Radiant Heat

Outcomes Met so far & what’s next 308-1 112-9 308-2 308-3/4 308-5 UPCOMING 308-6 308-7 112-1

Radiant Heat Demo Question: Does the color of paper affect how an object reacts to radiant heat? Hypothesis: If color affects how objects react to radiant heat, then the ______________ beaker will ___________.

Demo 1. Fully cover the outside of a beaker with black construction paper. 2. Fully cover the outside of another beaker with white construction paper. 3. Cover third beaker with aluminum foil 4. Fill all three beakers equally with room temperature water. 5. Record the temperature of the water for each beaker. 6. Place the beakers in the same location, exposing them to the heat lamp. 7. Predict what will happen to the temperature of the water in each of the beakers. 8. Record your predictions in your notebook. 9. Take the temperature of the three beakers: 10 trials at two minute intervals. Record the temperatures in the provided table in your notebooks

All kinds of radiant energy interact with matter: Radiant Energy waves can be absorbed and reflected by objects. • Absorption: occurs if the energy penetrates part way into the object. Dull dark objects absorb radiant energy when they are cool, and emit radiant energy when they are hot. (eg. asphalt sidewalk) • Reflection occurs if the energy cannot penetrate the surface of the material it comes into contact with. Light, shiny objects or surfaces do not absorb radiant energy readily and do not emit radiant energy readily. (eq. ice surface) • Transmission: occurs if the energy penetrates completely, passing through the object with no absorption of energy.

Solar Energy Radiant energy from the sun is referred to as SOLAR ENERGY The most important form of radiant energy- it sustains life on earth, but less than 1% of earth’s power comes from solar energy (2009)

Solar Energy Greenhouse Effect: Some of the sun's energy that reaches Earth is transformed from light to heat. The atmosphere traps the heat and keeps our planet warm. This is called the Greenhouse Effect. Photosynthesis: Plants turn sunlight into sugars. This provides energy for the plants to grow. Plants store the sugars in their leaves, stems, fruits, and roots.

Solar Energy- Technology Solar panels are designed to specifically transform solar energy into electrical energy Solar panels have a collection of plates that have a transparent covering with dark metal plates beneath which absorbs heat. The sun’s thermal energy is reflected and focused on a large water boiler often on a tower. The fluid boils to produce steam which drives a turbine to generate electricity.

Photovoltaic Cells Small solar panels that use solar energy and convert it directly into electricity (ex: in your calculators) Semiconductor materials absorb sunlight energy and create an unbalanced flow of electrons from one side of the solar cell to the other. The sides are connected with a metal material which allows the electrons to travel. The flow of electrons produces electricity.

Radiant Heat Demo Construct a line graph whose horizontal axis (x-axis) records the exposure time to radiant source and whose vertical axis (y-axis) records the internal temperature of the beaker. Plot and compare. Analyse and share the results of your findings. Which bottle registered the highest internal temperature? Lowest temperature? Explain the process of radiation as it applied to this investigation.