«Task №3 » Curved mirrors Team «Isolenta» Prepared by Ilya Vasilev

Condition of the problem: Original condition Conduct and show interesting experiments in which large concave mirrors can be used to heat or cool various objects. Our condition Increase the temperature of the object using sun rays. Cool the object using the freeze rays system. Study dependence on diameter of mirrors.

Objectives Suggest ways of heating and cooling of objects using concave mirrors. Compare theory and practice.

How concave mirror acts? Principal optical axis R O F R/2 Parallel to principal optical axis rays are concentrated in the focus of mirror.

A method of heating an object The object is placed in the focus of the mirror Sun rays F Sun rays transfer energy. It concentrates on object in focus of mirror and the object heats up.

Photo of setup

The dependence of the received energy on the size of the mirror More rays fall on the larger mirror.

The dependence of the temperature on the diameter of the mirror T, oC t, s Diameter of the mirror is 6 cm Time is 60 sec Starting temperature is 27.91ºC Final temperature is 35.08ºC

The dependence of the temperature on the diameter of the mirror T, oC t, s Diameter of the mirror is 30 cm Time is 60 sec Starting temperature is 27.16ºC Final temperature is 77.67ºC

The method of cooling an object t1<t2 Ice t1 t2 Thermometer The red object has larger temperature than blue object. So red object radiates more infrared rays than blue object. The red object emits infrared rays, thus emitting energy and its temperature decreases.

The dependence of the temperature on the diameter of the mirror T, oC t, s Diameter of the mirror is 6 cm Time is 60 sec Starting temperature is 27.72ºC Final temperature is 25.05ºC

The dependence of the temperature on the diameter of the mirror T, oC t, s Diameter of the mirror is 30 cm Time is 60 sec Starting temperature is 27.16ºC Final temperature is 23.2ºC

Conclusion about experiments When diameter of mirror increases, the energy received by the object placed in focus increases also, because mirror with larger diameter gets larger number of rays, that transfer energy.

Conclusion We suggested ways of heating and cooling of an object . We focused sunlight on the object to heat it. We used ice for cooling . The temperature of object decreases, because the temperature of ice is lower, and object gives more energy.

Thanks for your attention!

Optical aberration