Daily Science pg. 54 1. Grab the National geographic article we read in class last time. Finish your paragraphs. If you are finished, make sure you have.

Daily Science pg. 54Grab the National geographic article we read in class last time. Finish your paragraphs. If you are finished, make sure you have included 5 vocabulary words and have highlighted or circled them.

Next, I want you to write a paragraph on whether or not you believe the experiment the scientists did was ethical. Support your reason. Suggest one thing the scientists could have changed to better their experiment.

The Earpg. 54

LightPg. 55

Behavior of LightLight acts as both a wave and a particle.When passed through slits, light waves were seen to act like a wave by producing interference patterns.

Light as a waveThe wave model describes light as transverse waves.They are called electromagnetic because they consist of changing electric and magnetic fields.Model also explains why light reflects, refracts, and diffracts.

Light as a stream of particlesScientists performed experiments and saw that light acted like energy contained in small packets.The particle model of light refers to the packets of energy as photons.Photons do not have mass.Energy in a photon is located in a specific area.

Energy of lightThe energy of light is proportional to the frequency.The lower the frequency, the less energy contained in the light.Ex.: red light contains 3.0 x 10-19 J of energy and has a frequency of 4.5 x 1014 Hz. Ultraviolet light has twice as much energy, therefore the frequency of UV light is twice as much as red light.

Speed of LightIn a vacuum: 3.0 x 108 m/sIn air: 2.997047 x 108 m/sIn ice 2.29 x 108 m/sIn diamond: 1.24 x 108 m/s

Brightness of lightIntensity determines the brightness.In light, intensity is the number of photons per second that pass through a certain area.Intensity decreases as you move away from a source.

The Electromagnetic SpectrumConsists of waves at all possible energiesRadio waves are the lowest frequencies.Radar is a system that uses radio waves to find the location of objectsMicrowaves are next on the spectrumInfrared light is slightly bigger than visible light.Can be felt as warmthThen there is visible light.Ultraviolet light has a frequency greater than visible light.X-rays and gamma rays have the highest frequencies.

Electromagnetic spectrum

Ultraviolet lightComes from the sunThe Ozone protects us from itCan cause sun burns

X-rays and Gamma RaysX-rays have such a high frequency that they can pass through tissues and bones.Gamma rays have the highest energy and can be used to treat cancer.