HEAT SHIELD

The is our second trial design. Amalia and Anna made this which was a spherical piece of tin foil wrapped around the metal part of the stick. This design didn't work very well because the the tin foil was touching the metal, so when the metal got hot the hot glue melted. This picture was taken after the test, so the tin foil is a little bit burned.



This is our third design in its test. This on worked very well, withstanding the heat 3 minutes and 10 seconds, double that of the two previous trials. This design worked well because the tin foil and the mesh wasn't touching, and neither of those were touching the metal stick. This shield protected the glue without touching it rather than protecting it while touching it, causing the heat to spread.



This was the burning of my heat shield. It lasted 1 minute and 31 seconds before the hot glue melted and it fell off. This design didn't work very well because everything was touching the metal and/or the glue so the heat spread pretty quickly.



This was my design of a heat shield where I put everything in layers on the metal part of the stick. First the nut, the tin foil, the mesh, and then the washer. This design didn't work because all of the shield was touching the hot glue and not protecting the metal part of the stick, so the metal heated up and the heat spread quickly.


Today Anna, Amalia, and I designed a heat shield out of a 5" by 5" piece of mesh, a
5" by 5" piece of tin foil, a washer, and a nut that could withstand heat from a propane torch.

1st Trial: This was the one that I made. Everything was stacked on top of each other so it didn't work very well. It lasted 1:30 minutes.

2nd Trial: Anna and Amalia made this one. It also didn't work very well because everything was touching and there was only one layer of foil; they didn't fold it over. It lasted 1:35 minutes.

3rd Trial: We all made this one together. We decided that for the metal of the stick to stay cold, we would have to make it so the back-up piece of shield (the mesh) could be the only thing touching the hot glue/metal. We also decided that the tin foil couldn't be touching the mesh, otherwise when the foil got hot, it would spread quickly. So we made a cup shaped piece of foil and attached it with a little corner to the mesh. This design worked very well, and the hot glue melted after 3:10 minutes.

Relation to the Transformation of Energy:

There are 3 types of energy in this experiment:

Convection: The transfer of energy by the actual movement of warmed matter

Conduction: The transfer of energy through matter from particle to particle

Radiation: Electromagnetic waves that actually transport heat through space


The heat from the torch is primarily radiation. The radiated heat travels in waves through the air to the shield. Once the heat is at the shield, the energy is primarily conduction because the heat is moved particle to particle along the metal. To prevent damage, the shield has to absorb the heat and conduct it away from the sensitive structures behind it. Because of the first law of thermodynamics (energy can not be created or destroyed), after some time the shield is going to get really hot and probably burn up. When astronauts are coming through the atmosphere back to earth, their heat shields heats up so much that they glow red hot.

At first, we though that the heat shield was just to block the heat, not to conduct it away. That is the reason that our first designs didn't work; we had everything connected to the hot glue. We though that the tin foil would just block the heat, not conduct it. What happened in the first two trials was that the heat from the torch made the foil warm, which spread to the mes, which spread to the metal, which melted the hot glue because everything was connected. Our last trial worked because the tin foil conducted the heat away from the metal, while not touching the hot glue.