Echoes and Skylights at the Indoor Skate Park

Fixing the Old Warehouse Skate Park

1The Dockside Skate Park opened inside an old brick warehouse with concrete walls, a roof full of skylights and black rubber mats around the ramps. Skaters love it, but they have two complaints. On sunny afternoons, light pouring through the clear skylights makes hot, bright patches on the mats. And the building is loud: every shout, clatter and board slap bounces around the room, so skaters struggle to hear each other or a coach giving tips.

2Park manager Gwen Halvorsen asked an eighth-grade science class to test materials before she spends money on repairs. Students Sione Tupou and Marisol Ekwueme borrowed a light meter and tested small samples of each material in a lamp's beam. They measured how much of the light bounced back off each sample, how much passed through it, and worked out how much the sample absorbed. The three parts always add up to 100%. Their results are in the light table.

3Next they tested sound. A small speaker played a steady tone at a middle pitch toward each surface, and a sound meter measured how much sound came back. Samples were mounted against the thick warehouse wall, so almost no sound passed through them. The sound that was not reflected was absorbed, turning into a tiny amount of thermal energy in the material. Their results are in the sound table in Part 2.

4In air at room temperature, sound travels about 340 m/s. The longest concrete wall in the park is 34 m from the main ramp, which is where skaters notice the strongest echoes.