piston

If the workings of his engine were carefully concealed, you could see the pistons pumping and sparks flying when Nadal took to court.

Many past attempts have featured metal rods inserted into lava, pushed by hand or by spring-loaded piston, or even fired into the lava like a spear, to estimate the viscosity of the flow.

"I paid £250 for a diagnostics test. It turned out a diesel piston had gone and if it wasn't fixed it would damage the car further," she said.

“The source is like a piston,” says Adam Szabo, an astrophysicist at NASA’s Goddard Space Flight Center and principal investigator for the magnetometer.

The piston cores were taken inside pockmarks and at background sites adjacent to but outside of the pockmarks for comparison.