Build A Raft Cortesía de: Fort Worth Museum of Science and History
Experiment Category:
Objetivo:
Discover geometry by creating shapes from loops of paper.
Material necesario:
• 5 Craft Sticks
• 4 Twist Ties
• 4 Straws
• 1 Styrofoam cup
• Bag of Marbles
Qué debes hacer y en qué debes fijarte:
CHALLENGE: You need to build a raft to get across the river, so you want to make a small model to test your design. 1. Using 5 craft sticks, 4 twist ties, 4 straws, and 1 Styrofoam cup; build a raft that will support a Dixie cup with marbles in it. 2. When you have completed you structure, add the marbles one at a time until your structure is no longer afloat. How many marbles can your raft hold?3. Compare the design of your boat to that of the other students around you. Were there any differences? Any similarities?
Qué sucede:
This activity allows us to create structures that can float on water. Objects can float on water because of density and buoyancy. Density is the ratio of mass of a substance to its volume. Mass is the measurement of the amount of matter that something contains. The mass of an object is different than the weight of an object. The weight of an object can change depending on its location, but the mass will remain the same. Volume is the amount of space that an object takes up. Objects that float on water are referred to as being less dense, or lighter than water. Objects that sink in water are denser, or heavier than water.Buoyancy is the upward force that keeps things afloat. When placed in water, an object will float if its buoyancy is greater than its weight. And it will sink if its weight is greater than its buoyancy. You can increase the amount of buoyancy that an object has by increasing the surface area that the water is pushing against. Think about being in a pool. If you wrap your arms around your legs and curl up into a ball, what happens? (You’ll sink.) What if you stretch your body out flat? (You’ll float.)As students construct their rafts they use materials that are all less dense than water, which allows the raft to float. How they position the cup and the craft sticks will determine how many marbles their rafts will be able to hold.