.
4. Put the popcorn back to where you started. This time blow hard. Record how far the popcorn moves.
5. Put the popcorn back. This time, position the fan 1 foot from the popcorn. Turn the fan on low. Measure how far the popcorn moves. You may need to use the yardstick more than once, and add the distances together.
6. Put the popcorn back one last time. This time start the fan on high. Measure how far the popcorn travels.
7. Write a paragraph about how stronger forces move things farther. You may want to add drawings to show your observations.

 Distance Traveled Observations Blowing Gently Blowing Hard Fan on Low Fan on High

Remember the story of The Three Little Pigs? The wolf blew down the straw house easily. He had to try harder, or use more force, to blow down the house of sticks. He huffed and puffed, and huffed and puffed on the stone house, but couldn’t create enough force to blow it down.

Just for Fun

Rewrite the story of The Three Little Pigs. You could change the forces the wolf uses to blow down the pig's houses. You could change the materials the pigs used to build with, or you could change the point of view of the story.

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