# Plants Help Keep a House Cool!

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#### Updated on Feb 11, 2009

Using shade trees to keep a house cool!

### What do you need?

1. Two shoe boxes or small cardboard boxes
2. A reflector lamp with a one-hundred watt incandescent light bulb in it (you can also use the sun instead of a lamp)
3. Various types of plants in pots - small bonsai trees would work OK if you have one -- ask your folks first before using any of their plants.
4. Two good thermometers to measure air temperature. If you have a digital thermometer that measures inside temperature with an external sensor to measure outside temperature, that would work great!
5. Small can of black or dark-color paint and small can of white paint

### What do do?

This experiment is done in three steps. First you'll want to see if shading your "house" will keep it cooler. Then you'll want to see if painting the "house" different colors outside affects the temperature inside. Third you can combine the colored houses with or without shading.

#### Step 1

1. Take both boxes and place them an equal distance from the lamp so that both of them get the same amount of light hitting them.
2. Put the thermometers inside the boxes.
3. Place plants between the lamp and one of the boxes so that the shadows cast by the plants cover most of the entire "house."
4. Turn on the lamp.
5. Measure the air temperature in each over a period of time. Which box has a higher temperature? Does the temperature change? Subtract or add plants?do the number of plants change the temperature of the shaded "house?"

#### Step 2

1. Paint one of the boxes white and the other box black
2. Put both boxes and place them an equal distance from the lamp so that both of them get the same amount of light hitting them.
3. Put the thermometers inside the boxes.
4. Turn on the lamp.
5. Measure the air temperature in each over a period of time. Which box has a higher temperature? Does the temperature change?

#### Step 3

1. Place plants between the lamp and one of the boxes so that the shadows cast by the plants cover most of the entire "house."
2. Turn on the lamp.
3. Measure the air temperature in each over a period of time. Which box has a higher temperature? Does the temperature change? Subtract or add plants or change the house they are in front of. Which house stays the coolest?

### What you'll discover!

Plants can act as a shades to block sunlight and help us keep our homes cooler. In the summer time a tree with leaves will shade the home, decreasing the amount of sunlight striking the house, keeping it cooler. In the winter, when a tree drops it's leaves, the sunlight is allowed to hit the home to assist in keeping it warm.

The color your home (and especially the roof) is painted can have an impact on heating and cooling it. Light colors will reflect the sunlight. Dark colors will absorb more sunlight. So, if you paint a house light colors or have a light-colored roof, the house will stay cooler in the summer.