Is it possible for a human being to walk on water? If we look to the animal kingdom we find that it is a feat that some insects and one particular reptile have already mastered.

Insects like pond skaters and water-measurers don’t just float, they glide around on the surface of the water without ever breaking through it, using a property of water called surface tension. Surface tension produces a sort of ‘skin’ on the water; this skin is formed by the way molecules at the surface of the liquid are attracted to each other. A water molecule is made of an atom of oxygen attached to 2 atoms of hydrogen. The oxygen is a little bit negative and the hydrogen a little bit positive, and because opposites attract, each water molecule is pulled towards its neighbour and they join to form a skin.

The Basilisk or Jesus Christ Lizard however can also walk, or rather ‘run,’ on water. It is too heavy to either float or be supported by surface tension. It has powerful legs which give it a terrific running speed, a very long tail for balance and slightly webbed feet to increase the surface area of the foot. It ‘runs’ on water by moving very fast, slapping its foot down hard on the water such that it creates an upward reaction. The lizard creates an air pocket as it slices down with its foot, and then it pulls its foot out again quickly before the water has time to fill the hole and the lizard starts to sink. In fact if Jesus Christ Lizards do slow down, they sink … but they’re good swimmers.

Now that you know how the Jesus Christ Lizard performs its miracle have a go a making your own ‘water running Jesus Christ Lizard.’

It’s not easy – but this is how to do it. This is a model for real experts to build. The design is based around a right-angled gear box or ‘T’ box. You could either make this yourself (using an aluminium angle, push-fit bearings and bevel gears) or buy one from a shop. Using a gear box with a 2:1 reduction on it gives more force to the feet – but making the feet spin at the same rate as the drive shaft worked too.

Stuff you need

Materials
• Right-angled gear box (or ‘T’ box).
• 40 mm long section of aluminium angle, 40 x 40 x 3 mm
• 150 mm long section of aluminium angle, 40 x 15 x 3 mm
• 2” x 1” planed timber 400 mm long
• Three solid ½” diameter aluminium rods (20 mm lengths)
• Two 150 mm lengths of 3 mm diameter solid steel rod
• Four M4 grub screws (can be made from M4 bolts)
• Two M6 grub screws (can be made from M6 bolts)
• 70 mm length of M8 studding (threaded bar); (or use a long M8 bolt)
• Four 1” No. 8 wood screws
• One 1” M6 bolt
• One M6 nut
• Two M8 nuts
• Four 12 mm M4 screws
• Plastic for feet (approx 70 mm diameter x 2 mm thick for each)
• Large elastic bands 15 mm wide x 200 mm long

Tools
• Drill
• 3.3 or 3.5 mm; 4.5 mm; 5 mm; 6.5 mm drill bits
• M6 tap
• M4 tap
• Pozidrive screwdriver
• Jigsaw
• Hacksaw
• File or grinder
• Ruler
• Hot glue gun or Araldite
• Pliers

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