<?xml version="1.0" encoding='utf-8'?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1" title="Vacuum - Page 3 - Wikipedia">
<p>
<a accesskey="1" href="page.php?w=vacuum&amp;p=2">1.Previous</a><br />
<a accesskey="3" href="page.php?w=vacuum&amp;p=4">3.Next</a>
</p>
<p>partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas <a href="page.php?w=pressure">pressure</a> means higher-quality vacuum. For example, a typical <a href="page.php?w=vacuum_cleaner">vacuum cleaner</a> produces enough <a href="page.php?w=suction">suction</a> to reduce air pressure by around 20%. But higher-quality vacuums are possible. <a href="page.php?w=Ultra-high_vacuum">Ultra-high vacuum</a> chambers, common in chemistry, physics, and engineering, operate below one trillionth (10<sup>-12</sup>)</p><p>
<a accesskey="1" href="page.php?w=vacuum&amp;p=2">1.Previous</a><br />
<a accesskey="3" href="page.php?w=vacuum&amp;p=4">3.Next</a>
</p>

<do type="prev" label="Search">
        <go href="search.wml"/>
</do>

</card>
</wml>
