The rate of heat flow between two objects is proportional to their difference in temperature. One experiences this every day, with stoves, outdoor weather and touching things. If you touch something that’s the same temperature as your hand, there’s no heat flow at all. This model allows you to adjust the temperature difference between two […]
Heat flows through solids at rates measured by their conductivity. The rate of heat flow is also proportional to the thickness of the material. This model compares the rate of heat transfer between two objects when they are separated by walls of different thickness.
If there are air leaks in a house, you might expect that their effect would be magnified on a windy day. The wind creates greater air pressure on the windward side of the building and forces air in through the leaks. At the same time, the pressure on the other side of the building is […]
Convection refers to transfer of heat by a fluid material (such as air or water) moving from one place to another. The convection is forced if the fluid motion is caused by a fan or a pump while natural convection is the result of density differences.
Conduction of heat refers to the transfer of heat through a solid. Convection refers to the transfer of heat by a fluid material (such as air or water) moving from one place to another. Warm air is less dense than cold air, so it rises and cold air sinks. This is called natural convection. Air […]
The convection of heat in air happens naturally because warmer air is less dense and rises, causing air circulation in many situations. But not always! Air can stratify, with warmer air up high and cooler air down low. With this model you can explore how convection works if the heat source is near the ceiling […]
Air circulates quickly and easily if there are temperature differences to drive its motion. This may be desirable in a room, but in insulated walls and ceilings air circulation is a problem, since it transfers heat. Explore the effect of multiple barriers on the amount of convection and apply this to how insulation should be […]
Most buildings have leaky places where air can enter or escape — around windows, ceiling openings like pipes, wires or chimneys, and construction joints such as where the wall meets the floor or the floor rests on the foundation. The size and location of these leaks strongly affects the heating and cooling load. Use this […]
This activity helps students understand dilations of functions, where a dilation is a vertical or horizontal stretch or compression. When a function is multiplied by a number, the shape of the graph will retain its basic shape, though stretch or compress in different directions. By the end of the activity students will be able to […]
A reflection is a transformation of the graph of a function over the x-axis or the y-axis (or both). The function retains its basic shape; however, by including a negative sign in the appropriate place in the equation, the graph of the function will flip over one or the other of the axes. By the […]