How do convection currents work in a hot air balloon?
The pilot heats the air in a hot air balloon. As the air gets hotter, it expands and its density drops. It will want to float above the more dense cool air and it rises up into the sky. This constant flow of air is a convection current.
What causes hot air rise convection?
Natural convection is caused by density differences. Hot air rises because it is less dense than cold air, so air will rise above a heater and sink near a cold window. Forced convection refers to fluids being pushed around by outside forces. Hot air rises, because it’s less dense than cold air.
How does convection heat cause a hot air balloon to stay in the air?
By heating the air inside the balloon with the burner, it becomes lighter than the cooler air on the outside. This causes the balloon to float upwards, as if it were in water.
Is ice melting an example of convection?
Yes, the melting of ice is an ideal example of convection. Ice melts since heat moves to the ice from the air.
What are the ways to transfer heat?
Heat can be transferred in three ways: by conduction, by convection, and by radiation.
- Conduction is the transfer of energy from one molecule to another by direct contact.
- Convection is the movement of heat by a fluid such as water or air.
- Radiation is the transfer of heat by electromagnetic waves.
What are the 3 types of heat?
Heat is transfered via solid material (conduction), liquids and gases (convection), and electromagnetical waves (radiation). Heat is usually transfered in a combination of these three types and seldomly occurs on its own.
What are the 4 methods of heat loss and give an example of each?
9 Cards in this Set
| Name 4 types of heat loss. | 1. Convection 2. Radiation 3. Evaporation 4. Conduction |
|---|---|
| Explain Radiation | Loss of heat from the body surface to a cooler solid surface not in direct contact, but in relative proximity. |
| Explain Evaporation | Loss of heat that occurs when a liquid is converted to a vapor. |
What happens to insulation when temperature rises?
With the increase in temperature, the conducting property of insulators increases. So when temperature reduces, insulation increases.
Does resistance depend on power?
Power in electronics is the rate of doing work. Resistance is the opposition offered against the flow of electrons. The relation between power and resistance is proportional.