A red laser is aimed at a flat mirror in a dark room. A bright spot appears on the far wall, the mirror stays cool, and nothing is seen behind it. What happened to the light?

At noon a black asphalt playground reaches 55 degrees Celsius. No light passes through the asphalt, and the dull surface produces no glare. What happened to most of the sunlight?

Sunlight strikes a clean window pane. The floor inside is brightly lit, the glass itself barely warms, and no bright glare is seen from outside. What happened to most of the light?

A hiker shouts toward a rock cliff about 340 meters away and hears his own voice again roughly 2 seconds later. What did the cliff do to the sound waves?

A heavy dark curtain is pulled across a sunny window. The room goes dark, the curtain shows no bright glare, and the fabric feels hot to the touch. What happened to the sunlight?

A portable radio inside a closed wooden shed still plays a distant station clearly. This shows that the wooden walls transmit radio waves.

On a chest X-ray image the film behind the patient's soft tissue is dark, while the film behind the ribs stays light. What did the soft tissue do to the X-rays?

A student shouts in a room with thick carpet, heavy curtains and cushioned sofas. No echo comes back, and a listener in the next room hears nothing. What happened to the sound energy?

A survey boat sends a sound pulse straight down into the ocean and detects the same pulse arriving back at the boat 4 seconds later. What did the seafloor do to the sound wave?

Under classroom lights, students in every seat see a white wall equally well. The wall stays cool, and no light reaches the corridor behind it. What happened to the light at the wall?

A person sits under an infrared heat lamp. Her skin feels warm within seconds, and a detector placed behind her arm reads no infrared at all. What did her skin do to the infrared waves?

In bright sun a snowfield stays near 0 degrees Celsius and is painfully bright, while dark soil beside it reaches 20 degrees Celsius. What happened to most of the light at the snow?

Thick porous foam panels absorb far more sound energy than polished ceramic tile, so foam is the better wall covering when a music room must stop echoes.

An engineer needs the metal plate inside a solar water heater to turn as much sunlight as possible into thermal energy. Which surface finish should the plate be given?

A rescue team needs a light sheet that sends a cold runner's own body heat back toward her instead of letting it escape into the night air. Which sheet meets that requirement?

A satellite dish must gather weak radio waves from the sky and send them all to a receiver at one point. Which dish surface best meets that requirement?

A dental patient needs a covering that stops X-rays from reaching the rest of her body while her mouth is imaged. Which covering best meets that requirement?

A greenhouse roof must deliver sunlight to the plants below while keeping wind and rain out of the building. Which roofing material best meets both requirements?

A cyclist wants a driver's headlights to send light straight back toward that driver at night. Which material on her vest best meets that requirement?

A hiker needs lenses that cut how much visible light reaches her eyes and also stop ultraviolet from getting through to them. Which lens best meets both requirements?

A classroom facing the afternoon sun gets too hot, but the teacher still wants daylight in the room. Which window film best meets both requirements?

A hospital wants the wall between two consulting rooms to keep speech from passing through to the next room. Which wall build best meets that requirement?

A red plastic filter over a flashlight lets a red beam out but no green light. Why does the one sheet of plastic treat the two colors so differently?

Sunlight reaching the ground is bright, yet most ultraviolet from the Sun never arrives at the surface. Why does the atmosphere treat visible light and ultraviolet so differently?

A microwave oven heats a mug of water in seconds, but a bright flashlight shone on the same mug for minutes barely warms it. Why does water treat the two waves differently?

A hand completely blocks the light from a lamp, yet X-rays from a machine pass through the same hand to reach a detector. Why does the hand treat the two waves differently?

On a heavily overcast day sunlight is blocked, yet a satellite television signal still reaches the dish on the roof. Why do the clouds treat these two waves differently?

A closed wooden door blocks the light from a bright hallway, yet a conversation outside can still be heard through it. Why does the door treat light and sound differently?

Radio telescopes work from mountain tops on the ground, but X-ray telescopes must be placed in orbit. Why does Earth's atmosphere treat these two waves differently?

Because a window pane transmits visible light, it must also transmit the ultraviolet and infrared waves that strike it.

The table shows what happens to sunlight energy at four roof coatings. Which coating keeps the roof surface coolest in strong sunlight?

The table shows what happens to light energy at four greenhouse roof panels. Which panel delivers the most light energy to the plants growing below it?

The table shows what happens to sound energy at four studio wall panels. Which panel reduces echoes inside the studio best?

A blind fabric reflects 20 percent of the light energy striking it and absorbs 55 percent. What percent of the light energy is transmitted through the fabric?

A material is tested with light and returns 80 percent of the energy, absorbs 15 percent and transmits 5 percent. Which everyday object behaves most like this material?

The table shows what happens to ultraviolet energy at four sunscreen lotions spread on test plates. Which lotion lets the least ultraviolet reach the skin below?

A sample that reflects 90 percent of the sunlight striking it will warm up more in the Sun than a sample that absorbs 90 percent of the same sunlight.

The table shows what happens to light energy at four test samples. Which sample sends back about as much light as it lets through, while absorbing very little?

A plastic panel reflects 15 percent and transmits 60 percent of the 200 units of light energy shone on it. How many units of energy does the panel absorb?

The table shows what happens to light energy at four sunglass lenses. Which lens lets the least light reach the eye while the lens itself stays coolest in bright sun?