3.1 – 3.2 Properties of Electromagnetic Radiation

Answer the questions below! Mini Activity 1. Find a light source where you are (ex: ceiling lights, phone flashlight) 2. Using that source of light, make a shadow with your hand 3. Draw a sketch of what you see. Make sure to include: Light source Hand Shadow 4. Draw arrows from the light source to represent travelling light. Label these “light ray” Answer the questions below!

Mini Activity Flashlight at 5 cm Flashlight at 30 cm Flashlight at 1 m How bright is the light on the wall? Find a flashlight and shine it on a wall 5 cm away. Observe and record Slowly move away from the wall. Observe and record Move away even further. Observe and record

What forms of INVISIBLE energy can you think of? Light behaves as a wave Light is a form of energy that is visible to us There are many forms of invisible energy in the world as well What forms of INVISIBLE energy can you think of? Make a list on the board of their responses

Microwaves heat your food, but you cannot see the microwaves being absorbed by your food Somehow your phone receives wifi, but you cannot see this wifi travelling through the air UV rays and X rays can damage your body, but you cannot see them doing the damage Infra red waves travel from your remote to your TV, but you cannot see anything between your remote and the TV

Electromagnetic Spectrum The collection of these invisible and visible energies is called the electromagnetic spectrum

https://www. pbslearningmedia. org/resource/phy03. sci. phys. mfw https://www.pbslearningmedia.org/resource/phy03.sci.phys.mfw.spectrum/tour-the-electromagnetic-spectrum/#.Wtd55YjwbIU Run through this interactive with the class all together

Electromagnetic Spectrum Breakdown Electromagnetic Wave What are they used for? Radiowaves Transmit radio and television programs

Electromagnetic Wave What are they used for? microwaves Heat food, transmit signals such as cell phones or satellites

Electromagnetic Wave What are they used for? infrared Computer date and telephone calls through optical fibers, TV remotes, thermal imaging

Electromagnetic Wave What are they used for? Visible light Vision, photography

Electromagnetic Wave What are they used for? Ultraviolet Fluorescent lamps, security, disinfecting water

Electromagnetic Wave What are they used for? X-rays Medical x-rays, airport security scanners

Electromagnetic Wave What are they used for? Gamma rays Sterilizing food and medical equipment, detection of cancer and treatment

Look it up! Research the different parts of a wave and fill in your notes with what you find Fill in what they find with a pen on the board using the image provided

Light Travels in Waves Crest = top of the wave Trough = bottom of the wave Amplitude = height from rest to crest or trough Wavelength = distance from crest to crest or trough to trough

Proof that Light Travels in Waves Thomas Young demonstrated that light behaves as a wave in the 1800’s. He conducted the double slit experiment. In your notes, predict what the light will look like on the second screen by drawing it. Watch this after prediction: https://www.youtube.com/watch?v=Iuv6hY6zsd0&t=357s Have them complete what ACTUALLY happens Watch this!

MINI ACTIVITY!!! In groups of three complete the mini activity in your notes on waves

Research Which colour from the visible light spectrum has the longest wavelength? Which colour has the shortest wavelength? Make sure to fill in the wavelength with the matching colour

Light, is it a wave or a particle?