Which common building materials block radio waves the most? You drive a remote-control car across a gymnasium floor while the transmitter sits behind different barriers. You test wood and glass and brick one at a time. For each material, you time how long the car takes to cross a set distance. A slower time means more signal interference. Wood caused the most interference. Glass came second. Brick caused the least.
Hypothesis
The hypothesis is that the cement (brick) will give the least interference and that the glass will have the most interference.
Radio waves carry data through the air from a transmitter to a receiver. A 27 MHz remote control sends signals across a gymnasium to drive a car on the far side. The transmitter sits outside the gymnasium door, and the car responds on the court. This shows that radio waves travel through open air to carry commands between devices.
Signal interference happens when a barrier blocks or weakens a signal traveling between two devices. In this experiment, a transmitter sits behind different barriers while a car drives across a gymnasium floor. Wood caused the most interference, and brick caused the least. Each common building material blocks radio waves by a different amount.
Method & Materials
You will place a remote control car's receiver back wheels on the edge of a basketball court, have someone hold the remote control transmitter outside the door of the gymnasium, and then place different materials between the transmitter and receiver to see which one causes the most interference.
You will need a stopwatch, a 27 MHz remote control car, 24 AA alkaline batteries, 6 9v batteries, cement (brick), wood, and glass.
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The results of the experiment were surprising. The wood offered the most interference, and then the glass and the brick offered the least interference to the radio waves. This was different than the hypothesis, which was that the cement (brick) would give the least interference and that the glass would have the most interference.
Why do this project?
This science project is interesting because it helps us understand which materials can cause interference to remote control devices.
Also Consider
Experiment variations to consider include testing different materials, such as metal or plastic, and testing different frequencies of radio waves.
Full project details
Additional information and source material for this project are available below.
