Gravity

A simple and economical way to demonstrate the geometrical centre of gravity of two-dimensional objects, this apparatus comprises clear Perspex rod mounted on base, with a suspension screw at the top and four clear acrylic shapes circular, triangular, square and trapezoid. Each shape has suspension holes at various points around the edges. The point of intersection of lines drawn vertically down from the suspension point of or more holes gives the centre of gravity for each shape. For non-permanent markings, lines can be drawn using dry-wipe pens or similar.

This durable Projectile Launcher, of aluminium construction with hardened steel latches, has a string release trigger mechanism with 2 bore sights and pivots from horizontal to 90°. It comes with a 19 mm diameter ball which is easy to place in the launch position. Trajectories vary less than 1 cm because the ball does not spin when launched. The apparatus includes an assembled spring loaded gun, two balls of aluminium, an integral protractor and plumb line and comes complete with operating instructions. Weight: 1.74 kg. Dimensions (L x W x H): 400 x 100 x 180 mm.

This premium apparatus, from Frederiksen, allows accurate and reproducable free fall experiments to be carried out. The release mechanism at the top sends a start pulse to the timer when the ball is released, and a stop pulse is generated when the ball hits the contact plate at the bottom. • Connections via standard 4 mm safety connectors • No external power supply required so no risk of overheated coils • Four gold-plated steel balls and a ping-pong ball with metal thumb tacks included • Includes mirror to minimize parallax errors Requires separate timer (FO140110), stand and cables (not included).

This high quality timer, from Frederiksen, is particularly suitable for experiments such as 'g' by free fall and speed of sound, as well as other experiments where accurate timing is required. Inputs are via DIN 6 pole connectors (for Frederiksen photocells and microphones) or 4 mm safety sockets (for free fall experiments or other equipment). Compatible with the following equipment: • SO150400 microphone • TI170200 photogate • TI170100 speedgate • FO140105 freefall apparatus • Range: 0.03 ms to 27 hours • Resolution: 0.01 ms • digit LED display with floating decimal point • Manually controlled stopwatch option • Accepts start and stop signals from microphones, photocells or any on/off switch connected to the mm sockets • Power: 6 x AA batteries or mains adapter (included)

This simple but effective apparatus demonstrates that two projectiles launched at the same time, but with different trajectories, will hit the ground at the same time due to the force of gravity. In this case, one steel sphere is launched horizontally from spring-loaded L-shaped arm at the same time as an identical steel sphere is allowed to fall freely from the same height, but vertically. Both spheres will hit the ground at the same time. Launching mechanism is mounted on wooden block, which can be clamped to bench top, and comes complete with 2 steel spheres. The wooden block also incorporates an integral storage pocket for the spheres. Dimensions: 180 x 60 x 30 mm.

This fun and useful apparatus helps to demonstrate the 'Monkey and Hunter' experiment, to show how gravity affects projectile motion. The apparatus consists of a projectile 'gun' which fires a ping pong ball ('bullet') and model animal ('monkey') on an electromagnet release mechanism. The monkey is released at exactly the same time as the ball is fired, so should the gun be aimed directly at the monkey or just below it to allow for the distance it falls? Theory and practice will show that the gun should be aimed directly at the monkey, as both ball and monkey will fall at the same rate due to gravitational force.

Spare monkey for FO71860.

Spare solenoid and PCB for FO71860.

A solid metal sphere with small hook.

A solid metal sphere with small hook.

A solid metal sphere with small hook.

A solid metal sphere with small hook.

A solid metal sphere with small hook.

Apparatus to show the equality of acceleration under gravity between light and heavy objects in the absence of air resistance. Comprises a 100 cm acrylic tube with bungs at either end. A valve with a stopcock at one end allows a vacuum pump to be attached, and the air evacuated from the tube. Inside the tube is a coin, and a piece of paper (various laws prevent supply of a feather for this apparatus). When air is in the tube, the coin falls quickly but the paper is subject to air resistance and falls more slowly. With the air evacuated, the only force acting is gravity, so the two fall at equal rate, despite the difference in weight. The famous experiment on the Moon with hammer and feather can be seen here: http://timstar.co/HammerFeather

Use in conjunction with an accurate millisecond timer to calculate acceleration due to gravity. The timer starts when the ball bearing is released from the release unit, the base has an integral vibration sensor which stops the clock as the ball bearing hits the impact plate. Replace the ball bearing, reset the timer and the unit is ready to go again. When used with Lascells timers or other models with de-bounced inputs no additional power is required. If the timer used is found to have “bouncy” inputs then a 4 second delay can be added to the impact plate outputs by powering the unit with 9 V DC. Supplied with: Full instructions Base, release unit, 12 mm ball bearing, 8 mm ball bearing Features: Easy setup with integral vibration sensor No power required for millisecond timers with de-bounced inputs Two ball bearings allowing comparison of different masses Over-moulded rubber landing plate. Integrated de-bounce circuitry to add 4 second delay to outputs. (9 V DC required)

The Lascells Millisecond Timer is a fully functional, easy to use millisecond timer and has a clear, 4 digit LED display. Three sockets provide START and STOP inputs which respond to any change of switch settings i.e. normally closed to open or vice versa making triggering very simple and reliable. A single switch changes the timer from GATE 1 start and stop to GATE 1 start GATE 2 stop. In addition 3.5 mm sockets are provided to allow Lascells timer light gates to be connected. The timer has millisecond resolution for times up to 10 seconds and then the display auto-ranges for longer periods up to 9999s with corresponding reduced resolution. Supplied with mains plug-top adaptor and full instructions.