8th Grade Science Focus on Acheivement Week 5

Gamma rays have the shortest wavelength of the electromagnetic waves. Which of the following is also true of gamma rays?

• They have the highest energy.

• They are visible to humans.

• They have the lowest frequency.

• They are only emitted by the Sun.

Answer explanation

The shorter the wave is, the more energy it will carry. Think about the mouse keeping up with the giraffe!

Visible light and ultraviolet (UV) light are both forms of electromagnetic radiation, and waves of each travel at the same speed. Human eyes are unable to see UV light because it is not in the visible range of the electromagnetic spectrum. If the frequency of one UV light wave is twice that of a visible light wave, how will their wavelengths compare?

• The wavelength of the UV light wave will be half that of the visible light wave.

• The wavelength of the UV light wave will be twice that of the visible light wave.

• The wavelength of the UV light wave will be four times that of the visible light wave

• A.The wavelength of the UV light wave will be the same as that of the visible light wave.

Answer explanation

I bet if you thought about this for a minute, you'd have figured it out.

Waves that go by twice as fast as other waves (frequency) will be half the size!

Think about the mouse and giraffe waves!

Francesca is drawing a picture of the electromagnetic spectrum. She needs to order the types of electromagnetic radiation from the lowest to highest frequency. Which of the following shows the correct order of the electromagnetic spectrum, from lowest to highest frequency?

• visible, UV, infrared, X-ray, microwave, radio, gamma

• radio, visible, microwave, infrared, UV, X-ray, gamma

• gamma, UV, microwave, infrared, radio, X-ray, visible

• radio, microwave, infrared, visible, UV, X-ray, gamma

Answer explanation

What?!? Have you already forgotten about:

Raging Monsters Invading Venus Using X-ray Guns?!?!

While Paul is swimming at the pool, he uses the ladder to get out of the water. When he looks down at the water, he notices that the ladder appears bent at the point where it enters the water. This phenomenon is a result of which of the following?

• Conduction

• Diffraction

• Reflection

• Refraction

Answer explanation

Refraction sounds similar to the word fracture. Like a bone breaking.

When light bends it REFRACTS and makes the image look bent or broken

Tonya shines a flashlight at a mirror. Which of the following best describes what will happen to the beam of light?

• A.It will hit the mirror and change direction.

• A.It will bend as it passes through the mirror.

• A.It will bounce back directly toward the flashlight.

• A.It will stop at the mirror as the light waves are absorbed.

Answer explanation

Because the light doesn't go through the mirror, it hits the surface and bounces right back at the same angle it hit the mirror with.

Reflection!

Carmen has a clear glass plate and a solid plastic white plate. She holds both plates up to the Sun. The plastic plate makes a shadow on the ground, but the glass plate does not. Which of the following correctly compares what happens with each type of plate?

• The plastic absorbs light; the glass reflects light.

• The plastic bends the light around it; the glass absorbs light.

• The plastic reflects light; the glass allows light to bend around it.

• The plastic reflects light; the glass allows it to pass straight through

Answer explanation

The white plate reflects light. The glass plate lets it be transmitted.

FYI: LIGHT Waves DO NOT BEND around objects!

They reflect, refract, transmit or absorb. That's it!

Warren is tuning his guitar. He notices that as he tightens the string, the pitch of the string increases. Which best explains why tightening the string raises the pitch?

• It makes the string more flexible.

• It improves the string's ability to make sounds.

• It increases the frequency of the string's vibration.

• It allows sound waves to move along the string more easily.

Answer explanation

Sound waves are light light.

Tightening the string shortens the waves the string makes.

Shorter strings vibrate with higher frequency.

Higher frequency will sound liker a higher pitch

Arianna is experimenting with different materials to see how they transmit sound. Through which of the following materials will sound waves travel the slowest?

• Air

• Water

• Concrete

• Motor Oil

Answer explanation

Since sound requires particles to touch in order to transmit the vibration...the closer the particles are, the faster the sound travels!

This typical hand-held magnifying glass has made the words appear much larger. Which property of light allows the magnifying glass to work?

• Light is being refracted

• Light is being reflected

• Light is being absorbed

• Light is being transmitted

Amber likes riding her bicycle through her neighborhood where there are lots of hills. She rides down a very steep hill, and then goes up a small hill. She doesn't need to pedal as her bicycle carries her up the small hill. How do Amber's kinetic energy and potential energy change as she goes uphill?

• Her kinetic energy and her potential energy both increase.

• Her kinetic energy and her potential energy both decrease

• Her kinetic energy increases and her potential energy decreases.

• Her kinetic energy decreases and her potential energy increases.

Answer explanation

Kinetic and potential energy are constantly transformed from one to another and an object stops and starts.