We normally think white has no color and that black is made of every color, but what if I told you it was the opposite? Because an object absorbs different wavelengths of light depending on its color, we can test this idea using the properties of heat! In this experiment, we’ll see how different colors of paper warm up in the sun, and we’ll also learn how light gives objects color.

MATERIALS:

Colored paper (4 black, 4 white, 4 red, and 4 yellow)
Scissors
Tape
4 ice cubes
Warm, sunny day
Optional: Infrared thermometer

TIME ESTIMATED:

20 minutes

DIRECTIONS:

Using the same colored paper, cut and tape the 4 pieces to make a box with an open top.
Repeat this for each color.
Put each box outside so the sun hits them. Be sure to place them all on the same surface, like concrete!
Next, grab your ice cubes and place one inside each box. Keep track of which color’s ice melts first, second, and so on.
Optional: You can also leave a sheet of each color in the sun, then take the temperatures with the thermometer. Compare the results.

Think LIke a Scientist!

Why do the boxes' colors change the speed the ice melts at?
Why did we put all of the boxes on the same surface?

HOW DOES IT WORK?

To understand the science behind this, let’s first explore color. When we look at an object, we’re actually seeing the light that’s bouncing off of it. Light is made of waves moving through space, and different colors happen when only part of the wave bounces back. Believe it or not, things appear white because they reflect back all of the light that we can see. This means white is made of every color! We see black when all of the visible light gets absorbed (or stuck inside) the material, so none gets reflected back to our eyes. Because light is a wave, we measure it using its wavelength, or the length between its peaks. All the other colors reflect light with their own specific wavelength, and together they make the visible light spectrum.

In the real world, when we see a color, we see a mixture of many different wavelengths (or colors). You can also mix colors to make new ones and create different shades of the same color. The amount of light (or heat) our red and yellow boxes absorb depends on the brightness of their color. Yellow is usually brighter than red because it reflects many different wavelengths, so the ice inside the yellow box likely melted for it first. The surface below the boxes also changed their temperature, which is why we made sure to put them on the same material. If we placed some on grass and others on concrete, we wouldn’t have accurate results.

Further exploration:

Electronic engineers create all sorts of technology, ranging from GPS systems to lasers. They also design the devices we use to watch our favorite shows, and everytime we turn on the screen, we’re relying on the science of visible light! In order to produce all the different images, display screens use only three colors of light: red, green and blue. To make all others, they mix these together, using a different amount for each color. With just these, engineers design TV’s and computers that have a seemingly endless supply of colors, making any shade from three simple building blocks.

Anticipated concerns

Be careful handling the scissors.

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