Artikelnummer EXPERIMENT MANUAL EXPERIMENT Thames & Kosmos UK Ltd, Goudhurst, Kent, TN17 2QZ Kent, Goudhurst, Ltd, UK &Kosmos Thames  USA 02903, RI, Providence, St., Friendship 301 &Kosmos, Thames | Germany Stuttgart, 5-7, 70184 Pfizerstr. KG, &Co. Verlags-GmbH Franckh-Kosmos , United Kingdom | 01580 212000  212000 |01580 Kingdom , United  |1-800-587-2872 |www.thamesandkosmos.com  711 2191-0 (0) +49 |www.thamesandkosmos.co.uk |www.kosmos.de

GOOD TO KNOW! If you are missing any parts, please contact Thames & Kosmos › › › KIT CONTENTS customer service.

US: [email protected] UK: [email protected] What’s inside your experiment kit:

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Checklist: Find – Inspect – Check off

No. Description Qty. Item No. No. Description Qty. Item No. 1 Short anchor pin, blue 6 7344-W10-C2B 19 11-hole rod 1 7413-W10-P1D 2 Anchor pin, red 15 7061-W10-C1R 20 15-hole dual rod 1 7413-W10-H1D 3 Joint pin 4 1156-W10-A1R 21 Curved rod 12 7061-W10-V1G3 4 Shaft plug 4 7026-W10-H1R 22 Square frame 2 7026-W10-T2S2 5 Shaft pin 1 7026-W10-J3D 23 Large frame 1 7413-W10-J1S1 6 Two-to-one converter 4 7061-W10-G1D 24 Curved frame 2 7392-W10-I1D 7 Tube, 80 mm 1 7337-W16-A1D 25 Motor axle 1 7026-W10-L1W 8 Tube, 30 mm 5 7400-W10-G1D 26 Axle, 30-mm 2 7413-W10-N1D 9 Washer 6 R12#3620 27 Small pulley 4 7344-W10-N3G 10 Nose piece 1 7402-W10-C2D 28 Rubber band, small 1 R10-02 11 90-degree converter - X 2 7061-W10-J1D 29 Rubber band, large 3 R10-28 12 90-degree converter - Y 2 7061-W10-J2D 30 Large foam ball 3 K30#7366-2 13 3-hole wide rounded rod 2 7404-W10-C1G2 31 Anchor pin lever 1 7061-W10-B1Y 14 3-hole cross rod 4 7026-W10-X1D 32 13x3 Frame 2 7406-W10-A1D 15 5-hole rod 4 7413-W10-K2D 33 3-hole bolt rod 2 7406-W10-B1G 16 5-hole dual rod C 2 7026-W10-S3D 34 5-hole L rod 2 7406-W10-B2G 17 7-hole wide rounded rod 2 7404-W10-C2G2 35 bolt 3 7406-W85-A-US 18 7-hole flat rounded rod 2 7404-W10-C3G2 2 &

› › › TABLE OF CONTENTS

Safety Information ...... Inside front A Word to Parents ...... 1 Kit Contents ...... 2 Table of Contents ...... 3

Preparation ...... 5 Set up a target and learn about accuracy and precision. Classic crossbow ...... 6 Elasticity, potential energy, and kinetic energy one ...... 9 Vectors, speed, and velocity Scorpion ...... 12 Gravity, acceleration, and air resistance Weighted ...... 15 Mass, weight, and gravitational potential energy Reverse-draw crossbow ...... 17 Hooke’s law Compound crossbow ...... 20 Pulleys Trebuchet two ...... 23 Levers and mechanical advantage ...... 25 motion y 10 Catapult one ...... 28 8 6 Kinetic energy, mass, and velocity 4 2 ...... 30 x Vertical distance (meters) distance Vertical 0 16 18 20 8 10 12 14 Maximizing time in air 0 2 4 6 Horizontal distance (meters)

3 Catapults & Crossbows

PREPARATION

Setting up a target YOU WILL NEED

› metal pie pan or other durable dish › tape › measuring stick or tape measure Low accuracy and low precision

HERE’S HOW

1 Place a metal pie pan upside down on the floor. This is your bull’s eye target.

2 Place a piece of tape 10 to 15 feet away from the pie pan. This is where you will stand when testing out your catapults and crossbows. Low accuracy and high precision

WHAT’S HAPPENING When you do the experiments with your crossbow, you should think about the accuracy and precision of where your bolts and land. Accuracy is how close your results (or shots) are to your target value — in this case, the center of the target. Precision is how often you are able to get the same value, or have your High accuracy and low precision projectile land in the same place. Look at the pictures to the right to see how accuracy and precision are related. Accuracy and precision are both critical concepts in the scientific world. As you perform the experiments for each model, think about how the changes affect your precision and accuracy. Keep a record of your results for the different experiments.

High accuracy and high precision

5 EXPERIMENT 6

Background Compound crossbow With the development of modern materials and manufacturing process, one of the most YOU WILL NEED common changes in modern crossbows is the 1 2 3 4 6 8 10 11 13 14 15 16 use of pulley systems. These crossbows are known as compound crossbows. The pulley 4 x 10 x 4 x 2 x 4 x 4 x 1 x 2 x 2 x 4 x 1 x 2 x system allows for the use of stiffer limbs which

17 18 23 24 transfer more energy into the bolt instead of the movement of the limbs.

1 x 2 x 1 x 2 x

26 27 28 29 31 2 1 x 2 x 2 x 1 x 1 x

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2 x 2 x 2 x 3 x

1

3

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Side view

20 EXPERIMENT 6

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Small rubber band

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WHAT’S HAPPENING Large rubber band A pulley is a wheel on an axle which supports the movement of a cable or rope. The type of pulley used in 15 Test out the crossbow by this crossbow is called a fixed pulley. The fixed pulley is firing some bolts. Notice a two-armed lever that rotates around a fulcrum as it does work. Its load arm and lever arm are equally long that when you load the in this case, so the user does not gain a mechanical bolt, the rubber band advantage. However, this slides around the pulley. pulley is useful because it Application of 16 changes the direction that Application of Now try removing the pulleys and wrapping the force is applied. load the rubber band around Looking at the rubber band Lever arm Load arm you can see that the the peg. Do you notice pulley allows the rubber any difference in band to be stretched Fulcrum behavior? farther, meaning that there is more energy in the rubber band. 22