1. Energy

2. Conservation of Energy You cannot creat energy or destroy it. But you can transform it into another form. Eg energy from burning coal – ends up as kinetic energy or heat energy in a machine (steam train).

3. Conservation of Energy Energy can be converted/transformed from one form to another, but it cannot be created or destroyed.

4. Force Meters Newton Spring Balance A spring stretches when a pulling force acts on it A spring gets squashed or compressed when a forces pushes on it. A spring can be used to measure the strength of forces What unit do we measure force in?

5. Measuring Force The unit used to measure force is the newton (N) What is the force to lift an apple? – 1N Force to lift a 1kg bag of sugar – 10N Force you exert by sitting on someone – 400N Force needed to launch a rocket – 33000 000N

6. Comparing weight and mass Collect a series of objects that you can weigh with scales and then measure with the spring force. Write a data table showing the weight in g or kg and then N using the spring force. Remember the spring force measures the strength of force. Write a conclusion about what you notice. When finished, use your spring force to measure friction by pulling at item across the carpet, then the desk. Did you use more force on a different surface? Exercises page 236 and 237